X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Finifcns.cpp;h=e2a09b161ccf95ad01e3f95f07b823b79d2b2e54;hp=5ebd3d02139b153efa647263a232b956fb7bf5cc;hb=8cffcdf13d817a47f217f1a1043317d95969e070;hpb=dc2510946d9ce577aab2bd3e5d2f62c50d3faa30 diff --git a/ginac/inifcns.cpp b/ginac/inifcns.cpp index 5ebd3d02..e2a09b16 100644 --- a/ginac/inifcns.cpp +++ b/ginac/inifcns.cpp @@ -3,7 +3,7 @@ * Implementation of GiNaC's initially known functions. */ /* - * GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany + * GiNaC Copyright (C) 1999-2019 Johannes Gutenberg University Mainz, Germany * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -17,27 +17,241 @@ * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ -#include -#include - #include "inifcns.h" #include "ex.h" #include "constant.h" #include "lst.h" +#include "fderivative.h" #include "matrix.h" #include "mul.h" #include "power.h" +#include "operators.h" #include "relational.h" #include "pseries.h" #include "symbol.h" #include "symmetry.h" #include "utils.h" +#include +#include + namespace GiNaC { +////////// +// complex conjugate +////////// + +static ex conjugate_evalf(const ex & arg) +{ + if (is_exactly_a(arg)) { + return ex_to(arg).conjugate(); + } + return conjugate_function(arg).hold(); +} + +static ex conjugate_eval(const ex & arg) +{ + return arg.conjugate(); +} + +static void conjugate_print_latex(const ex & arg, const print_context & c) +{ + c.s << "\\bar{"; arg.print(c); c.s << "}"; +} + +static ex conjugate_conjugate(const ex & arg) +{ + return arg; +} + +// If x is real then U.diff(x)-I*V.diff(x) represents both conjugate(U+I*V).diff(x) +// and conjugate((U+I*V).diff(x)) +static ex conjugate_expl_derivative(const ex & arg, const symbol & s) +{ + if (s.info(info_flags::real)) + return conjugate(arg.diff(s)); + else { + exvector vec_arg; + vec_arg.push_back(arg); + return fderivative(ex_to(conjugate(arg)).get_serial(),0,vec_arg).hold()*arg.diff(s); + } +} + +static ex conjugate_real_part(const ex & arg) +{ + return arg.real_part(); +} + +static ex conjugate_imag_part(const ex & arg) +{ + return -arg.imag_part(); +} + +static bool func_arg_info(const ex & arg, unsigned inf) +{ + // for some functions we can return the info() of its argument + // (think of conjugate()) + switch (inf) { + case info_flags::polynomial: + case info_flags::integer_polynomial: + case info_flags::cinteger_polynomial: + case info_flags::rational_polynomial: + case info_flags::real: + case info_flags::rational: + case info_flags::integer: + case info_flags::crational: + case info_flags::cinteger: + case info_flags::even: + case info_flags::odd: + case info_flags::prime: + case info_flags::crational_polynomial: + case info_flags::rational_function: + case info_flags::positive: + case info_flags::negative: + case info_flags::nonnegative: + case info_flags::posint: + case info_flags::negint: + case info_flags::nonnegint: + case info_flags::has_indices: + return arg.info(inf); + } + return false; +} + +static bool conjugate_info(const ex & arg, unsigned inf) +{ + return func_arg_info(arg, inf); +} + +REGISTER_FUNCTION(conjugate_function, eval_func(conjugate_eval). + evalf_func(conjugate_evalf). + expl_derivative_func(conjugate_expl_derivative). + info_func(conjugate_info). + print_func(conjugate_print_latex). + conjugate_func(conjugate_conjugate). + real_part_func(conjugate_real_part). + imag_part_func(conjugate_imag_part). + set_name("conjugate","conjugate")); + +////////// +// real part +////////// + +static ex real_part_evalf(const ex & arg) +{ + if (is_exactly_a(arg)) { + return ex_to(arg).real(); + } + return