* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#include <stdexcept>
#include <algorithm>
#include <map>
#include "constant.h"
#include "expairseq.h"
#include "fail.h"
-#include "indexed.h"
#include "inifcns.h"
#include "lst.h"
#include "mul.h"
-#include "ncmul.h"
#include "numeric.h"
#include "power.h"
#include "relational.h"
+#include "matrix.h"
#include "pseries.h"
#include "symbol.h"
#include "utils.h"
-#ifndef NO_NAMESPACE_GINAC
namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
// If comparing expressions (ex::compare()) is fast, you can set this to 1.
// Some routines like quo(), rem() and gcd() will then return a quick answer
/** Maximum of deg_a and deg_b (Used for sorting) */
int max_deg;
+ /** Maximum number of terms of leading coefficient of symbol in both polynomials */
+ int max_lcnops;
+
/** Commparison operator for sorting */
- bool operator<(const sym_desc &x) const {return max_deg < x.max_deg;}
+ bool operator<(const sym_desc &x) const
+ {
+ if (max_deg == x.max_deg)
+ return max_lcnops < x.max_lcnops;
+ else
+ return max_deg < x.max_deg;
+ }
};
// Vector of sym_desc structures
int deg_b = b.degree(*(it->sym));
it->deg_a = deg_a;
it->deg_b = deg_b;
- it->max_deg = std::max(deg_a,deg_b);
+ it->max_deg = std::max(deg_a, deg_b);
+ it->max_lcnops = std::max(a.lcoeff(*(it->sym)).nops(), b.lcoeff(*(it->sym)).nops());
it->ldeg_a = a.ldegree(*(it->sym));
it->ldeg_b = b.ldegree(*(it->sym));
it++;
std::clog << "Symbols:\n";
it = v.begin(); itend = v.end();
while (it != itend) {
- std::clog << " " << *it->sym << ": deg_a=" << it->deg_a << ", deg_b=" << it->deg_b << ", ldeg_a=" << it->ldeg_a << ", ldeg_b=" << it->ldeg_b << ", max_deg=" << it->max_deg << endl;
+ std::clog << " " << *it->sym << ": deg_a=" << it->deg_a << ", deg_b=" << it->deg_b << ", ldeg_a=" << it->ldeg_a << ", ldeg_b=" << it->ldeg_b << ", max_deg=" << it->max_deg << ", max_lcnops=" << it->max_lcnops << endl;
std::clog << " lcoeff_a=" << a.lcoeff(*(it->sym)) << ", lcoeff_b=" << b.lcoeff(*(it->sym)) << endl;
it++;
}
static numeric lcmcoeff(const ex &e, const numeric &l)
{
if (e.info(info_flags::rational))
- return lcm(ex_to_numeric(e).denom(), l);
+ return lcm(ex_to<numeric>(e).denom(), l);
else if (is_ex_exactly_of_type(e, add)) {
numeric c = _num1();
for (unsigned i=0; i<e.nops(); i++)
for (unsigned i=0; i<e.nops(); i++)
c *= lcmcoeff(e.op(i), _num1());
return lcm(c, l);
- } else if (is_ex_exactly_of_type(e, power))
- return pow(lcmcoeff(e.op(0), l), ex_to_numeric(e.op(1)));
+ } else if (is_ex_exactly_of_type(e, power)) {
+ if (is_ex_exactly_of_type(e.op(0), symbol))
+ return l;
+ else
+ return pow(lcmcoeff(e.op(0), l), ex_to<numeric>(e.op(1)));
+ }
return l;
}
static ex multiply_lcm(const ex &e, const numeric &lcm)
{
if (is_ex_exactly_of_type(e, mul)) {
- ex c = _ex1();
+ unsigned num = e.nops();
+ exvector v; v.reserve(num + 1);
numeric lcm_accum = _num1();
for (unsigned i=0; i<e.nops(); i++) {
numeric op_lcm = lcmcoeff(e.op(i), _num1());
- c *= multiply_lcm(e.op(i), op_lcm);
+ v.push_back(multiply_lcm(e.op(i), op_lcm));
