1 /** @file inifcns_nstdsums.cpp
3 * Implementation of some special functions that have a representation as nested sums.
6 * classical polylogarithm Li(n,x)
7 * multiple polylogarithm Li(lst(m_1,...,m_k),lst(x_1,...,x_k))
8 * G(lst(a_1,...,a_k),y) or G(lst(a_1,...,a_k),lst(s_1,...,s_k),y)
9 * Nielsen's generalized polylogarithm S(n,p,x)
10 * harmonic polylogarithm H(m,x) or H(lst(m_1,...,m_k),x)
11 * multiple zeta value zeta(m) or zeta(lst(m_1,...,m_k))
12 * alternating Euler sum zeta(m,s) or zeta(lst(m_1,...,m_k),lst(s_1,...,s_k))
16 * - All formulae used can be looked up in the following publications:
17 * [Kol] Nielsen's Generalized Polylogarithms, K.S.Kolbig, SIAM J.Math.Anal. 17 (1986), pp. 1232-1258.
18 * [Cra] Fast Evaluation of Multiple Zeta Sums, R.E.Crandall, Math.Comp. 67 (1998), pp. 1163-1172.
19 * [ReV] Harmonic Polylogarithms, E.Remiddi, J.A.M.Vermaseren, Int.J.Mod.Phys. A15 (2000), pp. 725-754
20 * [BBB] Special Values of Multiple Polylogarithms, J.Borwein, D.Bradley, D.Broadhurst, P.Lisonek, Trans.Amer.Math.Soc. 353/3 (2001), pp. 907-941
21 * [VSW] Numerical evaluation of multiple polylogarithms, J.Vollinga, S.Weinzierl, hep-ph/0410259
23 * - The order of parameters and arguments of Li and zeta is defined according to the nested sums
24 * representation. The parameters for H are understood as in [ReV]. They can be in expanded --- only
25 * 0, 1 and -1 --- or in compactified --- a string with zeros in front of 1 or -1 is written as a single
26 * number --- notation.
28 * - All functions can be nummerically evaluated with arguments in the whole complex plane. The parameters
29 * for Li, zeta and S must be positive integers. If you want to have an alternating Euler sum, you have
30 * to give the signs of the parameters as a second argument s to zeta(m,s) containing 1 and -1.
32 * - The calculation of classical polylogarithms is speeded up by using Bernoulli numbers and
33 * look-up tables. S uses look-up tables as well. The zeta function applies the algorithms in
34 * [Cra] and [BBB] for speed up. Multiple polylogarithms use Hoelder convolution [BBB].
36 * - The functions have no means to do a series expansion into nested sums. To do this, you have to convert
37 * these functions into the appropriate objects from the nestedsums library, do the expansion and convert
40 * - Numerical testing of this implementation has been performed by doing a comparison of results
41 * between this software and the commercial M.......... 4.1. Multiple zeta values have been checked
42 * by means of evaluations into simple zeta values. Harmonic polylogarithms have been checked by
43 * comparison to S(n,p,x) for corresponding parameter combinations and by continuity checks
44 * around |x|=1 along with comparisons to corresponding zeta functions. Multiple polylogarithms were
45 * checked against H and zeta and by means of shuffle and quasi-shuffle relations.
50 * GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
52 * This program is free software; you can redistribute it and/or modify
53 * it under the terms of the GNU General Public License as published by
54 * the Free Software Foundation; either version 2 of the License, or
55 * (at your option) any later version.
57 * This program is distributed in the hope that it will be useful,
58 * but WITHOUT ANY WARRANTY; without even the implied warranty of
59 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
60 * GNU General Public License for more details.
62 * You should have received a copy of the GNU General Public License
63 * along with this program; if not, write to the Free Software
64 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
79 #include "operators.h"
82 #include "relational.h"
91 //////////////////////////////////////////////////////////////////////
93 // Classical polylogarithm Li(n,x)
97 //////////////////////////////////////////////////////////////////////
100 // anonymous namespace for helper functions
104 // lookup table for factors built from Bernoulli numbers
106 std::vector<std::vector<cln::cl_N> > Xn;
107 // initial size of Xn that should suffice for 32bit machines (must be even)
108 const int xninitsizestep = 26;
109 int xninitsize = xninitsizestep;
113 // This function calculates the X_n. The X_n are needed for speed up of classical polylogarithms.
114 // With these numbers the polylogs can be calculated as follows:
115 // Li_p (x) = \sum_{n=0}^\infty X_{p-2}(n) u^{n+1}/(n+1)! with u = -log(1-x)
116 // X_0(n) = B_n (Bernoulli numbers)
117 // X_p(n) = \sum_{k=0}^n binomial(n,k) B_{n-k} / (k+1) * X_{p-1}(k)
118 // The calculation of Xn depends on X0 and X{n-1}.
119 // X_0 is special, it holds only the non-zero Bernoulli numbers with index 2 or greater.
120 // This results in a slightly more complicated algorithm for the X_n.
121 // The first index in Xn corresponds to the index of the polylog minus 2.
122 // The second index in Xn corresponds to the index from the actual sum.
126 // calculate X_2 and higher (corresponding to Li_4 and higher)
127 std::vector<cln::cl_N> buf(xninitsize);
128 std::vector<cln::cl_N>::iterator it = buf.begin();
130 *it = -(cln::expt(cln::cl_I(2),n+1) - 1) / cln::expt(cln::cl_I(2),n+1); // i == 1
132 for (int i=2; i<=xninitsize; i++) {
134 result = 0; // k == 0
136 result = Xn[0][i/2-1]; // k == 0
138 for (int k=1; k<i-1; k++) {
139 if ( !(((i-k) & 1) && ((i-k) > 1)) ) {
140 result = result + cln::binomial(i,k) * Xn[0][(i-k)/2-1] * Xn[n-1][k-1] / (k+1);
143 result = result - cln::binomial(i,i-1) * Xn[n-1][i-2] / 2 / i; // k == i-1
144 result = result + Xn[n-1][i-1] / (i+1); // k == i
151 // special case to handle the X_0 correct
152 std::vector<cln::cl_N> buf(xninitsize);
153 std::vector<cln::cl_N>::iterator it = buf.begin();
155 *it = cln::cl_I(-3)/cln::cl_I(4); // i == 1
157 *it = cln::cl_I(17)/cln::cl_I(36); // i == 2
159 for (int i=3; i<=xninitsize; i++) {
161 result = -Xn[0][(i-3)/2]/2;
162 *it = (cln::binomial(i,1)/cln::cl_I(2) + cln::binomial(i,i-1)/cln::cl_I(i))*result;
165 result = Xn[0][i/2-1] + Xn[0][i/2-1]/(i+1);
166 for (int k=1; k<i/2; k++) {
167 result = result + cln::binomial(i,k*2) * Xn[0][k-1] * Xn[0][i/2-k-1] / (k*2+1);
176 std::vector<cln::cl_N> buf(xninitsize/2);
177 std::vector<cln::cl_N>::iterator it = buf.begin();
178 for (int i=1; i<=xninitsize/2; i++) {
179 *it = bernoulli(i*2).to_cl_N();
188 // doubles the number of entries in each Xn[]
191 const int pos0 = xninitsize / 2;
193 for (int i=1; i<=xninitsizestep/2; ++i) {
194 Xn[0].push_back(bernoulli((i+pos0)*2).to_cl_N());
197 int xend = xninitsize + xninitsizestep;
200 for (int i=xninitsize+1; i<=xend; ++i) {
202 result = -Xn[0][(i-3)/2]/2;
203 Xn[1].push_back((cln::binomial(i,1)/cln::cl_I(2) + cln::binomial(i,i-1)/cln::cl_I(i))*result);
205 result = Xn[0][i/2-1] + Xn[0][i/2-1]/(i+1);
206 for (int k=1; k<i/2; k++) {
207 result = result + cln::binomial(i,k*2) * Xn[0][k-1] * Xn[0][i/2-k-1] / (k*2+1);
209 Xn[1].push_back(result);
213 for (int n=2; n<Xn.size(); ++n) {
214 for (int i=xninitsize+1; i<=xend; ++i) {
216 result = 0; // k == 0
218 result = Xn[0][i/2-1]; // k == 0
220 for (int k=1; k<i-1; ++k) {
221 if ( !(((i-k) & 1) && ((i-k) > 1)) ) {
222 result = result + cln::binomial(i,k) * Xn[0][(i-k)/2-1] * Xn[n-1][k-1] / (k+1);
225 result = result - cln::binomial(i,i-1) * Xn[n-1][i-2] / 2 / i; // k == i-1
226 result = result + Xn[n-1][i-1] / (i+1); // k == i
227 Xn[n].push_back(result);
231 xninitsize += xninitsizestep;
235 // calculates Li(2,x) without Xn
236 cln::cl_N Li2_do_sum(const cln::cl_N& x)
240 cln::cl_N num = x * cln::cl_float(1, cln::float_format(Digits));
241 cln::cl_I den = 1; // n^2 = 1
246 den = den + i; // n^2 = 4, 9, 16, ...
248 res = res + num / den;
249 } while (res != resbuf);
254 // calculates Li(2,x) with Xn
255 cln::cl_N Li2_do_sum_Xn(const cln::cl_N& x)
257 std::vector<cln::cl_N>::const_iterator it = Xn[0].begin();
258 std::vector<cln::cl_N>::const_iterator xend = Xn[0].end();
259 cln::cl_N u = -cln::log(1-x);
260 cln::cl_N factor = u * cln::cl_float(1, cln::float_format(Digits));
261 cln::cl_N uu = cln::square(u);
262 cln::cl_N res = u - uu/4;
267 factor = factor * uu / (2*i * (2*i+1));
268 res = res + (*it) * factor;
272 it = Xn[0].begin() + (i-1);
275 } while (res != resbuf);
280 // calculates Li(n,x), n>2 without Xn
281 cln::cl_N Lin_do_sum(int n, const cln::cl_N& x)
283 cln::cl_N factor = x * cln::cl_float(1, cln::float_format(Digits));
290 res = res + factor / cln::expt(cln::cl_I(i),n);
292 } while (res != resbuf);
297 // calculates Li(n,x), n>2 with Xn
298 cln::cl_N Lin_do_sum_Xn(int n, const cln::cl_N& x)
300 std::vector<cln::cl_N>::const_iterator it = Xn[n-2].begin();
301 std::vector<cln::cl_N>::const_iterator xend = Xn[n-2].end();
302 cln::cl_N u = -cln::log(1-x);
303 cln::cl_N factor = u * cln::cl_float(1, cln::float_format(Digits));
309 factor = factor * u / i;
310 res = res + (*it) * factor;
314 it = Xn[n-2].begin() + (i-2);
315 xend = Xn[n-2].end();
317 } while (res != resbuf);
322 // forward declaration needed by function Li_projection and C below
323 const cln::cl_N S_num(int n, int p, const cln::cl_N& x);
326 // helper function for classical polylog Li
327 cln::cl_N Li_projection(int n, const cln::cl_N& x, const cln::float_format_t& prec)
329 // treat n=2 as special case
331 // check if precalculated X0 exists
336 if (cln::realpart(x) < 0.5) {
337 // choose the faster algorithm
338 // the switching point was empirically determined. the optimal point
339 // depends on hardware, Digits, ... so an approx value is okay.
340 // it solves also the problem with precision due to the u=-log(1-x) transformation
341 if (cln::abs(cln::realpart(x)) < 0.25) {
343 return Li2_do_sum(x);
345 return Li2_do_sum_Xn(x);
348 // choose the faster algorithm
349 if (cln::abs(cln::realpart(x)) > 0.75) {
350 return -Li2_do_sum(1-x) - cln::log(x) * cln::log(1-x) + cln::zeta(2);
352 return -Li2_do_sum_Xn(1-x) - cln::log(x) * cln::log(1-x) + cln::zeta(2);
356 // check if precalculated Xn exist
358 for (int i=xnsize; i<n-1; i++) {
363 if (cln::realpart(x) < 0.5) {
364 // choose the faster algorithm
365 // with n>=12 the "normal" summation always wins against the method with Xn
366 if ((cln::abs(cln::realpart(x)) < 0.3) || (n >= 12)) {
367 return Lin_do_sum(n, x);
369 return Lin_do_sum_Xn(n, x);
372 cln::cl_N result = -cln::expt(cln::log(x), n-1) * cln::log(1-x) / cln::factorial(n-1);
373 for (int j=0; j<n-1; j++) {
374 result = result + (S_num(n-j-1, 1, 1) - S_num(1, n-j-1, 1-x))
375 * cln::expt(cln::log(x), j) / cln::factorial(j);
382 // helper function for classical polylog Li
383 const cln::cl_N Lin_numeric(const int n, const cln::cl_N& x)
387 return -cln::log(1-x);
398 return -(1-cln::expt(cln::cl_I(2),1-n)) * cln::zeta(n);
400 if (cln::abs(realpart(x)) < 0.4 && cln::abs(cln::abs(x)-1) < 0.01) {
401 cln::cl_N result = -cln::expt(cln::log(x), n-1) * cln::log(1-x) / cln::factorial(n-1);
402 for (int j=0; j<n-1; j++) {
403 result = result + (S_num(n-j-1, 1, 1) - S_num(1, n-j-1, 1-x))
404 * cln::expt(cln::log(x), j) / cln::factorial(j);
409 // what is the desired float format?