real_part_function(arg).hold(); +} + +static ex real_part_eval(const ex & arg) +{ + return arg.real_part(); +} + +static void real_part_print_latex(const ex & arg, const print_context & c) +{ + c.s << "\\Re"; arg.print(c); c.s << ""; +} + +static ex real_part_conjugate(const ex & arg) +{ + return real_part_function(arg).hold(); +} + +static ex real_part_real_part(const ex & arg) +{ + return real_part_function(arg).hold(); +} + +static ex real_part_imag_part(const ex & arg) +{ + return 0; +} + +// If x is real then Re(e).diff(x) is equal to Re(e.diff(x)) +static ex real_part_expl_derivative(const ex & arg, const symbol & s) +{ + if (s.info(info_flags::real)) + return real_part_function(arg.diff(s)); + else { + exvector vec_arg; + vec_arg.push_back(arg); + return fderivative(ex_to(real_part(arg)).get_serial(),0,vec_arg).hold()*arg.diff(s); + } +} + +REGISTER_FUNCTION(real_part_function, eval_func(real_part_eval). + evalf_func(real_part_evalf). + expl_derivative_func(real_part_expl_derivative). + print_func(real_part_print_latex). + conjugate_func(real_part_conjugate). + real_part_func(real_part_real_part). + imag_part_func(real_part_imag_part). + set_name("real_part","real_part")); + +////////// +// imag part +////////// + +static ex imag_part_evalf(const ex & arg) +{ + if (is_exactly_a(arg)) { + return ex_to(arg).imag(); + } + return imag_part_function(arg).hold(); +} + +static ex imag_part_eval(const ex & arg) +{ + return arg.imag_part(); +} + +static void imag_part_print_latex(const ex & arg, const print_context & c) +{ + c.s << "\\Im"; arg.print(c); c.s << ""; +} + +static ex imag_part_conjugate(const ex & arg) +{ + return imag_part_function(arg).hold(); +} + +static ex imag_part_real_part(const ex & arg) +{ + return imag_part_function(arg).hold(); +} + +static ex imag_part_imag_part(const ex & arg) +{ + return 0; +} + +// If x is real then Im(e).diff(x) is equal to Im(e.diff(x)) +static ex imag_part_expl_derivative(const ex & arg, const symbol & s) +{ + if (s.info(info_flags::real)) + return imag_part_function(arg.diff(s)); + else { + exvector vec_arg; + vec_arg.push_back(arg); + return fderivative(ex_to(imag_part(arg)).get_serial(),0,vec_arg).hold()*arg.diff(s); + } +} + +REGISTER_FUNCTION(imag_part_function, eval_func(imag_part_eval). + evalf_func(imag_part_evalf). + expl_derivative_func(imag_part_expl_derivative). + print_func(imag_part_print_latex). + conjugate_func(imag_part_conjugate). + real_part_func(imag_part_real_part). + imag_part_func(imag_part_imag_part). + set_name("imag_part","imag_part")); + ////////// // absolute value ////////// @@ -52,15 +266,217 @@ static ex abs_evalf(const ex & arg) static ex abs_eval(const ex & arg) { - if (is_ex_exactly_of_type(arg, numeric)) + if (is_exactly_a(arg)) return abs(ex_to(arg)); + + if (arg.info(info_flags::nonnegative)) + return arg; + + if (arg.info(info_flags::negative) || (-arg).info(info_flags::nonnegative)) + return -arg; + + if (is_ex_the_function(arg, abs)) + return arg; + + if (is_ex_the_function(arg, exp)) + return exp(arg.op(0).real_part()); + + if (is_exactly_a(arg)) { + const ex& base = arg.op(0); + const ex& exponent = arg.op(1); + if (base.info(info_flags::positive) || exponent.info(info_flags::real)) + return pow(abs(base), exponent.real_part()); + } + + if (is_ex_the_function(arg, conjugate_function)) + return abs(arg.op(0)); + + if (is_ex_the_function(arg, step)) + return arg; + + return abs(arg).hold(); +} + +static ex abs_expand(const ex & arg, unsigned options) +{ + if ((options & expand_options::expand_transcendental) + && is_exactly_a(arg)) { + exvector prodseq; + prodseq.reserve(arg.nops()); + for (const_iterator i = arg.begin(); i != arg.end(); ++i) { + if (options & expand_options::expand_function_args) + prodseq.push_back(abs(i->expand(options))); + else + prodseq.push_back(abs(*i)); + } + return dynallocate(prodseq).setflag(status_flags::expanded); + } + + if (options & expand_options::expand_function_args) + return abs(arg.expand(options)).hold(); else return abs(arg).hold(); } +static ex abs_expl_derivative(const ex & arg, const symbol & s) +{ + ex diff_arg = arg.diff(s); + return (diff_arg*arg.conjugate()+arg*diff_arg.conjugate())/2/abs(arg); +} + +static void abs_print_latex(const ex & arg, const print_context & c) +{ + c.s << "{|"; arg.print(c); c.s << "|}"; +} + +static void abs_print_csrc_float(const ex & arg, const print_context & c) +{ + c.s << "fabs("; arg.print(c); c.s << ")"; +} + +static ex abs_conjugate(const ex & arg) +{ + return abs(arg).hold(); +} + +static ex abs_real_part(const ex & arg) +{ + return abs(arg).hold(); +} + +static ex abs_imag_part(const ex& arg) +{ + return 0; +} + +static ex abs_power(const ex & arg, const ex & exp) +{ + if ((is_a(exp) && ex_to(exp).is_even()) || exp.info(info_flags::even)) { + if (arg.info(info_flags::real) || arg.is_equal(arg.conjugate())) + return pow(arg, exp); + else + return pow(arg, exp/2) * pow(arg.conjugate(), exp/2); + } else + return power(abs(arg), exp).hold(); +} + +bool abs_info(const ex & arg, unsigned inf) +{ + switch (inf) { + case info_flags::integer: + case info_flags::even: + case info_flags::odd: + case info_flags::prime: + return arg.info(inf); + case info_flags::nonnegint: + return arg.info(info_flags::integer); + case info_flags::nonnegative: + case info_flags::real: + return true; + case info_flags::negative: + return false; + case info_flags::positive: + return arg.info(info_flags::positive) || arg.info(info_flags::negative); + case info_flags::has_indices: { + if (arg.info(info_flags::has_indices)) + return true; + else + return false; + } + } + return false; +} + REGISTER_FUNCTION(abs, eval_func(abs_eval). - evalf_func(abs_evalf)); + evalf_func(abs_evalf). + expand_func(abs_expand). + expl_derivative_func(abs_expl_derivative). + info_func(abs_info). + print_func(abs_print_latex). + print_func(abs_print_csrc_float). + print_func(abs_print_csrc_float). + conjugate_func(abs_conjugate). + real_part_func(abs_real_part). + imag_part_func(abs_imag_part). + power_func(abs_power)); +////////// +// Step function +////////// + +static ex step_evalf(const ex & arg) +{ + if (is_exactly_a(arg)) + return step(ex_to(arg)); + + return step(arg).hold(); +} + +static ex step_eval(const ex & arg) +{ + if (is_exactly_a(arg)) + return step(ex_to(arg)); + + else if (is_exactly_a(arg) && + is_exactly_a(arg.op(arg.nops()-1))) { + numeric oc = ex_to(arg.op(arg.nops()-1)); + if (oc.is_real()) { + if (oc > 0) + // step(42*x) -> step(x) + return step(arg/oc).hold(); + else + // step(-42*x) -> step(-x) + return step(-arg/oc).hold(); + } + if (oc.real().is_zero()) { + if (oc.imag() > 0) + // step(42*I*x) -> step(I*x) + return step(I*arg/oc).hold(); + else + // step(-42*I*x) -> step(-I*x) + return step(-I*arg/oc).hold(); + } + } + + return step(arg).hold(); +} + +static ex step_series(const ex & arg, + const relational & rel, + int order, + unsigned options) +{ + const ex arg_pt = arg.subs(rel, subs_options::no_pattern); + if (arg_pt.info(info_flags::numeric) + && ex_to(arg_pt).real().is_zero() + && !