lcm_accum *= op_lcm;
}
- c *= lcm / lcm_accum;
- return c;
+ v.push_back(lcm / lcm_accum);
+ return (new mul(v))->setflag(status_flags::dynallocated);
} else if (is_ex_exactly_of_type(e, add)) {
- ex c = _ex0();
- for (unsigned i=0; i<e.nops(); i++)
- c += multiply_lcm(e.op(i), lcm);
- return c;
+ unsigned num = e.nops();
+ exvector v; v.reserve(num);
+ for (unsigned i=0; i<num; i++)
+ v.push_back(multiply_lcm(e.op(i), lcm));
+ return (new add(v))->setflag(status_flags::dynallocated);
} else if (is_ex_exactly_of_type(e, power)) {
- return pow(multiply_lcm(e.op(0), lcm.power(ex_to_numeric(e.op(1)).inverse())), e.op(1));
+ if (is_ex_exactly_of_type(e.op(0), symbol))
+ return e * lcm;
+ else
+ return pow(multiply_lcm(e.op(0), lcm.power(ex_to<numeric>(e.op(1)).inverse())), e.op(1));
} else
return e * lcm;
}
while (it != itend) {
GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
GINAC_ASSERT(is_ex_exactly_of_type(it->coeff,numeric));
- c = gcd(ex_to_numeric(it->coeff), c);
+ c = gcd(ex_to<numeric>(it->coeff), c);
it++;
}
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
- c = gcd(ex_to_numeric(overall_coeff),c);
+ c = gcd(ex_to<numeric>(overall_coeff),c);
return c;
}
}
#endif // def DO_GINAC_ASSERT
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
- return abs(ex_to_numeric(overall_coeff));
+ return abs(ex_to<numeric>(overall_coeff));
}
throw(std::invalid_argument("quo: arguments must be polynomials over the rationals"));
// Polynomial long division
- ex q = _ex0();
ex r = a.expand();
if (r.is_zero())
return r;
int rdeg = r.degree(x);
ex blcoeff = b.expand().coeff(x, bdeg);
bool blcoeff_is_numeric = is_ex_exactly_of_type(blcoeff, numeric);
+ exvector v; v.reserve(rdeg - bdeg + 1);
while (rdeg >= bdeg) {
ex term, rcoeff = r.coeff(x, rdeg);
if (blcoeff_is_numeric)
term = rcoeff / blcoeff;
else {
if (!divide(rcoeff, blcoeff, term, false))
- return *new ex(fail());
+ return (new fail())->setflag(status_flags::dynallocated);
}
term *= power(x, rdeg - bdeg);
- q += term;
+ v.push_back(term);
r -= (term * b).expand();
if (r.is_zero())
break;
rdeg = r.degree(x);
}
- return q;
+ return (new add(v))->setflag(status_flags::dynallocated);
}
if (is_ex_exactly_of_type(b, numeric))
return _ex0();
else
- return b;
+ return a;
}
#if FAST_COMPARE
if (a.is_equal(b))
term = rcoeff / blcoeff;
else {
if (!divide(rcoeff, blcoeff, term, false))
- return *new ex(fail());
+ return (new fail())->setflag(status_flags::dynallocated);
}
term *= power(x, rdeg - bdeg);
r -= (term * b).expand();
}
+/** Decompose rational function a(x)=N(x)/D(x) into P(x)+n(x)/D(x)
+ * with degree(n, x) < degree(D, x).
+ *
+ * @param a rational function in x
+ * @param x a is a function of x
+ * @return decomposed function. */
+ex decomp_rational(const ex &a, const symbol &x)
+{
+ ex nd = numer_denom(a);
+ ex numer = nd.op(0), denom = nd.op(1);
+ ex q = quo(numer, denom, x);
+ if (is_ex_exactly_of_type(q, fail))
+ return a;
+ else
+ return q + rem(numer, denom, x) / denom;
+}
+
+
/** Pseudo-remainder of polynomials a(x) and b(x) in Z[x].