410 // first guess: default format
411 cln::float_format_t prec = cln::default_float_format;
412 const cln::cl_N value = x;
413 // second guess: the argument's format
414 if (!instanceof(realpart(x), cln::cl_RA_ring))
415 prec = cln::float_format(cln::the<cln::cl_F>(cln::realpart(value)));
416 else if (!instanceof(imagpart(x), cln::cl_RA_ring))
417 prec = cln::float_format(cln::the<cln::cl_F>(cln::imagpart(value)));
420 if (cln::abs(value) > 1) {
421 cln::cl_N result = -cln::expt(cln::log(-value),n) / cln::factorial(n);
422 // check if argument is complex. if it is real, the new polylog has to be conjugated.
423 if (cln::zerop(cln::imagpart(value))) {
425 result = result + conjugate(Li_projection(n, cln::recip(value), prec));
428 result = result - conjugate(Li_projection(n, cln::recip(value), prec));
433 result = result + Li_projection(n, cln::recip(value), prec);
436 result = result - Li_projection(n, cln::recip(value), prec);
440 for (int j=0; j<n-1; j++) {
441 add = add + (1+cln::expt(cln::cl_I(-1),n-j)) * (1-cln::expt(cln::cl_I(2),1-n+j))
442 * Lin_numeric(n-j,1) * cln::expt(cln::log(-value),j) / cln::factorial(j);
444 result = result - add;
448 return Li_projection(n, value, prec);
453 } // end of anonymous namespace
456 //////////////////////////////////////////////////////////////////////
458 // Multiple polylogarithm Li(n,x)
462 //////////////////////////////////////////////////////////////////////
465 // anonymous namespace for helper function
469 // performs the actual series summation for multiple polylogarithms
470 cln::cl_N multipleLi_do_sum(const std::vector<int>& s, const std::vector<cln::cl_N>& x)
472 // ensure all x <> 0.
473 for (std::vector<cln::cl_N>::const_iterator it = x.begin(); it != x.end(); ++it) {
474 if ( *it == 0 ) return cln::cl_float(0, cln::float_format(Digits));
477 const int j = s.size();
478 bool flag_accidental_zero = false;
480 std::vector<cln::cl_N> t(j);
481 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
488 t[j-1] = t[j-1] + cln::expt(x[j-1], q) / cln::expt(cln::cl_I(q),s[j-1]) * one;
489 for (int k=j-2; k>=0; k--) {
490 t[k] = t[k] + t[k+1] * cln::expt(x[k], q+j-1-k) / cln::expt(cln::cl_I(q+j-1-k), s[k]);
493 t[j-1] = t[j-1] + cln::expt(x[j-1], q) / cln::expt(cln::cl_I(q),s[j-1]) * one;
494 for (int k=j-2; k>=0; k--) {
495 flag_accidental_zero = cln::zerop(t[k+1]);
496 t[k] = t[k] + t[k+1] * cln::expt(x[k], q+j-1-k) / cln::expt(cln::cl_I(q+j-1-k), s[k]);
498 } while ( (t[0] != t0buf) || cln::zerop(t[0]) || flag_accidental_zero );
504 // converts parameter types and calls multipleLi_do_sum (convenience function for G_numeric)
505 cln::cl_N mLi_do_summation(const lst& m, const lst& x)
507 std::vector<int> m_int;
508 std::vector<cln::cl_N> x_cln;
509 for (lst::const_iterator itm = m.begin(), itx = x.begin(); itm != m.end(); ++itm, ++itx) {
510 m_int.push_back(ex_to<numeric>(*itm).to_int());
511 x_cln.push_back(ex_to<numeric>(*itx).to_cl_N());
513 return multipleLi_do_sum(m_int, x_cln);
517 // forward declaration for Li_eval()
518 lst convert_parameter_Li_to_H(const lst& m, const lst& x, ex& pf);
521 // type used by the transformation functions for G
522 typedef std::vector<int> Gparameter;
525 // G_eval1-function for G transformations
526 ex G_eval1(int a, int scale, const exvector& gsyms)
529 const ex& scs = gsyms[std::abs(scale)];
530 const ex& as = gsyms[std::abs(a)];
532 return -log(1 - scs/as);
537 return log(gsyms[std::abs(scale)]);
542 // G_eval-function for G transformations
543 ex G_eval(const Gparameter& a, int scale, const exvector& gsyms)
545 // check for properties of G
546 ex sc = gsyms[std::abs(scale)];
548 bool all_zero = true;
549 bool all_ones = true;
551 for (Gparameter::const_iterator it = a.begin(); it != a.end(); ++it) {
553 const ex sym = gsyms[std::abs(*it)];
567 // care about divergent G: shuffle to separate divergencies that will be canceled
568 // later on in the transformation
569 if (newa.nops() > 1 && newa.op(0) == sc && !all_ones && a.front()!=0) {
572 Gparameter::const_iterator it = a.begin();
574 for (; it != a.end(); ++it) {
575 short_a.push_back(*it);
577 ex result = G_eval1(a.front(), scale, gsyms) * G_eval(short_a, scale, gsyms);
578 it = short_a.begin();
579 for (int i=1; i<count_ones; ++i) {
582 for (; it != short_a.end(); ++it) {
585 Gparameter::const_iterator it2 = short_a.begin();
586 for (--it2; it2 != it;) {
588 newa.push_back(*it2);
590 newa.push_back(a[0]);
592 for (; it2 != short_a.end(); ++it2) {
593 newa.push_back(*it2);
595 result -= G_eval(newa, scale, gsyms);
597 return result / count_ones;
600 // G({1,...,1};y) -> G({1};y)^k / k!
601 if (all_ones && a.size() > 1) {
602 return pow(G_eval1(a.front(),scale, gsyms), count_ones) / factorial(count_ones);
605 // G({0,...,0};y) -> log(y)^k / k!
607 return pow(log(gsyms[std::abs(scale)]), a.size()) / factorial(a.size());
610 // no special cases anymore -> convert it into Li
613 ex argbuf = gsyms[std::abs(scale)];
615 for (Gparameter::const_iterator it=a.begin(); it!=a.end(); ++it) {
617 const ex& sym = gsyms[std::abs(*it)];
618 x.append(argbuf / sym);
626 return pow(-1, x.nops()) * Li(m, x);
630 // converts data for G: pending_integrals -> a
631 Gparameter convert_pending_integrals_G(const Gparameter& pending_integrals)
633 GINAC_ASSERT(pending_integrals.size() != 1);
635 if (pending_integrals.size() > 0) {
636 // get rid of the first element, which would stand for the new upper limit
637 Gparameter new_a(pending_integrals.begin()+1, pending_integrals.end());
640 // just return empty parameter list
647 // check the parameters a and scale for G and return information about convergence, depth, etc.
648 // convergent : true if G(a,scale) is convergent
649 // depth : depth of G(a,scale)
650 // trailing_zeros : number of trailing zeros of a
651 // min_it : iterator of a pointing on the smallest element in a
652 Gparameter::const_iterator check_parameter_G(const Gparameter& a, int scale,
653 bool& convergent, int& depth, int& trailing_zeros, Gparameter::const_iterator& min_it)
659 Gparameter::const_iterator lastnonzero = a.end();
660 for (Gparameter::const_iterator it = a.begin(); it != a.end(); ++it) {
661 if (std::abs(*it) > 0) {
665 if (std::abs(*it) < scale) {
667 if ((min_it == a.end()) || (std::abs(*it) < std::abs(*min_it))) {
675 return ++lastnonzero;
679 // add scale to pending_integrals if pending_integrals is empty
680 Gparameter prepare_pending_integrals(const Gparameter& pending_integrals, int scale)
682 GINAC_ASSERT(pending_integrals.size() != 1);
684 if (pending_integrals.size() > 0) {
685 return pending_integrals;
687 Gparameter new_pending_integrals;
688 new_pending_integrals.push_back(scale);
689 return new_pending_integrals;
694 // handles trailing zeroes for an otherwise convergent integral
695 ex trailing_zeros_G(const Gparameter& a, int scale, const exvector& gsyms)
698 int depth, trailing_zeros;
699 Gparameter::const_iterator last, dummyit;
700 last = check_parameter_G(a, scale, convergent, depth, trailing_zeros, dummyit);
702 GINAC_ASSERT(convergent);
704 if ((trailing_zeros > 0) && (depth > 0)) {
706 Gparameter new_a(a.begin(), a.end()-1);
707 result += G_eval1(0, scale, gsyms) * trailing_zeros_G(new_a, scale, gsyms);
708 for (Gparameter::const_iterator it = a.begin(); it != last; ++it) {
709 Gparameter new_a(a.begin(), it);
711 new_a.insert(new_a.end(), it, a.end()-1);
712 result -= trailing_zeros_G(new_a, scale, gsyms);
715 return result / trailing_zeros;
717 return G_eval(a, scale, gsyms);
722 // G transformation [VSW] (57),(58)
723 ex depth_one_trafo_G(const Gparameter& pending_integrals, const Gparameter& a, int scale, const exvector& gsyms)
725 // pendint = ( y1, b1, ..., br )
726 // a = ( 0, ..., 0, amin )
729 // int_0^y1 ds1/(s1-b1) ... int dsr/(sr-br) G(0, ..., 0, sr; y2)
730 // where sr replaces amin
732 GINAC_ASSERT(a.back() != 0);
733 GINAC_ASSERT(a.size() > 0);
736 Gparameter new_pending_integrals = prepare_pending_integrals(pending_integrals, std::abs(a.back()));
737 const int psize = pending_integrals.size();
740 // G(sr_{+-}; y2 ) = G(y2_{-+}; sr) - G(0; sr) + ln(-y2_{-+})
745 result += log(gsyms[ex_to<numeric>(scale).to_int()]);
747 new_pending_integrals.push_back(-scale);
750 new_pending_integrals.push_back(scale);
754 result *= trailing_zeros_G(convert_pending_integrals_G(pending_integrals),
755 pending_integrals.front(),
760 result += trailing_zeros_G(convert_pending_integrals_G(new_pending_integrals),
761 new_pending_integrals.front(),
765 new_pending_integrals.back() = 0;
766 result -= trailing_zeros_G(convert_pending_integrals_G(new_pending_integrals),
767 new_pending_integrals.front(),
774 // G_m(sr_{+-}; y2) = -zeta_m + int_0^y2 dt/t G_{m-1}( (1/y2)_{+-}; 1/t )
775 // - int_0^sr dt/t G_{m-1}( (1/y2)_{+-}; 1/t )
778 result -= zeta(a.size());
780 result *= trailing_zeros_G(convert_pending_integrals_G(pending_integrals),
781 pending_integrals.front(),
785 // term int_0^sr dt/t G_{m-1}( (1/y2)_{+-}; 1/t )
786 // = int_0^sr dt/t G_{m-1}( t_{+-}; y2 )
787 Gparameter new_a(a.begin()+1, a.end());
788 new_pending_integrals.push_back(0);
789 result -= depth_one_trafo_G(new_pending_integrals, new_a, scale, gsyms);
791 // term int_0^y2 dt/t G_{m-1}( (1/y2)_{+-}; 1/t )
792 // = int_0^y2 dt/t G_{m-1}( t_{+-}; y2 )
793 Gparameter new_pending_integrals_2;
794 new_pending_integrals_2.push_back(scale);
795 new_pending_integrals_2.push_back(0);
797 result += trailing_zeros_G(convert_pending_integrals_G(pending_integrals),
798 pending_integrals.front(),
800 * depth_one_trafo_G(new_pending_integrals_2, new_a, scale, gsyms);
802 result += depth_one_trafo_G(new_pending_integrals_2, new_a, scale, gsyms);
809 // forward declaration
810 ex shuffle_G(const Gparameter & a0, const Gparameter & a1, const Gparameter & a2,
811 const Gparameter& pendint, const Gparameter& a_old, int scale,
812 const exvector& gsyms);
815 // G transformation [VSW]
816 ex G_transform(const Gparameter& pendint, const Gparameter& a, int scale,
817 const exvector& gsyms)
819 // main recursion routine
821 // pendint = ( y1, b1, ..., br )
822 // a = ( a1, ..., amin, ..., aw )
825 // int_0^y1 ds1/(s1-b1) ... int dsr/(sr-br) G(a1,...,sr,...,aw,y2)
826 // where sr replaces amin
828 // find smallest alpha, determine depth and trailing zeros, and check for convergence