(options & series_options::suppress_branchcut)) + throw (std::domain_error("step_series(): on imaginary axis")); + + epvector seq { expair(step(arg_pt), _ex0) }; + return pseries(rel, std::move(seq)); +} + +static ex step_conjugate(const ex& arg) +{ + return step(arg).hold(); +} + +static ex step_real_part(const ex& arg) +{ + return step(arg).hold(); +} + +static ex step_imag_part(const ex& arg) +{ + return 0; +} + +REGISTER_FUNCTION(step, eval_func(step_eval). + evalf_func(step_evalf). + series_func(step_series). + conjugate_func(step_conjugate). + real_part_func(step_real_part). + imag_part_func(step_imag_part)); ////////// // Complex sign @@ -76,11 +492,11 @@ static ex csgn_evalf(const ex & arg) static ex csgn_eval(const ex & arg) { - if (is_ex_exactly_of_type(arg, numeric)) + if (is_exactly_a(arg)) return csgn(ex_to(arg)); - else if (is_ex_of_type(arg, mul) && - is_ex_of_type(arg.op(arg.nops()-1),numeric)) { + else if (is_exactly_a(arg) && + is_exactly_a(arg.op(arg.nops()-1))) { numeric oc = ex_to(arg.op(arg.nops()-1)); if (oc.is_real()) { if (oc > 0) @@ -108,24 +524,56 @@ static ex csgn_series(const ex & arg, int order, unsigned options) { - const ex arg_pt = arg.subs(rel); + const ex arg_pt = arg.subs(rel, subs_options::no_pattern); if (arg_pt.info(info_flags::numeric) && ex_to(arg_pt).real().is_zero() && !(options & series_options::suppress_branchcut)) throw (std::domain_error("csgn_series(): on imaginary axis")); - epvector seq; - seq.push_back(expair(csgn(arg_pt), _ex0())); - return pseries(rel,seq); + epvector seq { expair(csgn(arg_pt), _ex0) }; + return pseries(rel, std::move(seq)); +} + +static ex csgn_conjugate(const ex& arg) +{ + return csgn(arg).hold(); +} + +static ex csgn_real_part(const ex& arg) +{ + return csgn(arg).hold(); +} + +static ex csgn_imag_part(const ex& arg) +{ + return 0; +} + +static ex csgn_power(const ex & arg, const ex & exp) +{ + if (is_a(exp) && exp.info(info_flags::positive) && ex_to(exp).is_integer()) { + if (ex_to(exp).is_odd()) + return csgn(arg).hold(); + else + return power(csgn(arg), _ex2).hold(); + } else + return power(csgn(arg), exp).hold(); } + REGISTER_FUNCTION(csgn, eval_func(csgn_eval). evalf_func(csgn_evalf). - series_func(csgn_series)); + series_func(csgn_series). + conjugate_func(csgn_conjugate). + real_part_func(csgn_real_part). + imag_part_func(csgn_imag_part). + power_func(csgn_power)); ////////// // Eta function: eta(x,y) == log(x*y) - log(x) - log(y). +// This function is closely related to the unwinding number K, sometimes found +// in modern literature: K(z) == (z-log(exp(z)))/(2*Pi*I). ////////// static ex eta_evalf(const ex &x, const ex &y) @@ -133,7 +581,7 @@ static ex eta_evalf(const ex &x, const ex &y) // It seems like we basically have to replicate the eval function here, // since the expression might not be fully evaluated yet. if (x.info(info_flags::positive) || y.info(info_flags::positive)) - return _ex0(); + return _ex0; if (x.info(info_flags::numeric) && y.info(info_flags::numeric)) { const numeric nx = ex_to(x); @@ -157,7 +605,7 @@ static ex eta_eval(const ex &x, const ex &y) { // trivial: eta(x,c) -> 0 if c is real and positive if (x.info(info_flags::positive) || y.info(info_flags::positive)) - return _ex0(); + return _ex0; if (x.info(info_flags::numeric) && y.info(info_flags::numeric)) { // don't call eta_evalf here because it would call Pi.evalf()! @@ -183,22 +631,39 @@ static ex eta_series(const ex & x, const ex & y, int order, unsigned options) { - const ex x_pt = x.subs(rel); - const ex y_pt = y.subs(rel); + const ex x_pt = x.subs(rel, subs_options::no_pattern); + const ex y_pt = y.subs(rel, subs_options::no_pattern); if ((x_pt.info(info_flags::numeric) && x_pt.info(info_flags::negative)) || (y_pt.info(info_flags::numeric) && y_pt.info(info_flags::negative)) || ((x_pt*y_pt).info(info_flags::numeric) && (x_pt*y_pt).info(info_flags::negative))) throw (std::domain_error("eta_series(): on discontinuity")); - epvector seq; - seq.push_back(expair(eta(x_pt,y_pt), _ex0())); - return pseries(rel,seq); + epvector seq { expair(eta(x_pt,y_pt), _ex0) }; + return pseries(rel, std::move(seq)); +} + +static ex eta_conjugate(const ex & x, const ex & y) +{ + return -eta(x, y).hold(); +} + +static ex eta_real_part(const ex & x, const ex & y) +{ + return 0; +} + +static ex eta_imag_part(const ex & x, const ex & y) +{ + return -I*eta(x, y).hold(); } REGISTER_FUNCTION(eta, eval_func(eta_eval). evalf_func(eta_evalf). series_func(eta_series). latex_name("\\eta"). - set_symmetry(sy_symm(0, 1))); + set_symmetry(sy_symm(0, 1)). + conjugate_func(eta_conjugate). + real_part_func(eta_real_part). + imag_part_func(eta_imag_part)); ////////// @@ -218,22 +683,22 @@ static ex Li2_eval(const ex & x) if (x.info(info_flags::numeric)) { // Li2(0) -> 0 if (x.is_zero()) - return _ex0(); + return _ex0; // Li2(1) -> Pi^2/6 - if (x.is_equal(_ex1())) - return power(Pi,_ex2())/_ex6(); + if (x.is_equal(_ex1)) + return power(Pi,_ex2)/_ex6; // Li2(1/2) -> Pi^2/12 - log(2)^2/2 - if (x.is_equal(_ex1_2())) - return power(Pi,_ex2())/_ex12() + power(log(_ex2()),_ex2())*_ex_1_2(); + if (x.is_equal(_ex1_2)) + return power(Pi,_ex2)/_ex12 + power(log(_ex2),_ex2)*_ex_1_2; // Li2(-1) -> -Pi^2/12 - if (x.is_equal(_ex_1())) - return -power(Pi,_ex2())/_ex12(); + if (x.is_equal(_ex_1)) + return -power(Pi,_ex2)/_ex12; // Li2(I) -> -Pi^2/48+Catalan*I if (x.is_equal(I)) - return power(Pi,_ex2())/_ex_48() + Catalan*I; + return power(Pi,_ex2)/_ex_48 + Catalan*I; // Li2(-I) -> -Pi^2/48-Catalan*I if (x.is_equal(-I)) - return power(Pi,_ex2())/_ex_48() - Catalan*I; + return power(Pi,_ex2)/_ex_48 - Catalan*I; // Li2(float) if (!x.info(info_flags::crational)) return Li2(ex_to(x)); @@ -247,12 +712,12 @@ static ex Li2_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx Li2(x) -> -log(1-x)/x - return -log(_ex1()-x)/x; + return -log(_ex1-x)/x; } static ex Li2_series(const ex &x, const relational &rel, int order, unsigned options) { - const ex x_pt = x.subs(rel); + const ex x_pt = x.subs(rel, subs_options::no_pattern); if (x_pt.info(info_flags::numeric)) { // First special case: x==0 (derivatives have poles) if (x_pt.is_zero()) { @@ -272,13 +737,12 @@ static ex Li2_series(const ex &x, const relational &rel, int order, unsigned opt ex ser; // manually construct the primitive expansion for (int i=1; i(rel.lhs().bp); + const symbol &s = ex_to(rel.lhs()); const ex point = rel.rhs(); const symbol foo; epvector seq; // zeroth order term: - seq.push_back(expair(Li2(x_pt), _ex0())); + seq.push_back(expair(Li2(x_pt), _ex0)); // compute the intermediate terms: - ex replarg = series(Li2(x), *s==foo, order); - for (unsigned i=1; i(x) && + (!x.imag_part().is_zero() || x < *_num1_p)) { + return Li2(x.conjugate()); + } + return conjugate_function(Li2(x)).hold(); +} + REGISTER_FUNCTION(Li2, eval_func(Li2_eval). evalf_func(Li2_evalf). derivative_func(Li2_deriv). series_func(Li2_series). - latex_name("\\mbox{Li}_2")); + conjugate_func(Li2_conjugate). + latex_name("\\mathrm{Li}_2")); ////////// // trilogarithm @@ -350,7 +828,38 @@ static ex Li3_eval(const ex & x) } REGISTER_FUNCTION(Li3, eval_func(Li3_eval). - latex_name("\\mbox{Li}_3")); + latex_name("\\mathrm{Li}_3")); + +////////// +// Derivatives of Riemann's Zeta-function zetaderiv(0,x)==zeta(x) +////////// + +static ex zetaderiv_eval(const ex & n, const ex & x) +{ + if (n.info(info_flags::numeric)) { + // zetaderiv(0,x) -> zeta(x) + if (n.is_zero()) + return zeta(x).hold(); + } + + return