*
* @param a first polynomial in x (dividend)
* @param check_args check whether a and b are polynomials with rational
* coefficients (defaults to "true")
* @return sparse pseudo-remainder of a(x) and b(x) in Z[x] */
-
ex sprem(const ex &a, const ex &b, const symbol &x, bool check_args)
{
if (b.is_zero())
int rdeg = r.degree(*x);
ex blcoeff = b.expand().coeff(*x, bdeg);
bool blcoeff_is_numeric = is_ex_exactly_of_type(blcoeff, numeric);
+ exvector v; v.reserve(rdeg - bdeg + 1);
while (rdeg >= bdeg) {
ex term, rcoeff = r.coeff(*x, rdeg);
if (blcoeff_is_numeric)
if (!divide(rcoeff, blcoeff, term, false))
return false;
term *= power(*x, rdeg - bdeg);
- q += term;
+ v.push_back(term);
r -= (term * b).expand();
- if (r.is_zero())
+ if (r.is_zero()) {
+ q = (new add(v))->setflag(status_flags::dynallocated);
return true;
+ }
rdeg = r.degree(*x);
}
return false;
typedef std::pair<ex, bool> exbool;
struct ex2_less {
- bool operator() (const ex2 p, const ex2 q) const
+ bool operator() (const ex2 &p, const ex2 &q) const
{
- return p.first.compare(q.first) < 0 || (!(q.first.compare(p.first) < 0) && p.second.compare(q.second) < 0);
+ int cmp = p.first.compare(q.first);
+ return ((cmp<0) || (!(cmp>0) && p.second.compare(q.second)<0));
}
};
int rdeg = adeg;
ex eb = b.expand();
ex blcoeff = eb.coeff(*x, bdeg);
+ exvector v; v.reserve(rdeg - bdeg + 1);
while (rdeg >= bdeg) {
ex term, rcoeff = r.coeff(*x, rdeg);
if (!divide_in_z(rcoeff, blcoeff, term, var+1))
break;
term = (term * power(*x, rdeg - bdeg)).expand();
- q += term;
+ v.push_back(term);
r -= (term * eb).expand();
if (r.is_zero()) {
+ q = (new add(v))->setflag(status_flags::dynallocated);
#if USE_REMEMBER
dr_remember[ex2(a, b)] = exbool(q, true);
#endif
return bp->max_coefficient();
}
+/** Implementation ex::max_coefficient().
+ * @see heur_gcd */
numeric basic::max_coefficient(void) const
{
return _num1();
epvector::const_iterator it = seq.begin();
epvector::const_iterator itend = seq.end();
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
- numeric cur_max = abs(ex_to_numeric(overall_coeff));
+ numeric cur_max = abs(ex_to<numeric>(overall_coeff));
while (it != itend) {
numeric a;
GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
- a = abs(ex_to_numeric(it->coeff));
+ a = abs(ex_to<numeric>(it->coeff));
if (a > cur_max)
cur_max = a;
it++;
}
#endif // def DO_GINAC_ASSERT
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
- return abs(ex_to_numeric(overall_coeff));
+ return abs(ex_to<numeric>(overall_coeff));
}
ex numeric::smod(const numeric &xi) const
{
-#ifndef NO_NAMESPACE_GINAC
return GiNaC::smod(*this, xi);
-#else // ndef NO_NAMESPACE_GINAC
- return ::smod(*this, xi);
-#endif // ndef NO_NAMESPACE_GINAC
}
ex add::smod(const numeric &xi) const
epvector::const_iterator itend = seq.end();
while (it != itend) {
GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
-#ifndef NO_NAMESPACE_GINAC
- numeric coeff = GiNaC::smod(ex_to_numeric(it->coeff), xi);
-#else // ndef NO_NAMESPACE_GINAC
- numeric coeff = ::smod(ex_to_numeric(it->coeff), xi);
-#endif // ndef NO_NAMESPACE_GINAC
+ numeric coeff = GiNaC::smod(ex_to<numeric>(it->coeff), xi);
if (!coeff.is_zero())
newseq.push_back(expair(it->rest, coeff));
it++;
}
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-#ifndef NO_NAMESPACE_GINAC
- numeric coeff = GiNaC::smod(ex_to_numeric(overall_coeff), xi);
-#else // ndef NO_NAMESPACE_GINAC
- numeric coeff = ::smod(ex_to_numeric(overall_coeff), xi);
-#endif // ndef NO_NAMESPACE_GINAC
+ numeric coeff = GiNaC::smod(ex_to<numeric>(overall_coeff), xi);
return (new add(newseq,coeff))->setflag(status_flags::dynallocated);
}
it++;
}
#endif // def DO_GINAC_ASSERT
- mul * mulcopyp=new mul(*this);
+ mul * mulcopyp = new mul(*this);
GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-#ifndef NO_NAMESPACE_GINAC
- mulcopyp->overall_coeff = GiNaC::smod(ex_to_numeric(overall_coeff),xi);
-#else // ndef NO_NAMESPACE_GINAC
- mulcopyp->overall_coeff = ::smod(ex_to_numeric(overall_coeff),xi);
-#endif // ndef NO_NAMESPACE_GINAC