830 int depth, trailing_zeros;
831 Gparameter::const_iterator min_it;
832 Gparameter::const_iterator firstzero =
833 check_parameter_G(a, scale, convergent, depth, trailing_zeros, min_it);
834 int min_it_pos = min_it - a.begin();
836 // special case: all a's are zero
843 result = G_eval(a, scale, gsyms);
845 if (pendint.size() > 0) {
846 result *= trailing_zeros_G(convert_pending_integrals_G(pendint),
853 // handle trailing zeros
854 if (trailing_zeros > 0) {
856 Gparameter new_a(a.begin(), a.end()-1);
857 result += G_eval1(0, scale, gsyms) * G_transform(pendint, new_a, scale, gsyms);
858 for (Gparameter::const_iterator it = a.begin(); it != firstzero; ++it) {
859 Gparameter new_a(a.begin(), it);
861 new_a.insert(new_a.end(), it, a.end()-1);
862 result -= G_transform(pendint, new_a, scale, gsyms);
864 return result / trailing_zeros;
869 if (pendint.size() > 0) {
870 return G_eval(convert_pending_integrals_G(pendint),
871 pendint.front(), gsyms)*
872 G_eval(a, scale, gsyms);
874 return G_eval(a, scale, gsyms);
878 // call basic transformation for depth equal one
880 return depth_one_trafo_G(pendint, a, scale, gsyms);
884 // int_0^y1 ds1/(s1-b1) ... int dsr/(sr-br) G(a1,...,sr,...,aw,y2)
885 // = int_0^y1 ds1/(s1-b1) ... int dsr/(sr-br) G(a1,...,0,...,aw,y2)
886 // + int_0^y1 ds1/(s1-b1) ... int dsr/(sr-br) int_0^{sr} ds_{r+1} d/ds_{r+1} G(a1,...,s_{r+1},...,aw,y2)
888 // smallest element in last place
889 if (min_it + 1 == a.end()) {
890 do { --min_it; } while (*min_it == 0);
892 Gparameter a1(a.begin(),min_it+1);
893 Gparameter a2(min_it+1,a.end());
895 ex result = G_transform(pendint, a2, scale, gsyms)*
896 G_transform(empty, a1, scale, gsyms);
898 result -= shuffle_G(empty, a1, a2, pendint, a, scale, gsyms);
903 Gparameter::iterator changeit;
905 // first term G(a_1,..,0,...,a_w;a_0)
906 Gparameter new_pendint = prepare_pending_integrals(pendint, a[min_it_pos]);
907 Gparameter new_a = a;
908 new_a[min_it_pos] = 0;
909 ex result = G_transform(empty, new_a, scale, gsyms);
910 if (pendint.size() > 0) {
911 result *= trailing_zeros_G(convert_pending_integrals_G(pendint),
912 pendint.front(), gsyms);
916 changeit = new_a.begin() + min_it_pos;
917 changeit = new_a.erase(changeit);
918 if (changeit != new_a.begin()) {
919 // smallest in the middle
920 new_pendint.push_back(*changeit);
921 result -= trailing_zeros_G(convert_pending_integrals_G(new_pendint),
922 new_pendint.front(), gsyms)*
923 G_transform(empty, new_a, scale, gsyms);
924 int buffer = *changeit;
926 result += G_transform(new_pendint, new_a, scale, gsyms);
928 new_pendint.pop_back();
930 new_pendint.push_back(*changeit);
931 result += trailing_zeros_G(convert_pending_integrals_G(new_pendint),
932 new_pendint.front(), gsyms)*
933 G_transform(empty, new_a, scale, gsyms);
935 result -= G_transform(new_pendint, new_a, scale, gsyms);
937 // smallest at the front
938 new_pendint.push_back(scale);
939 result += trailing_zeros_G(convert_pending_integrals_G(new_pendint),
940 new_pendint.front(), gsyms)*
941 G_transform(empty, new_a, scale, gsyms);
942 new_pendint.back() = *changeit;
943 result -= trailing_zeros_G(convert_pending_integrals_G(new_pendint),
944 new_pendint.front(), gsyms)*
945 G_transform(empty, new_a, scale, gsyms);
947 result += G_transform(new_pendint, new_a, scale, gsyms);
953 // shuffles the two parameter list a1 and a2 and calls G_transform for every term except
954 // for the one that is equal to a_old
955 ex shuffle_G(const Gparameter & a0, const Gparameter & a1, const Gparameter & a2,
956 const Gparameter& pendint, const Gparameter& a_old, int scale,
957 const exvector& gsyms)
959 if (a1.size()==0 && a2.size()==0) {
960 // veto the one configuration we don't want
961 if ( a0 == a_old ) return 0;
963 return G_transform(pendint, a0, scale, gsyms);
969 aa0.insert(aa0.end(),a1.begin(),a1.end());
970 return shuffle_G(aa0, empty, empty, pendint, a_old, scale, gsyms);
976 aa0.insert(aa0.end(),a2.begin(),a2.end());
977 return shuffle_G(aa0, empty, empty, pendint, a_old, scale, gsyms);
980 Gparameter a1_removed(a1.begin()+1,a1.end());
981 Gparameter a2_removed(a2.begin()+1,a2.end());
986 a01.push_back( a1[0] );
987 a02.push_back( a2[0] );
989 return shuffle_G(a01, a1_removed, a2, pendint, a_old, scale, gsyms)
990 + shuffle_G(a02, a1, a2_removed, pendint, a_old, scale, gsyms);
993 // handles the transformations and the numerical evaluation of G
994 // the parameter x, s and y must only contain numerics
995 ex G_numeric(const lst& x, const lst& s, const ex& y);
997 // do acceleration transformation (hoelder convolution [BBB])
998 // the parameter x, s and y must only contain numerics
999 ex G_do_hoelder(const lst& x, const lst& s, const ex& y)
1002 const int size = x.nops();
1004 for (lst::const_iterator it = x.begin(); it != x.end(); ++it) {
1005 newx.append(*it / y);
1008 for (int r=0; r<=size; ++r) {
1009 ex buffer = pow(-1, r);
1014 for (lst::const_iterator it = newx.begin(); it != newx.end(); ++it) {
1025 for (int j=r; j>=1; --j) {
1026 qlstx.append(1-newx.op(j-1));
1027 if (newx.op(j-1).info(info_flags::real) && newx.op(j-1) > 1 && newx.op(j-1) <= 2) {
1028 qlsts.append( s.op(j-1));
1030 qlsts.append( -s.op(j-1));
1033 if (qlstx.nops() > 0) {
1034 buffer *= G_numeric(qlstx, qlsts, 1/q);
1038 for (int j=r+1; j<=size; ++j) {
1039 plstx.append(newx.op(j-1));
1040 plsts.append(s.op(j-1));
1042 if (plstx.nops() > 0) {
1043 buffer *= G_numeric(plstx, plsts, 1/p);
1050 // convergence transformation, used for numerical evaluation of G function.
1051 // the parameter x, s and y must only contain numerics
1052 static ex G_do_trafo(const lst& x, const lst& s, const ex& y)
1054 // sort (|x|<->position) to determine indices
1055 std::multimap<ex,int> sortmap;
1057 for (int i=0; i<x.nops(); ++i) {
1058 if (!x[i].is_zero()) {
1059 sortmap.insert(std::pair<ex,int>(abs(x[i]), i));
1063 // include upper limit (scale)
1064 sortmap.insert(std::pair<ex,int>(abs(y), x.nops()));
1066 // generate missing dummy-symbols
1068 // holding dummy-symbols for the G/Li transformations
1070 gsyms.push_back(symbol("GSYMS_ERROR"));
1072 for (std::multimap<ex,int>::const_iterator it = sortmap.begin(); it != sortmap.end(); ++it) {
1073 if (it != sortmap.begin()) {
1074 if (it->second < x.nops()) {
1075 if (x[it->second] == lastentry) {
1076 gsyms.push_back(gsyms.back());
1080 if (y == lastentry) {
1081 gsyms.push_back(gsyms.back());
1086 std::ostringstream os;
1088 gsyms.push_back(symbol(os.str()));
1090 if (it->second < x.nops()) {
1091 lastentry = x[it->second];
1097 // fill position data according to sorted indices and prepare substitution list
1098 Gparameter a(x.nops());
1102 for (std::multimap<ex,int>::const_iterator it = sortmap.begin(); it != sortmap.end(); ++it) {
1103 if (it->second < x.nops()) {
1104 if (s[it->second] > 0) {
1105 a[it->second] = pos;
1107 a[it->second] = -pos;
1109 subslst.append(gsyms[pos] == x[it->second]);
1112 subslst.append(gsyms[pos] == y);
1117 // do transformation
1119 ex result = G_transform(pendint, a, scale, gsyms);
1120 // replace dummy symbols with their values
1121 result = result.eval().expand();
1122 result = result.subs(subslst).evalf();
1127 // handles the transformations and the numerical evaluation of G
1128 // the parameter x, s and y must only contain numerics
1129 ex G_numeric(const lst& x, const lst& s, const ex& y)
1131 // check for convergence and necessary accelerations
1132 bool need_trafo = false;
1133 bool need_hoelder = false;
1135 for (lst::const_iterator it = x.begin(); it != x.end(); ++it) {
1136 if (!(*it).is_zero()) {
1138 if (abs(*it) - y < -pow(10,-Digits+1)) {
1141 if (abs((abs(*it) - y)/y) < 0.01) {
1142 need_hoelder = true;
1146 if (x.op(x.nops()-1).is_zero()) {
1149 if (depth == 1 && x.nops() == 2 && !need_trafo) {
1150 return -Li(x.nops(), y / x.op(x.nops()-1)).evalf();
1153 // do acceleration transformation (hoelder convolution [BBB])
1155 return G_do_hoelder(x, s, y);
1157 // convergence transformation
1159 return G_do_trafo(x, s, y);
1167 for (lst::const_iterator it = x.begin(); it != x.end(); ++it) {
1168 if ((*it).is_zero()) {
1171 newx.append(factor / (*it));
1179 return sign * numeric(mLi_do_summation(m, newx));
1183 ex mLi_numeric(const lst& m, const lst& x)
1185 // let G_numeric do the transformation
1189 for (lst::const_iterator itm = m.begin(), itx = x.begin(); itm != m.end(); ++itm, ++itx) {
1190 for (int i = 1; i < *itm; ++i) {
1194 newx.append(factor / *itx);
1198 return pow(-1, m.nops()) * G_numeric(newx, s, _ex1);
1202 } // end of anonymous namespace
1205 //////////////////////////////////////////////////////////////////////
1207 // Generalized multiple polylogarithm G(x, y) and G(x, s, y)
1211 //////////////////////////////////////////////////////////////////////
1214 static ex G2_evalf(const ex& x_, const ex& y)
1216 if (!y.info(info_flags::positive)) {
1217 return G(x_, y).hold();
1219 lst x = is_a<lst>(x_) ? ex_to<lst>(x_) : lst(x_);
1220 if (x.nops() == 0) {
1224 return G(x_, y).hold();
1227 bool all_zero = true;
1228 for (lst::const_iterator it = x.begin(); it != x.end(); ++it) {
1229 if (!(*it).info(info_flags::numeric)) {
1230 return G(x_, y).hold();
1235 if ( !ex_to<numeric>(*it).is_real() && ex_to<numeric>(*it).imag() < 0 ) {
1243 return pow(log(y), x.nops()) / factorial(x.nops());
1245 return G_numeric(x, s, y);
1249 static ex G2_eval(const ex& x_, const ex& y)
1251 //TODO eval to MZV or H or S or Lin
1253 if (!y.info(info_flags::positive)) {
1254 return G(x_, y).hold();
1256 lst x = is_a<lst>(x_) ? ex_to<lst>(x_) : lst(x_);
1257 if (x.nops() == 0) {
1261 return G(x_, y).hold();
1264 bool all_zero = true;
1265 bool crational = true;
1266 for (lst::const_iterator it = x.begin(); it != x.end(); ++it) {
1267 if (!(*it).info(info_flags::numeric)) {
1268 return G(x_, y).hold();
1270 if (!(*it).info(info_flags::crational)) {
1276 if ( !ex_to<numeric>(*it).is_real() && ex_to<numeric>(*it).imag() < 0 ) {
1284 return pow(log(y), x.nops()) / factorial(x.nops());
1286 if (!y.info(info_flags::crational)) {
1290 return G(x_, y).hold();
1292 return G_numeric(x, s, y);
1296 unsigned G2_SERIAL::serial = function::register_new(function_options("G", 2).
1297 evalf_func(G2_evalf).
1299 do_not_evalf_params().
1302 // derivative_func(G2_deriv).
1303 // print_func<print_latex>(G2_print_latex).