zetaderiv(n, x).hold(); +} + +static ex zetaderiv_deriv(const ex & n, const ex & x, unsigned deriv_param) +{ + GINAC_ASSERT(deriv_param<2); + + if (deriv_param==0) { + // d/dn zeta(n,x) + throw(std::logic_error("cannot diff zetaderiv(n,x) with respect to n")); + } + // d/dx psi(n,x) + return zetaderiv(n+1,x); +} + +REGISTER_FUNCTION(zetaderiv, eval_func(zetaderiv_eval). + derivative_func(zetaderiv_deriv). + latex_name("\\zeta^\\prime")); ////////// // factorial @@ -363,14 +872,45 @@ static ex factorial_evalf(const ex & x) static ex factorial_eval(const ex & x) { - if (is_ex_exactly_of_type(x, numeric)) + if (is_exactly_a(x)) return factorial(ex_to(x)); else return factorial(x).hold(); } +static void factorial_print_dflt_latex(const ex & x, const print_context & c) +{ + if (is_exactly_a(x) || + is_exactly_a(x) || + is_exactly_a(x)) { + x.print(c); c.s << "!"; + } else { + c.s << "("; x.print(c); c.s << ")!"; + } +} + +static ex factorial_conjugate(const ex & x) +{ + return factorial(x).hold(); +} + +static ex factorial_real_part(const ex & x) +{ + return factorial(x).hold(); +} + +static ex factorial_imag_part(const ex & x) +{ + return 0; +} + REGISTER_FUNCTION(factorial, eval_func(factorial_eval). - evalf_func(factorial_evalf)); + evalf_func(factorial_evalf). + print_func(factorial_print_dflt_latex). + print_func(factorial_print_dflt_latex). + conjugate_func(factorial_conjugate). + real_part_func(factorial_real_part). + imag_part_func(factorial_imag_part)); ////////// // binomial @@ -381,16 +921,58 @@ static ex binomial_evalf(const ex & x, const ex & y) return binomial(x, y).hold(); } +static ex binomial_sym(const ex & x, const numeric & y) +{ + if (y.is_integer()) { + if (y.is_nonneg_integer()) { + const unsigned N = y.to_int(); + if (N == 0) return _ex1; + if (N == 1) return x; + ex t = x.expand(); + for (unsigned i = 2; i <= N; ++i) + t = (t * (x + i - y - 1)).expand() / i; + return t; + } else + return _ex0; + } + + return binomial(x, y).hold(); +} + static ex binomial_eval(const ex & x, const ex &y) { - if (is_ex_exactly_of_type(x, numeric) && is_ex_exactly_of_type(y, numeric)) - return binomial(ex_to(x), ex_to(y)); - else + if (is_exactly_a(y)) { + if (is_exactly_a(x) && ex_to(x).is_integer()) + return binomial(ex_to(x), ex_to(y)); + else + return binomial_sym(x, ex_to(y)); + } else return binomial(x, y).hold(); } +// At the moment the numeric evaluation of a binomial function always +// gives a real number, but if this would be implemented using the gamma +// function, also complex conjugation should be changed (or rather, deleted). +static ex binomial_conjugate(const ex & x, const ex & y) +{ + return binomial(x,y).hold(); +} + +static ex binomial_real_part(const ex & x, const ex & y) +{ + return binomial(x,y).hold(); +} + +static ex binomial_imag_part(const ex & x, const ex & y) +{ + return 0; +} + REGISTER_FUNCTION(binomial, eval_func(binomial_eval). - evalf_func(binomial_evalf)); + evalf_func(binomial_evalf). + conjugate_func(binomial_conjugate). + real_part_func(binomial_real_part). + imag_part_func(binomial_imag_part)); ////////// // Order term function (for truncated power series) @@ -398,17 +980,17 @@ REGISTER_FUNCTION(binomial, eval_func(binomial_eval). static ex Order_eval(const ex & x) { - if (is_ex_exactly_of_type(x, numeric)) { + if (is_exactly_a(x)) { // O(c) -> O(1) or 0 if (!x.is_zero()) - return Order(_ex1()).hold(); + return Order(_ex1).hold(); else - return _ex0(); - } else if (is_ex_exactly_of_type(x, mul)) { - mul *m = static_cast(x.bp); + return _ex0; + } else if (is_exactly_a(x)) { + const mul &m = ex_to(x); // O(c*expr) -> O(expr) - if (is_ex_exactly_of_type(m->op(m->nops() - 1), numeric)) - return Order(x / m->op(m->nops() - 1)).hold(); + if (is_exactly_a(m.op(m.nops() - 1))) + return Order(x / m.op(m.nops() - 1)).hold(); } return Order(x).hold(); } @@ -416,52 +998,93 @@ static ex Order_eval(const ex & x) static ex Order_series(const ex & x, const relational & r, int order, unsigned options) { // Just wrap the function into a pseries object - epvector new_seq; - GINAC_ASSERT(is_ex_exactly_of_type(r.lhs(),symbol)); - const symbol *s = static_cast(r.lhs().bp); - new_seq.push_back(expair(Order(_ex1()), numeric(std::min(x.ldegree(*s), order)))); - return pseries(r, new_seq); + GINAC_ASSERT(is_a(r.lhs())); + const symbol &s = ex_to(r.lhs()); + epvector new_seq { expair(Order(_ex1), numeric(std::min(x.ldegree(s), order))) }; + return pseries(r, std::move(new_seq)); +} + +static ex Order_conjugate(const ex & x) +{ + return Order(x).hold(); } -// Differentiation is handled in function::derivative because of its special requirements +static ex Order_real_part(const ex & x) +{ + return Order(x).hold(); +} + +static ex Order_imag_part(const ex & x) +{ + if(x.info(info_flags::real)) + return 0; + return Order(x).hold(); +} + +static ex Order_expl_derivative(const ex & arg, const symbol & s) +{ + return Order(arg.diff(s)); +} REGISTER_FUNCTION(Order, eval_func(Order_eval). series_func(Order_series). - latex_name("\\mathcal{O}")); + latex_name("\\mathcal{O}"). + expl_derivative_func(Order_expl_derivative). + conjugate_func(Order_conjugate). + real_part_func(Order_real_part). + imag_part_func(Order_imag_part)); ////////// // Solve linear system ////////// +static void insert_symbols(exset &es, const ex &e) +{ + if (is_a(e)) { + es.insert(e); + } else { + for (const ex &sube : e) { + insert_symbols(es, sube); + } + } +} + +static exset symbolset(const ex &e) +{ + exset s; + insert_symbols(s, e); + return s; +} + ex lsolve(const ex &eqns, const ex &symbols, unsigned options) { // solve a system of linear equations if (eqns.info(info_flags::relation_equal)) { if (!symbols.info(info_flags::symbol)) throw(std::invalid_argument("lsolve(): 2nd argument must be a symbol")); - const ex sol = lsolve(lst(eqns),lst(symbols)); + const ex sol = lsolve(lst{eqns}, lst{symbols}); GINAC_ASSERT(sol.nops()==1); - GINAC_ASSERT(is_ex_exactly_of_type(sol.op(0),relational)); + GINAC_ASSERT(is_exactly_a(sol.op(0))); return sol.op(0).op(1); // return rhs of first solution } // syntax checks - if (!eqns.info(info_flags::list)) { - throw(std::invalid_argument("lsolve(): 1st argument must be a list")); + if (!(eqns.info(info_flags::list) || eqns.info(info_flags::exprseq))) { + throw(std::invalid_argument("lsolve(): 1st argument must be a list, a sequence, or an equation")); } - for (unsigned i=0; i(symbols.op(c)),1); linpart -= co*symbols.op(c); sys(r,c) = co; @@ -483,11 +1108,13 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options) } // test if system is linear and fill vars matrix - for (unsigned i=0; i(f_in)) { + f = f_in.lhs()-f_in.rhs(); + } else { + f = f_in; + } + const ex fx_[2] = { f.subs(x==xx[0]).evalf(), + f.subs(x==xx[1]).evalf() }; + if (!is_a(fx_[0]) || !is_a(fx_[1])) { + throw std::runtime_error("fsolve(): function does not evaluate numerically"); + } + numeric fx[2] = { ex_to(fx_[0]), + ex_to(fx_[1]) }; + if (!fx[0].is_real() || !fx[1].is_real()) { + throw std::runtime_error("fsolve(): function evaluates to complex values at interval boundaries"); + } + if (fx[0]*fx[1]>=0) { + throw std::runtime_error("fsolve(): function does not change sign at interval boundaries"); + } + + // The Newton-Raphson method has