+ mulcopyp->overall_coeff = GiNaC::smod(ex_to<numeric>(overall_coeff),xi);
mulcopyp->clearflag(status_flags::evaluated);
mulcopyp->clearflag(status_flags::hash_calculated);
return mulcopyp->setflag(status_flags::dynallocated);
/** xi-adic polynomial interpolation */
-static ex interpolate(const ex &gamma, const numeric &xi, const symbol &x)
+static ex interpolate(const ex &gamma, const numeric &xi, const symbol &x, int degree_hint = 1)
{
- ex g = _ex0();
+ exvector g; g.reserve(degree_hint);
ex e = gamma;
numeric rxi = xi.inverse();
for (int i=0; !e.is_zero(); i++) {
ex gi = e.smod(xi);
- g += gi * power(x, i);
+ g.push_back(gi * power(x, i));
e = (e - gi) * rxi;
}
- return g;
+ return (new add(g))->setflag(status_flags::dynallocated);
}
/** Exception thrown by heur_gcd() to signal failure. */
heur_gcd_called++;
#endif
- // Algorithms only works for non-vanishing input polynomials
+ // Algorithm only works for non-vanishing input polynomials
if (a.is_zero() || b.is_zero())
- return *new ex(fail());
+ return (new fail())->setflag(status_flags::dynallocated);
// GCD of two numeric values -> CLN
if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric)) {
- numeric g = gcd(ex_to_numeric(a), ex_to_numeric(b));
+ numeric g = gcd(ex_to<numeric>(a), ex_to<numeric>(b));
if (ca)
- *ca = ex_to_numeric(a) / g;
+ *ca = ex_to<numeric>(a) / g;
if (cb)
- *cb = ex_to_numeric(b) / g;
+ *cb = ex_to<numeric>(b) / g;
return g;
}
numeric rgc = gc.inverse();
ex p = a * rgc;
ex q = b * rgc;
- int maxdeg = std::max(p.degree(x),q.degree(x));
+ int maxdeg = std::max(p.degree(x), q.degree(x));
// Find evaluation point
numeric mp = p.max_coefficient();
// 6 tries maximum
for (int t=0; t<6; t++) {
if (xi.int_length() * maxdeg > 100000) {
-//std::clog << "giving up heur_gcd, xi.int_length = " << xi.int_length() << ", maxdeg = " << maxdeg << endl;
+//std::clog << "giving up heur_gcd, xi.int_length = " << xi.int_length() << ", maxdeg = " << maxdeg << std::endl;
throw gcdheu_failed();
}
if (!is_ex_exactly_of_type(gamma, fail)) {
// Reconstruct polynomial from GCD of mapped polynomials
- ex g = interpolate(gamma, xi, x);
+ ex g = interpolate(gamma, xi, x, maxdeg);
// Remove integer content
g /= g.integer_content();
if (divide_in_z(p, g, ca ? *ca : dummy, var) && divide_in_z(q, g, cb ? *cb : dummy, var)) {
g *= gc;
ex lc = g.lcoeff(x);
- if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+ if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
return -g;
else
return g;
if (ca)
*ca = cp;
ex lc = g.lcoeff(x);
- if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+ if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
return -g;
else
return g;
if (cb)
*cb = cq;
ex lc = g.lcoeff(x);
- if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+ if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
return -g;
else
return g;
// Next evaluation point
xi = iquo(xi * isqrt(isqrt(xi)) * numeric(73794), numeric(27011));
}
- return *new ex(fail());
+ return (new fail())->setflag(status_flags::dynallocated);
}
// GCD of numerics -> CLN
if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric)) {
- numeric g = gcd(ex_to_numeric(a), ex_to_numeric(b));
+ numeric g = gcd(ex_to<numeric>(a), ex_to<numeric>(b));
if (ca || cb) {
if (g.is_zero()) {
if (ca)
*cb = _ex0();
} else {
if (ca)
- *ca = ex_to_numeric(a) / g;
+ *ca = ex_to<numeric>(a) / g;
if (cb)
- *cb = ex_to_numeric(b) / g;
+ *cb = ex_to<numeric>(b) / g;
}
}
return g;
if (is_ex_exactly_of_type(b, mul) && b.nops() > a.nops())
goto factored_b;
factored_a:
- ex g = _ex1();
- ex acc_ca = _ex1();
+ unsigned num = a.nops();
+ exvector g; g.reserve(num);
+ exvector acc_ca; acc_ca.reserve(num);
ex part_b = b;
- for (unsigned i=0; i<a.nops(); i++) {
+ for (unsigned i=0; i<num; i++) {
ex part_ca, part_cb;
- g *= gcd(a.op(i), part_b, &part_ca, &part_cb, check_args);
- acc_ca *= part_ca;
+ g.push_back(gcd(a.op(i), part_b, &part_ca, &part_cb, check_args));
+ acc_ca.push_back(part_ca);
part_b = part_cb;
}
if (ca)
- *ca = acc_ca;