1306 static ex G3_evalf(const ex& x_, const ex& s_, const ex& y)
1308 if (!y.info(info_flags::positive)) {
1309 return G(x_, s_, y).hold();
1311 lst x = is_a<lst>(x_) ? ex_to<lst>(x_) : lst(x_);
1312 lst s = is_a<lst>(s_) ? ex_to<lst>(s_) : lst(s_);
1313 if (x.nops() != s.nops()) {
1314 return G(x_, s_, y).hold();
1316 if (x.nops() == 0) {
1320 return G(x_, s_, y).hold();
1323 bool all_zero = true;
1324 for (lst::const_iterator itx = x.begin(), its = s.begin(); itx != x.end(); ++itx, ++its) {
1325 if (!(*itx).info(info_flags::numeric)) {
1326 return G(x_, y).hold();
1328 if (!(*its).info(info_flags::real)) {
1329 return G(x_, y).hold();
1334 if ( ex_to<numeric>(*itx).is_real() ) {
1343 if ( ex_to<numeric>(*itx).imag() > 0 ) {
1352 return pow(log(y), x.nops()) / factorial(x.nops());
1354 return G_numeric(x, sn, y);
1358 static ex G3_eval(const ex& x_, const ex& s_, const ex& y)
1360 //TODO eval to MZV or H or S or Lin
1362 if (!y.info(info_flags::positive)) {
1363 return G(x_, s_, y).hold();
1365 lst x = is_a<lst>(x_) ? ex_to<lst>(x_) : lst(x_);
1366 lst s = is_a<lst>(s_) ? ex_to<lst>(s_) : lst(s_);
1367 if (x.nops() != s.nops()) {
1368 return G(x_, s_, y).hold();
1370 if (x.nops() == 0) {
1374 return G(x_, s_, y).hold();
1377 bool all_zero = true;
1378 bool crational = true;
1379 for (lst::const_iterator itx = x.begin(), its = s.begin(); itx != x.end(); ++itx, ++its) {
1380 if (!(*itx).info(info_flags::numeric)) {
1381 return G(x_, s_, y).hold();
1383 if (!(*its).info(info_flags::real)) {
1384 return G(x_, s_, y).hold();
1386 if (!(*itx).info(info_flags::crational)) {
1392 if ( ex_to<numeric>(*itx).is_real() ) {
1401 if ( ex_to<numeric>(*itx).imag() > 0 ) {
1410 return pow(log(y), x.nops()) / factorial(x.nops());
1412 if (!y.info(info_flags::crational)) {
1416 return G(x_, s_, y).hold();
1418 return G_numeric(x, sn, y);
1422 unsigned G3_SERIAL::serial = function::register_new(function_options("G", 3).
1423 evalf_func(G3_evalf).
1425 do_not_evalf_params().
1428 // derivative_func(G3_deriv).
1429 // print_func<print_latex>(G3_print_latex).
1432 //////////////////////////////////////////////////////////////////////
1434 // Classical polylogarithm and multiple polylogarithm Li(m,x)
1438 //////////////////////////////////////////////////////////////////////
1441 static ex Li_evalf(const ex& m_, const ex& x_)
1443 // classical polylogs
1444 if (m_.info(info_flags::posint)) {
1445 if (x_.info(info_flags::numeric)) {
1446 int m__ = ex_to<numeric>(m_).to_int();
1447 const cln::cl_N x__ = ex_to<numeric>(x_).to_cl_N();
1448 const cln::cl_N result = Lin_numeric(m__, x__);
1449 return numeric(result);
1451 // try to numerically evaluate second argument
1452 ex x_val = x_.evalf();
1453 if (x_val.info(info_flags::numeric)) {
1454 int m__ = ex_to<numeric>(m_).to_int();
1455 const cln::cl_N x__ = ex_to<numeric>(x_val).to_cl_N();
1456 const cln::cl_N result = Lin_numeric(m__, x__);
1457 return numeric(result);
1461 // multiple polylogs
1462 if (is_a<lst>(m_) && is_a<lst>(x_)) {
1464 const lst& m = ex_to<lst>(m_);
1465 const lst& x = ex_to<lst>(x_);
1466 if (m.nops() != x.nops()) {
1467 return Li(m_,x_).hold();
1469 if (x.nops() == 0) {
1472 if ((m.op(0) == _ex1) && (x.op(0) == _ex1)) {
1473 return Li(m_,x_).hold();
1476 for (lst::const_iterator itm = m.begin(), itx = x.begin(); itm != m.end(); ++itm, ++itx) {
1477 if (!(*itm).info(info_flags::posint)) {
1478 return Li(m_, x_).hold();
1480 if (!(*itx).info(info_flags::numeric)) {
1481 return Li(m_, x_).hold();
1488 return mLi_numeric(m, x);
1491 return Li(m_,x_).hold();
1495 static ex Li_eval(const ex& m_, const ex& x_)
1497 if (is_a<lst>(m_)) {
1498 if (is_a<lst>(x_)) {
1499 // multiple polylogs
1500 const lst& m = ex_to<lst>(m_);
1501 const lst& x = ex_to<lst>(x_);
1502 if (m.nops() != x.nops()) {
1503 return Li(m_,x_).hold();
1505 if (x.nops() == 0) {
1509 bool is_zeta = true;
1510 bool do_evalf = true;
1511 bool crational = true;
1512 for (lst::const_iterator itm = m.begin(), itx = x.begin(); itm != m.end(); ++itm, ++itx) {
1513 if (!(*itm).info(info_flags::posint)) {
1514 return Li(m_,x_).hold();
1516 if ((*itx != _ex1) && (*itx != _ex_1)) {
1517 if (itx != x.begin()) {
1525 if (!(*itx).info(info_flags::numeric)) {
1528 if (!(*itx).info(info_flags::crational)) {
1537 lst newm = convert_parameter_Li_to_H(m, x, prefactor);
1538 return prefactor * H(newm, x[0]);
1540 if (do_evalf && !crational) {
1541 return mLi_numeric(m,x);
1544 return Li(m_, x_).hold();
1545 } else if (is_a<lst>(x_)) {
1546 return Li(m_, x_).hold();
1549 // classical polylogs
1557 return (pow(2,1-m_)-1) * zeta(m_);
1563 if (x_.is_equal(I)) {
1564 return power(Pi,_ex2)/_ex_48 + Catalan*I;
1566 if (x_.is_equal(-I)) {
1567 return power(Pi,_ex2)/_ex_48 - Catalan*I;
1570 if (m_.info(info_flags::posint) && x_.info(info_flags::numeric) && !x_.info(info_flags::crational)) {
1571 int m__ = ex_to<numeric>(m_).to_int();
1572 const cln::cl_N x__ = ex_to<numeric>(x_).to_cl_N();
1573 const cln::cl_N result = Lin_numeric(m__, x__);
1574 return numeric(result);
1577 return Li(m_, x_).hold();
1581 static ex Li_series(const ex& m, const ex& x, const relational& rel, int order, unsigned options)
1583 if (is_a<lst>(m) || is_a<lst>(x)) {
1586 seq.push_back(expair(Li(m, x), 0));
1587 return pseries(rel, seq);
1590 // classical polylog
1591 const ex x_pt = x.subs(rel, subs_options::no_pattern);
1592 if (m.info(info_flags::numeric) && x_pt.info(info_flags::numeric)) {
1593 // First special case: x==0 (derivatives have poles)
1594 if (x_pt.is_zero()) {
1597 // manually construct the primitive expansion
1598 for (int i=1; i<order; ++i)
1599 ser += pow(s,i) / pow(numeric(i), m);
1600 // substitute the argument's series expansion
1601 ser = ser.subs(s==x.series(rel, order), subs_options::no_pattern);
1602 // maybe that was terminating, so add a proper order term
1604 nseq.push_back(expair(Order(_ex1), order));
1605 ser += pseries(rel, nseq);
1606 // reexpanding it will collapse the series again
1607 return ser.series(rel, order);
1609 // TODO special cases: x==1 (branch point) and x real, >=1 (branch cut)
1610 throw std::runtime_error("Li_series: don't know how to do the series expansion at this point!");
1612 // all other cases should be safe, by now:
1613 throw do_taylor(); // caught by function::series()
1617 static ex Li_deriv(const ex& m_, const ex& x_, unsigned deriv_param)
1619 GINAC_ASSERT(deriv_param < 2);
1620 if (deriv_param == 0) {
1623 if (m_.nops() > 1) {
1624 throw std::runtime_error("don't know how to derivate multiple polylogarithm!");
1627 if (is_a<lst>(m_)) {
1633 if (is_a<lst>(x_)) {
1639 return Li(m-1, x) / x;
1646 static void Li_print_latex(const ex& m_, const ex& x_, const print_context& c)
1649 if (is_a<lst>(m_)) {
1655 if (is_a<lst>(x_)) {
1660 c.s << "\\mbox{Li}_{";
1661 lst::const_iterator itm = m.begin();
1664 for (; itm != m.end(); itm++) {
1669 lst::const_iterator itx = x.begin();
1672 for (; itx != x.end(); itx++) {
1680 REGISTER_FUNCTION(Li,
1681 evalf_func(Li_evalf).
1683 series_func(Li_series).
1684 derivative_func(Li_deriv).
1685 print_func<print_latex>(Li_print_latex).
1686 do_not_evalf_params());
1689 //////////////////////////////////////////////////////////////////////
1691 // Nielsen's generalized polylogarithm S(n,p,x)
1695 //////////////////////////////////////////////////////////////////////
1698 // anonymous namespace for helper functions
1702 // lookup table for special Euler-Zagier-Sums (used for S_n,p(x))
1704 std::vector<std::vector<cln::cl_N> > Yn;
1705 int ynsize = 0; // number of Yn[]
1706 int ynlength = 100; // initial length of all Yn[i]
1709 // This function calculates the Y_n. The Y_n are needed for the evaluation of S_{n,p}(x).
1710 // The Y_n are basically Euler-Zagier sums with all m_i=1. They are subsums in the Z-sum
1711 // representing S_{n,p}(x).
1712 // The first index in Y_n corresponds to the parameter p minus one, i.e. the depth of the
1713 // equivalent Z-sum.
1714 // The second index in Y_n corresponds to the running index of the outermost sum in the full Z-sum
1715 // representing S_{n,p}(x).
1716 // The calculation of Y_n uses the values from Y_{n-1}.
1717 void fill_Yn(int n, const cln::float_format_t& prec)
1719 const int initsize = ynlength;
1720 //const int initsize = initsize_Yn;
1721 cln::cl_N one = cln::cl_float(1, prec);
1724 std::vector<cln::cl_N> buf(initsize);
1725 std::vector<cln::cl_N>::iterator it = buf.begin();
1726 std::vector<cln::cl_N>::iterator itprev = Yn[n-1].begin();
1727 *it = (*itprev) / cln::cl_N(n+1) * one;
1730 // sums with an index smaller than the depth are zero and need not to be calculated.
1731 // calculation starts with depth, which is n+2)
1732 for (int i=n+2; i<=initsize+n; i++) {
1733 *it = *(it-1) + (*itprev) / cln::cl_N(i) * one;
1739 std::vector<cln::cl_N> buf(initsize);
1740 std::vector<cln::cl_N>::iterator it = buf.begin();
1743 for (int i=2; i<=initsize; i++) {
1744 *it = *(it-1) + 1 / cln::cl_N(i) * one;
1753 // make Yn longer ...
1754 void make_Yn_longer(int newsize, const cln::float_format_t& prec)
1757 cln::cl_N one = cln::cl_float(1, prec);
1759 Yn[0].resize(newsize);
1760 std::vector<cln::cl_N>::iterator it = Yn[0].begin();
1762 for (int i=ynlength+1; i<=newsize; i++) {
1763 *it = *(it-1) + 1 / cln::cl_N(i) * one;
1767 for (int n=1; n<ynsize; n++) {
1768 Yn[n].resize(newsize);
1769 std::vector<cln::cl_N>::iterator it = Yn[n].begin();
1770 std::vector<cln::cl_N>::iterator itprev = Yn[n-1].begin();
1773 for (int i=ynlength+n+1; i<=newsize+n; i++) {
1774 *it = *(it-1) + (*itprev) / cln::cl_N(i) * one;
1784 // helper function for S(n,p,x)
1786 cln::cl_N C(int n, int p)
1790 for (int k=0; k<p; k++) {
1791 for (int j=0; j<=(n+k-1)/2; j++) {
1795 result = result - 2 * cln::expt(cln::pi(),2*j) * S_num(n-2*j,p,1) / cln::factorial(2*j);
1798 result = result + 2 * cln::expt(cln::pi(),2*j) * S_num(n-2*j,p,1) / cln::factorial(2*j);
1805 result = result + cln::factorial(n+k-1)
1806 * cln::expt(cln::pi(),2*j) * S_num(n+k-2*j,p-k,1)
1807 / (cln::factorial(k) * cln::factorial(n-1) * cln::factorial(2*j));
1810 result = result - cln::factorial(n+k-1)
1811 * cln::expt(cln::pi(),2*j) * S_num(n+k-2*j,p-k,1)
1812 / (cln::factorial(k) * cln::factorial(n-1) * cln::factorial(2*j));
1817 result = result - cln::factorial(n+k-1) * cln::expt(cln::pi(),2*j) * S_num(n+k-2*j,p-k,1)
1818 / (cln::factorial(k) * cln::factorial(n-1) * cln::factorial(2*j));
1821 result = result + cln::factorial(n+k-1)
1822 * cln::expt(cln::pi(),2*j) * S_num(n+k-2*j,p-k,1)
1823 / (cln::factorial(k) * cln::factorial(n-1) * cln::factorial(2*j));
1831 if (((np)/2+n) & 1) {
1832 result = -result - cln::expt(cln::pi(),np) / (np * cln::factorial(n-1) * cln::factorial(p));
1835 result = -result + cln::expt(cln::pi(),np) / (np * cln::factorial(n-1) * cln::factorial(p));
1843 // helper function for S(n,p,x)
1844 // [Kol] remark to (9.1)
1845 cln::cl_N a_k(int k)
1854 for (int m=2; m<=k; m++) {
1855 result = result + cln::expt(cln::cl_N(-1),m) * cln::zeta(m) * a_k(k-m);
1862 // helper function for S(n,p,x)
1863 // [Kol] remark to (9.1)
1864 cln::cl_N b_k(int k)
1873 for (int m=2; m<=k; m++) {
1874 result = result + cln::expt(cln::cl_N(-1),m) * cln::zeta(m) * b_k(k-m);
1881 // helper function for S(n,p,x)
1882 cln::cl_N S_do_sum(int n, int p, const cln::cl_N& x, const cln::float_format_t& prec)
1884 static cln::float_format_t oldprec = cln::default_float_format;
1887 return Li_projection(n+1, x, prec);
1890 // precision has changed, we need to clear lookup table Yn
1891 if ( oldprec != prec ) {
1898 // check if precalculated values are sufficient
1900 for (int i=ynsize; i<p-1; i++) {
1905 // should be done otherwise
1906 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
1907 cln::cl_N xf = x * one;
1908 //cln::cl_N xf = x * cln::cl_float(1, prec);
1912 cln::cl_N factor = cln::expt(xf, p);
1916 if (i-p >= ynlength) {
1918 make_Yn_longer(ynlength*2, prec);
1920 res = res + factor / cln::expt(cln::cl_I(i),n+1) * Yn[p-2][i-p]; // should we check it? or rely on magic number? ...