quadratic convergence! Simply put, it + // replaces x with x-f(x)/f'(x) at each step. -f/f' is the delta: + const ex ff = normal(-f/f.diff(x)); + int side = 0; // Start at left interval limit. + numeric xxprev; + numeric fxprev; + do { + xxprev = xx[side]; + fxprev = fx[side]; + ex dx_ = ff.subs(x == xx[side]).evalf(); + if (!is_a(dx_)) + throw std::runtime_error("fsolve(): function derivative does not evaluate numerically"); + xx[side] += ex_to(dx_); + // Now check if Newton-Raphson method shot out of the interval + bool bad_shot = (side == 0 && xx[0] < xxprev) || + (side == 1 && xx[1] > xxprev) || xx[0] > xx[1]; + if (!bad_shot) { + // Compute f(x) only if new x is inside the interval. + // The function might be difficult to compute numerically + // or even ill defined outside the interval. Also it's + // a small optimization. + ex f_x = f.subs(x == xx[side]).evalf(); + if (!is_a(f_x)) + throw std::runtime_error("fsolve(): function does not evaluate numerically"); + fx[side] = ex_to(f_x); + } + if (bad_shot) { + // Oops, Newton-Raphson method shot out of the interval. + // Restore, and try again with the other side instead! + xx[side] = xxprev; + fx[side] = fxprev; + side = !side; + xxprev = xx[side]; + fxprev = fx[side]; + + ex dx_ = ff.subs(x == xx[side]).evalf(); + if (!is_a(dx_)) + throw std::runtime_error("fsolve(): function derivative does not evaluate numerically [2]"); + xx[side] += ex_to(dx_); + + ex f_x = f.subs(x==xx[side]).evalf(); + if (!is_a(f_x)) + throw std::runtime_error("fsolve(): function does not evaluate numerically [2]"); + fx[side] = ex_to(f_x); + } + if ((fx[side]<0 && fx[!side]<0) || (fx[side]>0 && fx[!side]>0)) { + // Oops, the root isn't bracketed any more. + // Restore, and perform a bisection! + xx[side] = xxprev; + fx[side] = fxprev; + + // Ah, the bisection! Bisections converge linearly. Unfortunately, + // they occur pretty often when Newton-Raphson arrives at an x too + // close to the result on one side of the interval and + // f(x-f(x)/f'(x)) turns out to have the same sign as f(x) due to + // precision errors! Recall that this function does not have a + // precision goal as one of its arguments but instead relies on + // x converging to a fixed point. We speed up the (safe but slow) + // bisection method by mixing in a dash of the (unsafer but faster) + // secant method: Instead of splitting the interval at the + // arithmetic mean (bisection), we split it nearer to the root as + // determined by the secant between the values xx[0] and xx[1]. + // Don't set the secant_weight to one because that could disturb + // the convergence in some corner cases! + constexpr double secant_weight = 0.984375; // == 63/64 < 1 + numeric xxmid = (1-secant_weight)*0.5*(xx[0]+xx[1]) + + secant_weight*(xx[0]+fx[0]*(xx[0]-xx[1])/(fx[1]-fx[0])); + ex fxmid_ = f.subs(x == xxmid).evalf(); + if (!is_a(fxmid_)) + throw std::runtime_error("fsolve(): function does not evaluate numerically [3]"); + numeric fxmid = ex_to(fxmid_); + if (fxmid.is_zero()) { + // Luck strikes... + return xxmid; + } + if ((fxmid<0 && fx[side]>0) || (fxmid>0 && fx[side]<0)) { + side = !side; + } + xxprev = xx[side]; + fxprev = fx[side]; + xx[side] = xxmid; + fx[side] = fxmid; + } + } while (xxprev!=xx[side]); + return xxprev; +} + + /* Force inclusion of functions from inifcns_gamma and inifcns_zeta * for static lib (so ginsh will see them). */ -unsigned force_include_tgamma = function_index_tgamma; -unsigned force_include_zeta1 = function_index_zeta1; +unsigned force_include_tgamma = tgamma_SERIAL::serial; +unsigned force_include_zeta1 = zeta1_SERIAL::serial; } // namespace GiNaC