+ *ca = (new mul(acc_ca))->setflag(status_flags::dynallocated);
if (cb)
*cb = part_b;
- return g;
+ return (new mul(g))->setflag(status_flags::dynallocated);
} else if (is_ex_exactly_of_type(b, mul)) {
if (is_ex_exactly_of_type(a, mul) && a.nops() > b.nops())
goto factored_a;
factored_b:
- ex g = _ex1();
- ex acc_cb = _ex1();
+ unsigned num = b.nops();
+ exvector g; g.reserve(num);
+ exvector acc_cb; acc_cb.reserve(num);
ex part_a = a;
- for (unsigned i=0; i<b.nops(); i++) {
+ for (unsigned i=0; i<num; i++) {
ex part_ca, part_cb;
- g *= gcd(part_a, b.op(i), &part_ca, &part_cb, check_args);
- acc_cb *= part_cb;
+ g.push_back(gcd(part_a, b.op(i), &part_ca, &part_cb, check_args));
+ acc_cb.push_back(part_cb);
part_a = part_ca;
}
if (ca)
*ca = part_a;
if (cb)
- *cb = acc_cb;
- return g;
+ *cb = (new mul(acc_cb))->setflag(status_flags::dynallocated);
+ return (new mul(g))->setflag(status_flags::dynallocated);
}
#if FAST_COMPARE
int min_ldeg = std::min(ldeg_a,ldeg_b);
if (min_ldeg > 0) {
ex common = power(x, min_ldeg);
-//std::clog << "trivial common factor " << common << endl;
+//std::clog << "trivial common factor " << common << std::endl;
return gcd((aex / common).expand(), (bex / common).expand(), ca, cb, false) * common;
}
// Try to eliminate variables
if (var->deg_a == 0) {
-//std::clog << "eliminating variable " << x << " from b" << endl;
+//std::clog << "eliminating variable " << x << " from b" << std::endl;
ex c = bex.content(x);
ex g = gcd(aex, c, ca, cb, false);
if (cb)
*cb *= bex.unit(x) * bex.primpart(x, c);
return g;
} else if (var->deg_b == 0) {
-//std::clog << "eliminating variable " << x << " from a" << endl;
+//std::clog << "eliminating variable " << x << " from a" << std::endl;
ex c = aex.content(x);
ex g = gcd(c, bex, ca, cb, false);
if (ca)
try {
g = heur_gcd(aex, bex, ca, cb, var);
} catch (gcdheu_failed) {
- g = *new ex(fail());
+ g = fail();
}
if (is_ex_exactly_of_type(g, fail)) {
-//std::clog << "heuristics failed" << endl;
+//std::clog << "heuristics failed" << std::endl;
#if STATISTICS
heur_gcd_failed++;
#endif
ex lcm(const ex &a, const ex &b, bool check_args)
{
if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric))
- return lcm(ex_to_numeric(a), ex_to_numeric(b));
+ return lcm(ex_to<numeric>(a), ex_to<numeric>(b));
if (check_args && (!a.info(info_flags::rational_polynomial) || !b.info(info_flags::rational_polynomial)))
throw(std::invalid_argument("lcm: arguments must be polynomials over the rationals"));
* Square-free factorization
*/
-// Univariate GCD of polynomials in Q[x] (used internally by sqrfree()).
-// a and b can be multivariate polynomials but they are treated as univariate polynomials in x.
-static ex univariate_gcd(const ex &a, const ex &b, const symbol &x)
+/** Compute square-free factorization of multivariate polynomial a(x) using
+ * Yun´s algorithm. Used internally by sqrfree().
+ *
+ * @param a multivariate polynomial over Z[X], treated here as univariate
+ * polynomial in x.
+ * @param x variable to factor in
+ * @return vector of factors sorted in ascending degree */
+static exvector sqrfree_yun(const ex &a, const symbol &x)
{
- if (a.is_zero())
- return b;
- if (b.is_zero())
- return a;
- if (a.is_equal(_ex1()) || b.is_equal(_ex1()))
- return _ex1();
- if (is_ex_of_type(a, numeric) && is_ex_of_type(b, numeric))
- return gcd(ex_to_numeric(a), ex_to_numeric(b));
- if (!a.info(info_flags::rational_polynomial) || !b.info(info_flags::rational_polynomial))
- throw(std::invalid_argument("univariate_gcd: arguments must be polynomials over the rationals"));
+ exvector res;
+ ex w = a;
+ ex z = w.diff(x);
+ ex g = gcd(w, z);
+ if (g.is_equal(_ex1())) {
+ res.push_back(a);
+ return res;
+ }
+ ex y;
+ do {
+ w = quo(w, g, x);
+ y = quo(z, g, x);
+ z = y - w.diff(x);
+ g = gcd(w, z);
+ res.push_back(g);
+ } while (!z.is_zero());
+ return res;
+}
- // Euclidean algorithm
- ex c, d, r;
- if (a.degree(x) >= b.degree(x)) {
- c = a;
- d = b;
+/** Compute square-free factorization of multivariate polynomial in Q[X].