1921 //res = res + factor / cln::expt(cln::cl_I(i),n+1) * (*it); // should we check it? or rely on magic number? ...
1922 factor = factor * xf;
1924 } while (res != resbuf);
1930 // helper function for S(n,p,x)
1931 cln::cl_N S_projection(int n, int p, const cln::cl_N& x, const cln::float_format_t& prec)
1934 if (cln::abs(cln::realpart(x)) > cln::cl_F("0.5")) {
1936 cln::cl_N result = cln::expt(cln::cl_I(-1),p) * cln::expt(cln::log(x),n)
1937 * cln::expt(cln::log(1-x),p) / cln::factorial(n) / cln::factorial(p);
1939 for (int s=0; s<n; s++) {
1941 for (int r=0; r<p; r++) {
1942 res2 = res2 + cln::expt(cln::cl_I(-1),r) * cln::expt(cln::log(1-x),r)
1943 * S_do_sum(p-r,n-s,1-x,prec) / cln::factorial(r);
1945 result = result + cln::expt(cln::log(x),s) * (S_num(n-s,p,1) - res2) / cln::factorial(s);
1951 return S_do_sum(n, p, x, prec);
1955 // helper function for S(n,p,x)
1956 const cln::cl_N S_num(int n, int p, const cln::cl_N& x)
1960 // [Kol] (2.22) with (2.21)
1961 return cln::zeta(p+1);
1966 return cln::zeta(n+1);
1971 for (int nu=0; nu<n; nu++) {
1972 for (int rho=0; rho<=p; rho++) {
1973 result = result + b_k(n-nu-1) * b_k(p-rho) * a_k(nu+rho+1)
1974 * cln::factorial(nu+rho+1) / cln::factorial(rho) / cln::factorial(nu+1);
1977 result = result * cln::expt(cln::cl_I(-1),n+p-1);
1984 return -(1-cln::expt(cln::cl_I(2),-n)) * cln::zeta(n+1);
1986 // throw std::runtime_error("don't know how to evaluate this function!");
1989 // what is the desired float format?
1990 // first guess: default format
1991 cln::float_format_t prec = cln::default_float_format;
1992 const cln::cl_N value = x;
1993 // second guess: the argument's format
1994 if (!instanceof(realpart(value), cln::cl_RA_ring))
1995 prec = cln::float_format(cln::the<cln::cl_F>(cln::realpart(value)));
1996 else if (!instanceof(imagpart(value), cln::cl_RA_ring))
1997 prec = cln::float_format(cln::the<cln::cl_F>(cln::imagpart(value)));
2000 if ((cln::realpart(value) < -0.5) || (n == 0) || ((cln::abs(value) <= 1) && (cln::abs(value) > 0.95))) {
2002 cln::cl_N result = cln::expt(cln::cl_I(-1),p) * cln::expt(cln::log(value),n)
2003 * cln::expt(cln::log(1-value),p) / cln::factorial(n) / cln::factorial(p);
2005 for (int s=0; s<n; s++) {
2007 for (int r=0; r<p; r++) {
2008 res2 = res2 + cln::expt(cln::cl_I(-1),r) * cln::expt(cln::log(1-value),r)
2009 * S_num(p-r,n-s,1-value) / cln::factorial(r);
2011 result = result + cln::expt(cln::log(value),s) * (S_num(n-s,p,1) - res2) / cln::factorial(s);
2018 if (cln::abs(value) > 1) {
2022 for (int s=0; s<p; s++) {
2023 for (int r=0; r<=s; r++) {
2024 result = result + cln::expt(cln::cl_I(-1),s) * cln::expt(cln::log(-value),r) * cln::factorial(n+s-r-1)
2025 / cln::factorial(r) / cln::factorial(s-r) / cln::factorial(n-1)
2026 * S_num(n+s-r,p-s,cln::recip(value));
2029 result = result * cln::expt(cln::cl_I(-1),n);
2032 for (int r=0; r<n; r++) {
2033 res2 = res2 + cln::expt(cln::log(-value),r) * C(n-r,p) / cln::factorial(r);
2035 res2 = res2 + cln::expt(cln::log(-value),n+p) / cln::factorial(n+p);
2037 result = result + cln::expt(cln::cl_I(-1),p) * res2;
2042 return S_projection(n, p, value, prec);
2047 } // end of anonymous namespace
2050 //////////////////////////////////////////////////////////////////////
2052 // Nielsen's generalized polylogarithm S(n,p,x)
2056 //////////////////////////////////////////////////////////////////////
2059 static ex S_evalf(const ex& n, const ex& p, const ex& x)
2061 if (n.info(info_flags::posint) && p.info(info_flags::posint)) {
2062 const int n_ = ex_to<numeric>(n).to_int();
2063 const int p_ = ex_to<numeric>(p).to_int();
2064 if (is_a<numeric>(x)) {
2065 const cln::cl_N x_ = ex_to<numeric>(x).to_cl_N();
2066 const cln::cl_N result = S_num(n_, p_, x_);
2067 return numeric(result);
2069 ex x_val = x.evalf();
2070 if (is_a<numeric>(x_val)) {
2071 const cln::cl_N x_val_ = ex_to<numeric>(x_val).to_cl_N();
2072 const cln::cl_N result = S_num(n_, p_, x_val_);
2073 return numeric(result);
2077 return S(n, p, x).hold();
2081 static ex S_eval(const ex& n, const ex& p, const ex& x)
2083 if (n.info(info_flags::posint) && p.info(info_flags::posint)) {
2089 for (int i=ex_to<numeric>(p).to_int()-1; i>0; i--) {
2097 if (x.info(info_flags::numeric) && (!x.info(info_flags::crational))) {
2098 int n_ = ex_to<numeric>(n).to_int();
2099 int p_ = ex_to<numeric>(p).to_int();
2100 const cln::cl_N x_ = ex_to<numeric>(x).to_cl_N();
2101 const cln::cl_N result = S_num(n_, p_, x_);
2102 return numeric(result);
2107 return pow(-log(1-x), p) / factorial(p);
2109 return S(n, p, x).hold();
2113 static ex S_series(const ex& n, const ex& p, const ex& x, const relational& rel, int order, unsigned options)
2116 return Li(n+1, x).series(rel, order, options);
2119 const ex x_pt = x.subs(rel, subs_options::no_pattern);
2120 if (n.info(info_flags::posint) && p.info(info_flags::posint) && x_pt.info(info_flags::numeric)) {
2121 // First special case: x==0 (derivatives have poles)
2122 if (x_pt.is_zero()) {
2125 // manually construct the primitive expansion
2126 // subsum = Euler-Zagier-Sum is needed
2127 // dirty hack (slow ...) calculation of subsum:
2128 std::vector<ex> presubsum, subsum;
2129 subsum.push_back(0);
2130 for (int i=1; i<order-1; ++i) {
2131 subsum.push_back(subsum[i-1] + numeric(1, i));
2133 for (int depth=2; depth<p; ++depth) {
2135 for (int i=1; i<order-1; ++i) {
2136 subsum[i] = subsum[i-1] + numeric(1, i) * presubsum[i-1];
2140 for (int i=1; i<order; ++i) {
2141 ser += pow(s,i) / pow(numeric(i), n+1) * subsum[i-1];
2143 // substitute the argument's series expansion
2144 ser = ser.subs(s==x.series(rel, order), subs_options::no_pattern);
2145 // maybe that was terminating, so add a proper order term
2147 nseq.push_back(expair(Order(_ex1), order));
2148 ser += pseries(rel, nseq);
2149 // reexpanding it will collapse the series again
2150 return ser.series(rel, order);
2152 // TODO special cases: x==1 (branch point) and x real, >=1 (branch cut)
2153 throw std::runtime_error("S_series: don't know how to do the series expansion at this point!");
2155 // all other cases should be safe, by now:
2156 throw do_taylor(); // caught by function::series()
2160 static ex S_deriv(const ex& n, const ex& p, const ex& x, unsigned deriv_param)
2162 GINAC_ASSERT(deriv_param < 3);
2163 if (deriv_param < 2) {
2167 return S(n-1, p, x) / x;
2169 return S(n, p-1, x) / (1-x);
2174 static void S_print_latex(const ex& n, const ex& p, const ex& x, const print_context& c)
2176 c.s << "\\mbox{S}_{";
2186 REGISTER_FUNCTION(S,
2187 evalf_func(S_evalf).
2189 series_func(S_series).
2190 derivative_func(S_deriv).
2191 print_func<print_latex>(S_print_latex).