+ *
+ * @param a multivariate polynomial over Q[X]
+ * @param x lst of variables to factor in, may be left empty for autodetection
+ * @return polynomail a in square-free factored form. */
+ex sqrfree(const ex &a, const lst &l)
+{
+ if (is_ex_of_type(a,numeric) || // algorithm does not trap a==0
+ is_ex_of_type(a,symbol)) // shortcut
+ return a;
+ // If no lst of variables to factorize in was specified we have to
+ // invent one now. Maybe one can optimize here by reversing the order
+ // or so, I don't know.
+ lst args;
+ if (l.nops()==0) {
+ sym_desc_vec sdv;
+ get_symbol_stats(a, _ex0(), sdv);
+ for (sym_desc_vec::iterator it=sdv.begin(); it!=sdv.end(); ++it)
+ args.append(*it->sym);
} else {
- c = b;
- d = a;
- }
- for (;;) {
- r = rem(c, d, x, false);
- if (r.is_zero())
- break;
- c = d;
- d = r;
- }
- return d / d.lcoeff(x);
+ args = l;
+ }
+ // Find the symbol to factor in at this stage
+ if (!is_ex_of_type(args.op(0), symbol))
+ throw (std::runtime_error("sqrfree(): invalid factorization variable"));
+ const symbol x = ex_to<symbol>(args.op(0));
+ // convert the argument from something in Q[X] to something in Z[X]
+ numeric lcm = lcm_of_coefficients_denominators(a);
+ ex tmp = multiply_lcm(a,lcm);
+ // find the factors
+ exvector factors = sqrfree_yun(tmp,x);
+ // construct the next list of symbols with the first element popped
+ lst newargs;
+ for (int i=1; i<args.nops(); ++i)
+ newargs.append(args.op(i));
+ // recurse down the factors in remaining vars
+ if (newargs.nops()>0) {
+ for (exvector::iterator i=factors.begin(); i!=factors.end(); ++i)
+ *i = sqrfree(*i, newargs);
+ }
+ // Done with recursion, now construct the final result
+ ex result = _ex1();
+ exvector::iterator it = factors.begin();
+ for (int p = 1; it!=factors.end(); ++it, ++p)
+ result *= power(*it, p);
+ // Yun's algorithm does not account for constant factors. (For
+ // univariate polynomials it works only in the monic case.) We can
+ // correct this by inserting what has been lost back into the result:
+ result = result * quo(tmp, result, x);
+ return result * lcm.inverse();
}
-
-/** Compute square-free factorization of multivariate polynomial a(x) using
- * Yun´s algorithm.
+/** Compute square-free partial fraction decomposition of rational function
+ * a(x).
*
- * @param a multivariate polynomial
- * @param x variable to factor in
- * @return factored polynomial */
-ex sqrfree(const ex &a, const symbol &x)
-{
- int i = 1;
- ex res = _ex1();
- ex b = a.diff(x);
- ex c = univariate_gcd(a, b, x);
- ex w;
- if (c.is_equal(_ex1())) {
- w = a;
- } else {
- w = quo(a, c, x);
- ex y = quo(b, c, x);
- ex z = y - w.diff(x);
- while (!z.is_zero()) {
- ex g = univariate_gcd(w, z, x);
- res *= power(g, i);
- w = quo(w, g, x);
- y = quo(z, g, x);
- z = y - w.diff(x);
- i++;
+ * @param a rational function over Z[x], treated as univariate polynomial
+ * in x
+ * @param x variable to factor in
+ * @return decomposed rational function */
+ex sqrfree_parfrac(const ex & a, const symbol & x)
+{
+ // Find numerator and denominator
+ ex nd = numer_denom(a);
+ ex numer = nd.op(0), denom = nd.op(1);
+//clog << "numer = " << numer << ", denom = " << denom << endl;
+
+ // Convert N(x)/D(x) -> Q(x) + R(x)/D(x), so degree(R) < degree(D)
+ ex red_poly = quo(numer, denom, x), red_numer = rem(numer, denom, x).expand();
+//clog << "red_poly = " << red_poly << ", red_numer = " << red_numer << endl;
+
+ // Factorize denominator and compute cofactors
+ exvector yun = sqrfree_yun(denom, x);
+//clog << "yun factors: " << exprseq(yun) << endl;
+ int num_yun = yun.size();
+ exvector factor; factor.reserve(num_yun);
+ exvector cofac; cofac.reserve(num_yun);
+ for (unsigned i=0; i<num_yun; i++) {
+ if (!yun[i].is_equal(_ex1())) {
+ for (unsigned j=0; j<=i; j++) {
+ factor.push_back(pow(yun[i], j+1));
+ ex prod = _ex1();
+ for (unsigned k=0; k<num_yun; k++) {
+ if (k == i)
+ prod *= pow(yun[k], i-j);
+ else
+ prod *= pow(yun[k], k+1);
+ }
+ cofac.push_back(prod.expand());
+ }
}
}
- return res * power(w, i);
+ int num_factors = factor.size();
+//clog << "factors : " << exprseq(factor) << endl;
+//clog << "cofactors: " << exprseq(cofac) << endl;
+
+ // Construct coefficient matrix for decomposition
+ int max_denom_deg = denom.degree(x);
+ matrix sys(max_denom_deg + 1, num_factors);
+ matrix rhs(max_denom_deg + 1, 1);
+ for (unsigned i=0; i<=max_denom_deg; i++) {
+ for (unsigned j=0; j<num_factors; j++)
+ sys(i, j) = cofac[j].coeff(x, i);
+ rhs(i, 0) = red_numer.coeff(x, i);
+ }
+//clog << "coeffs: " << sys << endl;
+//clog << "rhs : " << rhs << endl;
+
+ // Solve resulting linear system
+ matrix vars(num_factors, 1);
+ for (unsigned i=0; i<num_factors; i++)
+ vars(i, 0) = symbol();
+ matrix sol = sys.solve(vars, rhs);
+
+ // Sum up decomposed fractions
+ ex sum = 0;
+ for (unsigned i=0; i<num_factors; i++)
+ sum += sol(i, 0) / factor[i];
+
+ return red_poly + sum;
}
* the information that (a+b) is the numerator and 3 is the denominator.
*/
+
/** Create a symbol for replacing the expression "e" (or return a previously
* assigned symbol). The symbol is appended to sym_lst and returned, the
* expression is appended to repl_lst.
return es;
}
-/** Default implementation of ex::normal(). It replaces the object with a
- * temporary symbol.
+
+/** Function object to be applied by basic::normal(). */
+struct normal_map_function : public map_function {
+ int level;
+ normal_map_function(int l) : level(l) {}
+ ex operator()(const ex & e) { return normal(e, level); }
+};
+
+/** Default implementation of ex::normal(). It normalizes the children and
+ * replaces the object with a temporary symbol.
* @see ex::normal */
ex basic::normal(lst &sym_lst, lst &repl_lst, int level) const
{
- return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+ if (nops() == 0)
+ return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+ else {
+ if (level == 1)
+ return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+ else if (level == -max_recursion_level)
+ throw(std::runtime_error("max recursion level reached"));
+ else {
+ normal_map_function map_normal(level - 1);
+ return (new lst(replace_with_symbol(map(map_normal), sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+ }
+ }
}
ex den = d;
numeric pre_factor = _num1();
-//std::clog << "frac_cancel num = " << num << ", den = " << den << endl;
+//std::clog << "frac_cancel num = " << num << ", den = " << den << std::endl;
// Handle trivial case where denominator is 1
if (den.is_equal(_ex1()))
const symbol *x;
if (get_first_symbol(den, x)) {
GINAC_ASSERT(is_ex_exactly_of_type(den.unit(*x),numeric));
- if (ex_to_numeric(den.unit(*x)).is_negative()) {
+ if (ex_to<numeric>(den.unit(*x)).is_negative()) {
num *= _ex_1();
den *= _ex_1();
}
}
// Return result as list
-//std::clog << " returns num = " << num << ", den = " << den << ", pre_factor = " << pre_factor << endl;
+//std::clog << " returns num = " << num << ", den = " << den << ", pre_factor = " << pre_factor << std::endl;
return (new lst(num * pre_factor.numer(), den * pre_factor.denom()))->setflag(status_flags::dynallocated);
}
// Add fractions sequentially
exvector::const_iterator num_it = nums.begin(), num_itend = nums.end();
exvector::const_iterator den_it = dens.begin(), den_itend = dens.end();
-//std::clog << " num = " << *num_it << ", den = " << *den_it << endl;
+//std::clog << " num = " << *num_it << ", den = " << *den_it << std::endl;
ex num = *num_it++, den = *den_it++;
while (num_it != num_itend) {
-//std::clog << " num = " << *num_it << ", den = " << *den_it << endl;
+//std::clog << " num = " << *num_it << ", den = " << *den_it << std::endl;
ex next_num = *num_it++, next_den = *den_it++;
// Trivially add sequences of fractions with identical denominators
num = ((num * co_den2) + (next_num * co_den1)).expand();
den *= co_den2; // this is the lcm(den, next_den)
}
-//std::clog << " common denominator = " << den << endl;
+//std::clog << " common denominator = " << den << std::endl;