2192 do_not_evalf_params());
2195 //////////////////////////////////////////////////////////////////////
2197 // Harmonic polylogarithm H(m,x)
2201 //////////////////////////////////////////////////////////////////////
2204 // anonymous namespace for helper functions
2208 // regulates the pole (used by 1/x-transformation)
2209 symbol H_polesign("IMSIGN");
2212 // convert parameters from H to Li representation
2213 // parameters are expected to be in expanded form, i.e. only 0, 1 and -1
2214 // returns true if some parameters are negative
2215 bool convert_parameter_H_to_Li(const lst& l, lst& m, lst& s, ex& pf)
2217 // expand parameter list
2219 for (lst::const_iterator it = l.begin(); it != l.end(); it++) {
2221 for (ex count=*it-1; count > 0; count--) {
2225 } else if (*it < -1) {
2226 for (ex count=*it+1; count < 0; count++) {
2237 bool has_negative_parameters = false;
2239 for (lst::const_iterator it = mexp.begin(); it != mexp.end(); it++) {
2245 m.append((*it+acc-1) * signum);
2247 m.append((*it-acc+1) * signum);
2253 has_negative_parameters = true;
2256 if (has_negative_parameters) {
2257 for (int i=0; i<m.nops(); i++) {
2259 m.let_op(i) = -m.op(i);
2267 return has_negative_parameters;
2271 // recursivly transforms H to corresponding multiple polylogarithms
2272 struct map_trafo_H_convert_to_Li : public map_function
2274 ex operator()(const ex& e)
2276 if (is_a<add>(e) || is_a<mul>(e)) {
2277 return e.map(*this);
2279 if (is_a<function>(e)) {
2280 std::string name = ex_to<function>(e).get_name();
2283 if (is_a<lst>(e.op(0))) {
2284 parameter = ex_to<lst>(e.op(0));
2286 parameter = lst(e.op(0));
2293 if (convert_parameter_H_to_Li(parameter, m, s, pf)) {
2294 s.let_op(0) = s.op(0) * arg;
2295 return pf * Li(m, s).hold();
2297 for (int i=0; i<m.nops(); i++) {
2300 s.let_op(0) = s.op(0) * arg;
2301 return Li(m, s).hold();
2310 // recursivly transforms H to corresponding zetas
2311 struct map_trafo_H_convert_to_zeta : public map_function
2313 ex operator()(const ex& e)
2315 if (is_a<add>(e) || is_a<mul>(e)) {
2316 return e.map(*this);
2318 if (is_a<function>(e)) {
2319 std::string name = ex_to<function>(e).get_name();
2322 if (is_a<lst>(e.op(0))) {
2323 parameter = ex_to<lst>(e.op(0));
2325 parameter = lst(e.op(0));
2331 if (convert_parameter_H_to_Li(parameter, m, s, pf)) {
2332 return pf * zeta(m, s);
2343 // remove trailing zeros from H-parameters
2344 struct map_trafo_H_reduce_trailing_zeros : public map_function
2346 ex operator()(const ex& e)
2348 if (is_a<add>(e) || is_a<mul>(e)) {
2349 return e.map(*this);
2351 if (is_a<function>(e)) {
2352 std::string name = ex_to<function>(e).get_name();
2355 if (is_a<lst>(e.op(0))) {
2356 parameter = ex_to<lst>(e.op(0));
2358 parameter = lst(e.op(0));
2361 if (parameter.op(parameter.nops()-1) == 0) {
2364 if (parameter.nops() == 1) {
2369 lst::const_iterator it = parameter.begin();
2370 while ((it != parameter.end()) && (*it == 0)) {
2373 if (it == parameter.end()) {
2374 return pow(log(arg),parameter.nops()) / factorial(parameter.nops());
2378 parameter.remove_last();
2379 int lastentry = parameter.nops();
2380 while ((lastentry > 0) && (parameter[lastentry-1] == 0)) {
2385 ex result = log(arg) * H(parameter,arg).hold();
2387 for (ex i=0; i<lastentry; i++) {
2388 if (parameter[i] > 0) {
2390 result -= (acc + parameter[i]-1) * H(parameter, arg).hold();
2393 } else if (parameter[i] < 0) {
2395 result -= (acc + abs(parameter[i]+1)) * H(parameter, arg).hold();
2403 if (lastentry < parameter.nops()) {
2404 result = result / (parameter.nops()-lastentry+1);
2405 return result.map(*this);
2417 // returns an expression with zeta functions corresponding to the parameter list for H
2418 ex convert_H_to_zeta(const lst& m)
2420 symbol xtemp("xtemp");
2421 map_trafo_H_reduce_trailing_zeros filter;
2422 map_trafo_H_convert_to_zeta filter2;
2423 return filter2(filter(H(m, xtemp).hold())).subs(xtemp == 1);
2427 // convert signs form Li to H representation
2428 lst convert_parameter_Li_to_H(const lst& m, const lst& x, ex& pf)
2431 lst::const_iterator itm = m.begin();
2432 lst::const_iterator itx = ++x.begin();
2437 while (itx != x.end()) {
2438 signum *= (*itx > 0) ? 1 : -1;
2440 res.append((*itm) * signum);
2448 // multiplies an one-dimensional H with another H
2450 ex trafo_H_mult(const ex& h1, const ex& h2)
2455 ex h1nops = h1.op(0).nops();
2456 ex h2nops = h2.op(0).nops();
2458 hshort = h2.op(0).op(0);
2459 hlong = ex_to<lst>(h1.op(0));
2461 hshort = h1.op(0).op(0);
2463 hlong = ex_to<lst>(h2.op(0));
2465 hlong = h2.op(0).op(0);
2468 for (int i=0; i<=hlong.nops(); i++) {
2472 newparameter.append(hlong[j]);
2474 newparameter.append(hshort);
2475 for (; j<hlong.nops(); j++) {
2476 newparameter.append(hlong[j]);
2478 res += H(newparameter, h1.op(1)).hold();
2484 // applies trafo_H_mult recursively on expressions
2485 struct map_trafo_H_mult : public map_function
2487 ex operator()(const ex& e)
2490 return e.map(*this);
2498 for (int pos=0; pos<e.nops(); pos++) {
2499 if (is_a<power>(e.op(pos)) && is_a<function>(e.op(pos).op(0))) {
2500 std::string name = ex_to<function>(e.op(pos).op(0)).get_name();
2502 for (ex i=0; i<e.op(pos).op(1); i++) {
2503 Hlst.append(e.op(pos).op(0));
2507 } else if (is_a<function>(e.op(pos))) {
2508 std::string name = ex_to<function>(e.op(pos)).get_name();
2510 if (e.op(pos).op(0).nops() > 1) {
2513 Hlst.append(e.op(pos));
2518 result *= e.op(pos);
2521 if (Hlst.nops() > 0) {
2522 firstH = Hlst[Hlst.nops()-1];
2529 if (Hlst.nops() > 0) {
2530 ex buffer = trafo_H_mult(firstH, Hlst.op(0));
2532 for (int i=1; i<Hlst.nops(); i++) {
2533 result *= Hlst.op(i);
2535 result = result.expand();
2536 map_trafo_H_mult recursion;
2537 return recursion(result);
2548 // do integration [ReV] (55)
2549 // put parameter 0 in front of existing parameters
2550 ex trafo_H_1tx_prepend_zero(const ex& e, const ex& arg)
2554 if (is_a<function>(e)) {
2555 name = ex_to<function>(e).get_name();
2560 for (int i=0; i<e.nops(); i++) {
2561 if (is_a<function>(e.op(i))) {
2562 std::string name = ex_to<function>(e.op(i)).get_name();
2570 lst newparameter = ex_to<lst>(h.op(0));
2571 newparameter.prepend(0);
2572 ex addzeta = convert_H_to_zeta(newparameter);
2573 return e.subs(h == (addzeta-H(newparameter, h.op(1)).hold())).expand();
2575 return e * (-H(lst(0),1/arg).hold());
2580 // do integration [ReV] (49)
2581 // put parameter 1 in front of existing parameters
2582 ex trafo_H_prepend_one(const ex& e, const ex& arg)
2586 if (is_a<function>(e)) {
2587 name = ex_to<function>(e).get_name();
2592 for (int i=0; i<e.nops(); i++) {
2593 if (is_a<function>(e.op(i))) {
2594 std::string name = ex_to<function>(e.op(i)).get_name();
2602 lst newparameter = ex_to<lst>(h.op(0));
2603 newparameter.prepend(1);
2604 return e.subs(h == H(newparameter, h.op(1)).hold());
2606 return e * H(lst(1),1-arg).hold();
2611 // do integration [ReV] (55)
2612 // put parameter -1 in front of existing parameters
2613 ex trafo_H_1tx_prepend_minusone(const ex& e, const ex& arg)
2617 if (is_a<function>(e)) {
2618 name = ex_to<function>(e).get_name();
2623 for (int i=0; i<e.nops(); i++) {
2624 if (is_a<function>(e.op(i))) {
2625 std::string name = ex_to<function>(e.op(i)).get_name();
2633 lst newparameter = ex_to<lst>(h.op(0));
2634 newparameter.prepend(-1);
2635 ex addzeta = convert_H_to_zeta(newparameter);
2636 return e.subs(h == (addzeta-H(newparameter, h.op(1)).hold())).expand();
2638 ex addzeta = convert_H_to_zeta(lst(-1));
2639 return (e * (addzeta - H(lst(-1),1/arg).hold())).expand();
2644 // do integration [ReV] (55)
2645 // put parameter -1 in front of existing parameters
2646 ex trafo_H_1mxt1px_prepend_minusone(const ex& e, const ex& arg)
2650 if (is_a<function>(e)) {
2651 name = ex_to<function>(e).get_name();
2656 for (int i=0; i<e.nops(); i++) {
2657 if (is_a<function>(e.op(i))) {
2658 std::string name = ex_to<function>(e.op(i)).get_name();
2666 lst newparameter = ex_to<lst>(h.op(0));
2667 newparameter.prepend(-1);
2668 return e.subs(h == H(newparameter, h.op(1)).hold()).expand();
2670 return (e * H(lst(-1),(1-arg)/(1+arg)).hold()).expand();
2675 // do integration [ReV] (55)
2676 // put parameter 1 in front of existing parameters
2677 ex trafo_H_1mxt1px_prepend_one(const ex& e, const ex& arg)
2681 if (is_a<function>(e)) {
2682 name = ex_to<function>(e).get_name();
2687 for (int i=0; i<e.nops(); i++) {
2688 if (is_a<function>(e.op(i))) {
2689 std::string name = ex_to<function>(e.op(i)).get_name();
2697 lst newparameter = ex_to<lst>(h.op(0));
2698 newparameter.prepend(1);
2699 return e.subs(h == H(newparameter, h.op(1)).hold()).expand();
2701 return (e * H(lst(1),(1-arg)/(1+arg)).hold()).expand();
2706 // do x -> 1-x transformation
2707 struct map_trafo_H_1mx : public map_function
2709 ex operator()(const ex& e)
2711 if (is_a<add>(e) || is_a<mul>(e)) {
2712 return e.map(*this);
2715 if (is_a<function>(e)) {
2716 std::string name = ex_to<function>(e).get_name();
2719 lst parameter = ex_to<lst>(e.op(0));
2722 // special cases if all parameters are either 0, 1 or -1
2723 bool allthesame = true;
2724 if (parameter.op(0) == 0) {
2725 for (int i=1; i<parameter.nops(); i++) {
2726 if (parameter.op(i) != 0) {
2733 for (int i=parameter.nops(); i>0; i--) {
2734 newparameter.append(1);
2736 return pow(-1, parameter.nops()) * H(newparameter, 1-arg).hold();
2738 } else if (parameter.op(0) == -1) {
2739 throw std::runtime_error("map_trafo_H_1mx: cannot handle weights equal -1!");
2741 for (int i=1; i<parameter.nops(); i++) {
2742 if (parameter.op(i) != 1) {
2749 for (int i=parameter.nops(); i>0; i--) {
2750 newparameter.append(0);
2752 return pow(-1, parameter.nops()) * H(newparameter, 1-arg).hold();
2756 lst newparameter = parameter;
2757 newparameter.remove_first();
2759 if (parameter.op(0) == 0) {
2762 ex res = convert_H_to_zeta(parameter);
2763 //ex res = convert_from_RV(parameter, 1).subs(H(wild(1),wild(2))==zeta(wild(1)));
2764 map_trafo_H_1mx recursion;
2765 ex buffer = recursion(H(newparameter, arg).hold());
2766 if (is_a<add>(buffer)) {
2767 for (int i=0; i<buffer.nops(); i++) {
2768 res -= trafo_H_prepend_one(buffer.op(i), arg);
2771 res -= trafo_H_prepend_one(buffer, arg);
2778 map_trafo_H_1mx recursion;
2779 map_trafo_H_mult unify;
2780 ex res = H(lst(1), arg).hold() * H(newparameter, arg).hold();
2782 while (parameter.op(firstzero) == 1) {
2785 for (int i=firstzero-1; i<parameter.nops()-1; i++) {
2789 newparameter.append(parameter[j+1]);
2791 newparameter.append(1);
2792 for (; j<parameter.nops()-1; j++) {
2793 newparameter.append(parameter[j+1]);
2795 res -= H(newparameter, arg).hold();
2797 res = recursion(res).expand() / firstzero;
2807 // do x -> 1/x transformation
2808 struct map_trafo_H_1overx : public map_function
2810 ex operator()(const ex& e)
2812 if (is_a<add>(e) || is_a<mul>(e)) {
2813 return e.map(*this);
2816 if (is_a<function>(e)) {
2817 std::string name = ex_to<function>(e).get_name();
2820 lst parameter = ex_to<lst>(e.op(0));
2823 // special cases if all parameters are either 0, 1 or -1
2824 bool allthesame = true;
2825 if (parameter.op(0) == 0) {
2826 for (int i=1; i<parameter.nops(); i++) {
2827 if (parameter.op(i) != 0) {
2833 return pow(-1, parameter.nops()) * H(parameter, 1/arg).hold();
2835 } else if (parameter.op(0) == -1) {
2836 for (int i=1; i<parameter.nops(); i++) {
2837 if (parameter.op(i) != -1) {
2843 map_trafo_H_mult unify;
2844 return unify((pow(H(lst(-1),1/arg).hold() - H(lst(0),1/arg).hold(), parameter.nops())
2845 / factorial(parameter.nops())).expand());
2848 for (int i=1; i<parameter.nops(); i++) {
2849 if (parameter.op(i) != 1) {
2855 map_trafo_H_mult unify;
2856 return unify((pow(H(lst(1),1/arg).hold() + H(lst(0),1/arg).hold() + H_polesign, parameter.nops())
2857 / factorial(parameter.nops())).expand());
2861 lst newparameter = parameter;
2862 newparameter.remove_first();
2864 if (parameter.op(0) == 0) {
2867 ex res = convert_H_to_zeta(parameter);
2868 map_trafo_H_1overx recursion;
2869 ex buffer = recursion(H(newparameter, arg).hold());
2870 if (is_a<add>(buffer)) {
2871 for (int i=0; i<buffer.nops(); i++) {
2872 res += trafo_H_1tx_prepend_zero(buffer.op(i), arg);
2875 res += trafo_H_1tx_prepend_zero(buffer, arg);
2879 } else if (parameter.op(0) == -1) {
2881 // leading negative one
2882 ex res = convert_H_to_zeta(parameter);
2883 map_trafo_H_1overx recursion;
2884 ex buffer = recursion(H(newparameter, arg).hold());
2885 if (is_a<add>(buffer)) {
2886 for (int i=0; i<buffer.nops(); i++) {
2887 res += trafo_H_1tx_prepend_zero(buffer.op(i), arg) - trafo_H_1tx_prepend_minusone(buffer.op(i), arg);
2890 res += trafo_H_1tx_prepend_zero(buffer, arg) - trafo_H_1tx_prepend_minusone(buffer, arg);
2897 map_trafo_H_1overx recursion;
2898 map_trafo_H_mult unify;
2899 ex res = H(lst(1), arg).hold() * H(newparameter, arg).hold();
2901 while (parameter.op(firstzero) == 1) {
2904 for (int i=firstzero-1; i<parameter.nops()-1; i++) {
2908 newparameter.append(parameter[j+1]);
2910 newparameter.append(1);
2911 for (; j<parameter.nops()-1; j++) {
2912 newparameter.append(parameter[j+1]);
2914 res -= H(newparameter, arg).hold();
2916 res = recursion(res).expand() / firstzero;
2928 // do x -> (1-x)/(1+x) transformation
2929 struct map_trafo_H_1mxt1px : public map_function
2931 ex operator()(const ex& e)
2933 if (is_a<add>(e) || is_a<mul>(e)) {
2934 return e.map(*this);
2937 if (is_a<function>(e)) {
2938 std::string name = ex_to<function>(e).get_name();
2941 lst parameter = ex_to<lst>(e.op(0));
2944 // special cases if all parameters are either 0, 1 or -1
2945 bool allthesame = true;
2946 if (parameter.op(0) == 0) {
2947 for (int i=1; i<parameter.nops(); i++) {
2948 if (parameter.op(i) != 0) {
2954 map_trafo_H_mult unify;
2955 return unify((pow(-H(lst(1),(1-arg)/(1+arg)).hold() - H(lst(-1),(1-arg)/(1+arg)).hold(), parameter.nops())
2956 / factorial(parameter.nops())).expand());
2958 } else if (parameter.op(0) == -1) {
2959 for (int i=1; i<parameter.nops(); i++) {
2960 if (parameter.op(i) != -1) {
2966 map_trafo_H_mult unify;
2967 return unify((pow(log(2) - H(lst(-1),(1-arg)/(1+arg)).hold(), parameter.nops())
2968 / factorial(parameter.nops())).expand());
2971 for (int i=1; i<parameter.nops(); i++) {
2972 if (parameter.op(i) != 1) {
2978 map_trafo_H_mult unify;
2979 return unify((pow(-log(2) - H(lst(0),(1-arg)/(1+arg)).hold() + H(lst(-1),(1-arg)/(1+arg)).hold(), parameter.nops())
2980 / factorial(parameter.nops())).expand());
2984 lst newparameter = parameter;
2985 newparameter.remove_first();
2987 if (parameter.op(0) == 0) {
2990 ex res = convert_H_to_zeta(parameter);
2991 map_trafo_H_1mxt1px recursion;
2992 ex buffer = recursion(H(newparameter, arg).hold());
2993 if (is_a<add>(buffer)) {
2994 for (int i=0; i<buffer.nops(); i++) {
2995 res -= trafo_H_1mxt1px_prepend_one(buffer.op(i), arg) + trafo_H_1mxt1px_prepend_minusone(buffer.op(i), arg);
2998 res -= trafo_H_1mxt1px_prepend_one(buffer, arg) + trafo_H_1mxt1px_prepend_minusone(buffer, arg);
3002 } else if (parameter.op(0) == -1) {
3004 // leading negative one
3005 ex res = convert_H_to_zeta(parameter);
3006 map_trafo_H_1mxt1px recursion;
3007 ex buffer = recursion(H(newparameter, arg).hold());
3008 if (is_a<add>(buffer)) {
3009 for (int i=0; i<buffer.nops(); i++) {
3010 res -= trafo_H_1mxt1px_prepend_minusone(buffer.op(i), arg);
3013 res -= trafo_H_1mxt1px_prepend_minusone(buffer, arg);
3020 map_trafo_H_1mxt1px recursion;
3021 map_trafo_H_mult unify;
3022 ex res = H(lst(1), arg).hold() * H(newparameter, arg).hold();
3024 while (parameter.op(firstzero) == 1) {
3027 for (int i=firstzero-1; i<parameter.nops()-1; i++) {
3031 newparameter.append(parameter[j+1]);
3033 newparameter.append(1);
3034 for (; j<parameter.nops()-1; j++) {
3035 newparameter.append(parameter[j+1]);
3037 res -= H(newparameter, arg).hold();
3039 res = recursion(res).expand() / firstzero;
3051 // do the actual summation.
3052 cln::cl_N H_do_sum(const std::vector<int>& m, const cln::cl_N& x)
3054 const int j = m.size();
3056 std::vector<cln::cl_N> t(j);
3058 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
3059 cln::cl_N factor = cln::expt(x, j) * one;
3065 t[j-1] = t[j-1] + 1 / cln::expt(cln::cl_I(q),m[j-1]);
3066 for (int k=j-2; k>=1; k--) {
3067 t[k] = t[k] + t[k+1] / cln::expt(cln::cl_I(q+j-1-k), m[k]);
3069 t[0] = t[0] + t[1] * factor / cln::expt(cln::cl_I(q+j-1), m[0]);
3070 factor = factor * x;
3071 } while (t[0] != t0buf);
3077 } // end of anonymous namespace
3080 //////////////////////////////////////////////////////////////////////
3082 // Harmonic polylogarithm H(m,x)
3086 //////////////////////////////////////////////////////////////////////
3089 static ex H_evalf(const ex& x1, const ex& x2)
3091 if (is_a<lst>(x1)) {
3094 if (is_a<numeric>(x2)) {
3095 x = ex_to<numeric>(x2).to_cl_N();
3097 ex x2_val = x2.evalf();
3098 if (is_a<numeric>(x2_val)) {
3099 x = ex_to<numeric>(x2_val).to_cl_N();
3103 for (int i=0; i<x1.nops(); i++) {
3104 if (!x1.op(i).info(info_flags::integer)) {
3105 return H(x1, x2).hold();
3108 if (x1.nops() < 1) {
3109 return H(x1, x2).hold();
3112 const lst& morg = ex_to<lst>(x1);
3113 // remove trailing zeros ...
3114 if (*(--morg.end()) == 0) {
3115 symbol xtemp("xtemp");
3116 map_trafo_H_reduce_trailing_zeros filter;
3117 return filter(H(x1, xtemp).hold()).subs(xtemp==x2).evalf();
3119 // ... and expand parameter notation
3120 bool has_minus_one = false;
3122 for (lst::const_iterator it = morg.begin(); it != morg.end(); it++) {
3124 for (ex count=*it-1; count > 0; count--) {
3128 } else if (*it <= -1) {
3129 for (ex count=*it+1; count < 0; count++) {
3133 has_minus_one = true;
3140 if (cln::abs(x) < 0.95) {
3144 if (convert_parameter_H_to_Li(m, m_lst, s_lst, pf)) {
3145 // negative parameters -> s_lst is filled
3146 std::vector<int> m_int;
3147 std::vector<cln::cl_N> x_cln;
3148 for (lst::const_iterator it_int = m_lst.begin(), it_cln = s_lst.begin();
3149 it_int != m_lst.end(); it_int++, it_cln++) {
3150 m_int.push_back(ex_to<numeric>(*it_int).to_int());
3151 x_cln.push_back(ex_to<numeric>(*it_cln).to_cl_N());
3153 x_cln.front() = x_cln.front() * x;
3154 return pf * numeric(multipleLi_do_sum(m_int, x_cln));
3156 // only positive parameters
3158 if (m_lst.nops() == 1) {
3159 return Li(m_lst.op(0), x2).evalf();
3161 std::vector<int> m_int;
3162 for (lst::const_iterator it = m_lst.begin(); it != m_lst.end(); it++) {
3163 m_int.push_back(ex_to<numeric>(*it).to_int());
3165 return numeric(H_do_sum(m_int, x));
3169 symbol xtemp("xtemp");
3172 // ensure that the realpart of the argument is positive
3173 if (cln::realpart(x) < 0) {
3175 for (int i=0; i<m.nops(); i++) {
3177 m.let_op(i) = -m.op(i);
3184 if (cln::abs(x) >= 2.0) {
3185 map_trafo_H_1overx trafo;
3186 res *= trafo(H(m, xtemp));
3187 if (cln::imagpart(x) <= 0) {
3188 res = res.subs(H_polesign == -I*Pi);
3190 res = res.subs(H_polesign == I*Pi);
3192 return res.subs(xtemp == numeric(x)).evalf();
3195 // check transformations for 0.95 <= |x| < 2.0
3197 // |(1-x)/(1+x)| < 0.9 -> circular area with center=9.53+0i and radius=9.47
3198 if (cln::abs(x-9.53) <= 9.47) {
3200 map_trafo_H_1mxt1px trafo;
3201 res *= trafo(H(m, xtemp));
3204 if (has_minus_one) {
3205 map_trafo_H_convert_to_Li filter;
3206 return filter(H(m, numeric(x)).hold()).evalf();
3208 map_trafo_H_1mx trafo;
3209 res *= trafo(H(m, xtemp));
3212 return res.subs(xtemp == numeric(x)).evalf();
3215 return H(x1,x2).hold();
3219 static ex H_eval(const ex& m_, const ex& x)
3222 if (is_a<lst>(m_)) {
3227 if (m.nops() == 0) {
3235 if (*m.begin() > _ex1) {
3241 } else if (*m.begin() < _ex_1) {
3247 } else if (*m.begin() == _ex0) {
3254 for (lst::const_iterator it = ++m.begin(); it != m.end(); it++) {
3255 if ((*it).info(info_flags::integer)) {
3266 } else if (*it < _ex_1) {
3286 } else if (step == 1) {
3298 // if some m_i is not an integer
3299 return H(m_, x).hold();
3302 if ((x == _ex1) && (*(--m.end()) != _ex0)) {
3303 return convert_H_to_zeta(m);
3309 return H(m_, x).hold();
3311 return pow(log(x), m.nops()) / factorial(m.nops());
3314 return pow(-pos1*log(1-pos1*x), m.nops()) / factorial(m.nops());
3316 } else if ((step == 1) && (pos1 == _ex0)){
3321 return pow(-1, p) * S(n, p, -x);
3327 if (x.info(info_flags::numeric) && (!x.info(info_flags::crational))) {
3328 return H(m_, x).evalf();
3330 return H(m_, x).hold();
3334 static ex H_series(const ex& m, const ex& x, const relational& rel, int order, unsigned options)
3337 seq.push_back(expair(H(m, x), 0));
3338 return pseries(rel, seq);
3342 static ex H_deriv(const ex& m_, const ex& x, unsigned deriv_param)
3344 GINAC_ASSERT(deriv_param < 2);
3345 if (deriv_param == 0) {
3349 if (is_a<lst>(m_)) {
3365 return 1/(1-x) * H(m, x);
3366 } else if (mb == _ex_1) {
3367 return 1/(1+x) * H(m, x);
3374 static void H_print_latex(const ex& m_, const ex& x, const print_context& c)
3377 if (is_a<lst>(m_)) {
3382 c.s << "\\mbox{H}_{";
3383 lst::const_iterator itm = m.begin();
3386 for (; itm != m.end(); itm++) {
3396 REGISTER_FUNCTION(H,
3397 evalf_func(H_evalf).
3399 series_func(H_series).
3400 derivative_func(H_deriv).
3401 print_func<print_latex>(H_print_latex).
3402 do_not_evalf_params());
3405 // takes a parameter list for H and returns an expression with corresponding multiple polylogarithms
3406 ex convert_H_to_Li(const ex& m, const ex& x)
3408 map_trafo_H_reduce_trailing_zeros filter;
3409 map_trafo_H_convert_to_Li filter2;
3411 return filter2(filter(H(m, x).hold()));
3413 return filter2(filter(H(lst(m), x).hold()));
3418 //////////////////////////////////////////////////////////////////////
3420 // Multiple zeta values zeta(x) and zeta(x,s)
3424 //////////////////////////////////////////////////////////////////////
3427 // anonymous namespace for helper functions
3431 // parameters and data for [Cra] algorithm
3432 const cln::cl_N lambda = cln::cl_N("319/320");
3434 void halfcyclic_convolute(const std::vector<cln::cl_N>& a, const std::vector<cln::cl_N>& b, std::vector<cln::cl_N>& c)
3436 const int size = a.size();
3437 for (int n=0; n<size; n++) {
3439 for (int m=0; m<=n; m++) {
3440 c[n] = c[n] + a[m]*b[n-m];
3447 static void initcX(std::vector<cln::cl_N>& crX,
3448 const std::vector<int>& s,
3451 std::vector<cln::cl_N> crB(L2 + 1);
3452 for (int i=0; i<=L2; i++)
3453 crB[i] = bernoulli(i).to_cl_N() / cln::factorial(i);
3457 std::vector<std::vector<cln::cl_N> > crG(s.size() - 1, std::vector<cln::cl_N>(L2 + 1));
3458 for (int m=0; m < s.size() - 1; m++) {
3461 for (int i = 0; i <= L2; i++)
3462 crG[m][i] = cln::factorial(i + Sm - m - 2) / cln::factorial(i + Smp1 - m - 2);
3467 for (std::size_t m = 0; m < s.size() - 1; m++) {
3468 std::vector<cln::cl_N> Xbuf(L2 + 1);
3469 for (int i = 0; i <= L2; i++)
3470 Xbuf[i] = crX[i] * crG[m][i];
3472 halfcyclic_convolute(Xbuf, crB, crX);
3478 static cln::cl_N crandall_Y_loop(const cln::cl_N& Sqk,
3479 const std::vector<cln::cl_N>& crX)
3481 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
3482 cln::cl_N factor = cln::expt(lambda, Sqk);
3483 cln::cl_N res = factor / Sqk * crX[0] * one;
3488 factor = factor * lambda;
3490 res = res + crX[N] * factor / (N+Sqk);
3491 } while ((res != resbuf) || cln::zerop(crX[N]));
3497 static void calc_f(std::vector<std::vector<cln::cl_N> >& f_kj,
3498 const int maxr, const int L1)
3500 cln::cl_N t0, t1, t2, t3, t4;
3502 std::vector<std::vector<cln::cl_N> >::iterator it = f_kj.begin();
3503 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
3505 t0 = cln::exp(-lambda);
3507 for (k=1; k<=L1; k++) {
3510 for (j=1; j<=maxr; j++) {
3513 for (i=2; i<=j; i++) {
3517 (*it).push_back(t2 * t3 * cln::expt(cln::cl_I(k),-j) * one);
3525 static cln::cl_N crandall_Z(const std::vector<int>& s,
3526 const std::vector<std::vector<cln::cl_N> >& f_kj)
3528 const int j = s.size();
3537 t0 = t0 + f_kj[q+j-2][s[0]-1];
3538 } while (t0 != t0buf);
3540 return t0 / cln::factorial(s[0]-1);
3543 std::vector<cln::cl_N> t(j);
3550 t[j-1] = t[j-1] + 1 / cln::expt(cln::cl_I(q),s[j-1]);
3551 for (int k=j-2; k>=1; k--) {
3552 t[k] = t[k] + t[k+1] / cln::expt(cln::cl_I(q+j-1-k), s[k]);
3554 t[0] = t[0] + t[1] * f_kj[q+j-2][s[0]-1];
3555 } while (t[0] != t0buf);
3557 return t[0] / cln::factorial(s[0]-1);
3562 cln::cl_N zeta_do_sum_Crandall(const std::vector<int>& s)
3564 std::vector<int> r = s;
3565 const int j = r.size();
3569 // decide on maximal size of f_kj for crandall_Z
3573 L1 = Digits * 3 + j*2;
3577 // decide on maximal size of crX for crandall_Y
3580 } else if (Digits < 86) {
3582 } else if (Digits < 192) {
3584 } else if (Digits < 394) {
3586 } else if (Digits < 808) {
3596 for (int i=0; i<j; i++) {
3603 std::vector<std::vector<cln::cl_N> > f_kj(L1);
3604 calc_f(f_kj, maxr, L1);
3606 const cln::cl_N r0factorial = cln::factorial(r[0]-1);
3608 std::vector<int> rz;
3611 for (int k=r.size()-1; k>0; k--) {
3613 rz.insert(rz.begin(), r.back());
3614 skp1buf = rz.front();
3618 std::vector<cln::cl_N> crX;
3621 for (int q=0; q<skp1buf; q++) {
3623 cln::cl_N pp1 = crandall_Y_loop(Srun+q-k, crX);
3624 cln::cl_N pp2 = crandall_Z(rz, f_kj);
3629 res = res - pp1 * pp2 / cln::factorial(q);
3631 res = res + pp1 * pp2 / cln::factorial(q);
3634 rz.front() = skp1buf;
3636 rz.insert(rz.begin(), r.back());
3638 std::vector<cln::cl_N> crX;
3639 initcX(crX, rz, L2);
3641 res = (res + crandall_Y_loop(S-j, crX)) / r0factorial
3642 + crandall_Z(rz, f_kj);
3648 cln::cl_N zeta_do_sum_simple(const std::vector<int>& r)
3650 const int j = r.size();
3652 // buffer for subsums
3653 std::vector<cln::cl_N> t(j);
3654 cln::cl_F one = cln::cl_float(1, cln::float_format(Digits));
3661 t[j-1] = t[j-1] + one / cln::expt(cln::cl_I(q),r[j-1]);
3662 for (int k=j-2; k>=0; k--) {
3663 t[k] = t[k] + one * t[k+1] / cln::expt(cln::cl_I(q+j-1-k), r[k]);
3665 } while (t[0] != t0buf);
3671 // does Hoelder convolution. see [BBB] (7.0)
3672 cln::cl_N zeta_do_Hoelder_convolution(const std::vector<int>& m_, const std::vector<int>& s_)
3674 // prepare parameters
3675 // holds Li arguments in [BBB] notation
3676 std::vector<int> s = s_;
3677 std::vector<int> m_p = m_;
3678 std::vector<int> m_q;
3679 // holds Li arguments in nested sums notation
3680 std::vector<cln::cl_N> s_p(s.size(), cln::cl_N(1));
3681 s_p[0] = s_p[0] * cln::cl_N("1/2");
3682 // convert notations
3684 for (int i=0; i<s_.size(); i++) {
3689 s[i] = sig * std::abs(s[i]);
3691 std::vector<cln::cl_N> s_q;
3692 cln::cl_N signum = 1;
3695 cln::cl_N res = multipleLi_do_sum(m_p, s_p);
3700 // change parameters
3701 if (s.front() > 0) {
3702 if (m_p.front() == 1) {
3703 m_p.erase(m_p.begin());
3704 s_p.erase(s_p.begin());
3705 if (s_p.size() > 0) {
3706 s_p.front() = s_p.front() * cln::cl_N("1/2");
3712 m_q.insert(m_q.begin(), 1);
3713 if (s_q.size() > 0) {
3714 s_q.front() = s_q.front() * 2;
3716 s_q.insert(s_q.begin(), cln::cl_N("1/2"));
3719 if (m_p.front() == 1) {
3720 m_p.erase(m_p.begin());
3721 cln::cl_N spbuf = s_p.front();
3722 s_p.erase(s_p.begin());
3723 if (s_p.size() > 0) {
3724 s_p.front() = s_p.front() * spbuf;
3727 m_q.insert(m_q.begin(), 1);
3728 if (s_q.size() > 0) {
3729 s_q.front() = s_q.front() * 4;
3731 s_q.insert(s_q.begin(), cln::cl_N("1/4"));
3735 m_q.insert(m_q.begin(), 1);
3736 if (s_q.size() > 0) {
3737 s_q.front() = s_q.front() * 2;
3739 s_q.insert(s_q.begin(), cln::cl_N("1/2"));
3744 if (m_p.size() == 0) break;
3746 res = res + signum * multipleLi_do_sum(m_p, s_p) * multipleLi_do_sum(m_q, s_q);
3751 res = res + signum * multipleLi_do_sum(m_q, s_q);
3757 } // end of anonymous namespace
3760 //////////////////////////////////////////////////////////////////////
3762 // Multiple zeta values zeta(x)
3766 //////////////////////////////////////////////////////////////////////
3769 static ex zeta1_evalf(const ex& x)
3771 if (is_exactly_a<lst>(x) && (x.nops()>1)) {
3773 // multiple zeta value
3774 const int count = x.nops();
3775 const lst& xlst = ex_to<lst>(x);
3776 std::vector<int> r(count);
3778 // check parameters and convert them
3779 lst::const_iterator it1 = xlst.begin();
3780 std::vector<int>::iterator it2 = r.begin();
3782 if (!(*it1).info(info_flags::posint)) {
3783 return zeta(x).hold();
3785 *it2 = ex_to<numeric>(*it1).to_int();
3788 } while (it2 != r.end());
3790 // check for divergence
3792 return zeta(x).hold();
3795 // decide on summation algorithm
3796 // this is still a bit clumsy
3797 int limit = (Digits>17) ? 10 : 6;
3798 if ((r[0] < limit) || ((count > 3) && (r[1] < limit/2))) {
3799 return numeric(zeta_do_sum_Crandall(r));
3801 return numeric(zeta_do_sum_simple(r));
3805 // single zeta value
3806 if (is_exactly_a<numeric>(x) && (x != 1)) {
3808 return zeta(ex_to<numeric>(x));
3809 } catch (const dunno &e) { }
3812 return zeta(x).hold();
3816 static ex zeta1_eval(const ex& m)
3818 if (is_exactly_a<lst>(m)) {
3819 if (m.nops() == 1) {
3820 return zeta(m.op(0));
3822 return zeta(m).hold();
3825 if (m.info(info_flags::numeric)) {
3826 const numeric& y = ex_to<numeric>(m);
3827 // trap integer arguments:
3828 if (y.is_integer()) {
3832 if (y.is_equal(*_num1_p)) {
3833 return zeta(m).hold();
3835 if (y.info(info_flags::posint)) {
3836 if (y.info(info_flags::odd)) {
3837 return zeta(m).hold();
3839 return abs(bernoulli(y)) * pow(Pi, y) * pow(*_num2_p, y-(*_num1_p)) / factorial(y);
3842 if (y.info(info_flags::odd)) {
3843 return -bernoulli((*_num1_p)-y) / ((*_num1_p)-y);
3850 if (y.info(info_flags::numeric) && !y.info(info_flags::crational)) {
3851 return zeta1_evalf(m);
3854 return zeta(m).hold();
3858 static ex zeta1_deriv(const ex& m, unsigned deriv_param)
3860 GINAC_ASSERT(deriv_param==0);
3862 if (is_exactly_a<lst>(m)) {
3865 return zetaderiv(_ex1, m);
3870 static void zeta1_print_latex(const ex& m_, const print_context& c)
3873 if (is_a<lst>(m_)) {
3874 const lst& m = ex_to<lst>(m_);
3875 lst::const_iterator it = m.begin();
3878 for (; it != m.end(); it++) {
3889 unsigned zeta1_SERIAL::serial = function::register_new(function_options("zeta", 1).
3890 evalf_func(zeta1_evalf).
3891 eval_func(zeta1_eval).
3892 derivative_func(zeta1_deriv).
3893 print_func<print_latex>(zeta1_print_latex).
3894 do_not_evalf_params().
3898 //////////////////////////////////////////////////////////////////////
3900 // Alternating Euler sum zeta(x,s)
3904 //////////////////////////////////////////////////////////////////////
3907 static ex zeta2_evalf(const ex& x, const ex& s)
3909 if (is_exactly_a<lst>(x)) {
3911 // alternating Euler sum
3912 const int count = x.nops();
3913 const lst& xlst = ex_to<lst>(x);
3914 const lst& slst = ex_to<lst>(s);
3915 std::vector<int> xi(count);
3916 std::vector<int> si(count);
3918 // check parameters and convert them
3919 lst::const_iterator it_xread = xlst.begin();
3920 lst::const_iterator it_sread = slst.begin();
3921 std::vector<int>::iterator it_xwrite = xi.begin();
3922 std::vector<int>::iterator it_swrite = si.begin();
3924 if (!(*it_xread).info(info_flags::posint)) {
3925 return zeta(x, s).hold();
3927 *it_xwrite = ex_to<numeric>(*it_xread).to_int();
3928 if (*it_sread > 0) {
3937 } while (it_xwrite != xi.end());
3939 // check for divergence
3940 if ((xi[0] == 1) && (si[0] == 1)) {
3941 return zeta(x, s).hold();
3944 // use Hoelder convolution
3945 return numeric(zeta_do_Hoelder_convolution(xi, si));
3948 return zeta(x, s).hold();
3952 static ex zeta2_eval(const ex& m, const ex& s_)
3954 if (is_exactly_a<lst>(s_)) {
3955 const lst& s = ex_to<lst>(s_);
3956 for (lst::const_iterator it = s.begin(); it != s.end(); it++) {
3957 if ((*it).info(info_flags::positive)) {
3960 return zeta(m, s_).hold();
3963 } else if (s_.info(info_flags::positive)) {
3967 return zeta(m, s_).hold();
3971 static ex zeta2_deriv(const ex& m, const ex& s, unsigned deriv_param)
3973 GINAC_ASSERT(deriv_param==0);
3975 if (is_exactly_a<lst>(m)) {
3978 if ((is_exactly_a<lst>(s) && s.op(0).info(info_flags::positive)) || s.info(info_flags::positive)) {
3979 return zetaderiv(_ex1, m);
3986 static void zeta2_print_latex(const ex& m_, const ex& s_, const print_context& c)
3989 if (is_a<lst>(m_)) {
3995 if (is_a<lst>(s_)) {
4001 lst::const_iterator itm = m.begin();
4002 lst::const_iterator its = s.begin();
4004 c.s << "\\overline{";
4012 for (; itm != m.end(); itm++, its++) {
4015 c.s << "\\overline{";
4026 unsigned zeta2_SERIAL::serial = function::register_new(function_options("zeta", 2).
4027 evalf_func(zeta2_evalf).
4028 eval_func(zeta2_eval).
4029 derivative_func(zeta2_deriv).
4030 print_func<print_latex>(zeta2_print_latex).
4031 do_not_evalf_params().
4035 } // namespace GiNaC