// Cancel common factors from num/den
return frac_cancel(num, den);
throw(std::runtime_error("max recursion level reached"));
// Normalize children, separate into numerator and denominator
- ex num = _ex1();
- ex den = _ex1();
+ exvector num; num.reserve(seq.size());
+ exvector den; den.reserve(seq.size());
ex n;
epvector::const_iterator it = seq.begin(), itend = seq.end();
while (it != itend) {
n = recombine_pair_to_ex(*it).bp->normal(sym_lst, repl_lst, level-1);
- num *= n.op(0);
- den *= n.op(1);
+ num.push_back(n.op(0));
+ den.push_back(n.op(1));
it++;
}
n = overall_coeff.bp->normal(sym_lst, repl_lst, level-1);
- num *= n.op(0);
- den *= n.op(1);
+ num.push_back(n.op(0));
+ den.push_back(n.op(1));
// Perform fraction cancellation
- return frac_cancel(num, den);
+ return frac_cancel((new mul(num))->setflag(status_flags::dynallocated),
+ (new mul(den))->setflag(status_flags::dynallocated));
}
}
-/** Implementation of ex::normal() for pseries. It normalizes each coefficient and
- * replaces the series by a temporary symbol.
+/** Implementation of ex::normal() for pseries. It normalizes each coefficient
+ * and replaces the series by a temporary symbol.
* @see ex::normal */
ex pseries::normal(lst &sym_lst, lst &repl_lst, int level) const
{
- epvector new_seq;
- new_seq.reserve(seq.size());
-
- epvector::const_iterator it = seq.begin(), itend = seq.end();
- while (it != itend) {
- new_seq.push_back(expair(it->rest.normal(), it->coeff));
- it++;
+ epvector newseq;
+ for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
+ ex restexp = i->rest.normal();
+ if (!restexp.is_zero())
+ newseq.push_back(expair(restexp, i->coeff));
}
- ex n = pseries(relational(var,point), new_seq);
+ ex n = pseries(relational(var,point), newseq);
return (new lst(replace_with_symbol(n, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
}
-/** Implementation of ex::normal() for relationals. It normalizes both sides.
- * @see ex::normal */
-ex relational::normal(lst &sym_lst, lst &repl_lst, int level) const
-{
- return (new lst(relational(lh.normal(), rh.normal(), o), _ex1()))->setflag(status_flags::dynallocated);
-}
-
-
/** Normalization of rational functions.
* This function converts an expression to its normal form
* "numerator/denominator", where numerator and denominator are (relatively
return e.op(0) / e.op(1);
}
-/** Numerator of an expression. If the expression is not of the normal form
- * "numerator/denominator", it is first converted to this form and then the
- * numerator is returned.
+/** Get numerator of an expression. If the expression is not of the normal
+ * form "numerator/denominator", it is first converted to this form and
+ * then the numerator is returned.
*
* @see ex::normal
* @return numerator */
return e.op(0);
}
-/** Denominator of an expression. If the expression is not of the normal form
- * "numerator/denominator", it is first converted to this form and then the
- * denominator is returned.
+/** Get denominator of an expression. If the expression is not of the normal
+ * form "numerator/denominator", it is first converted to this form and
+ * then the denominator is returned.
*
* @see ex::normal
* @return denominator */
return e.op(1);
}
+/** Get numerator and denominator of an expression. If the expresison is not
+ * of the normal form "numerator/denominator", it is first converted to this
+ * form and then a list [numerator, denominator] is returned.
+ *
+ * @see ex::normal
+ * @return a list [numerator, denominator] */
+ex ex::numer_denom(void) const
+{
+ lst sym_lst, repl_lst;
+
+ ex e = bp->normal(sym_lst, repl_lst, 0);
+ GINAC_ASSERT(is_ex_of_type(e, lst));
+
+ // Re-insert replaced symbols
+ if (sym_lst.nops() > 0)
+ return e.subs(sym_lst, repl_lst);
+ else
+ return e;
+}
+
/** Default implementation of ex::to_rational(). It replaces the object with a
* temporary symbol.
}
-#ifndef NO_NAMESPACE_GINAC
} // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC