* Implementation of GiNaC's products of expressions. */
/*
- * GiNaC Copyright (C) 1999-2006 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2007 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
#include "lst.h"
#include "archive.h"
#include "utils.h"
+#include "compiler.h"
namespace GiNaC {
epvector::const_iterator i = seq.begin(), end = seq.end();
while (i != end) {
if (ex_to<numeric>(i->coeff).is_integer())
- deg_sum += i->rest.degree(s) * ex_to<numeric>(i->coeff).to_int();
+ deg_sum += recombine_pair_to_ex(*i).degree(s);
+ else {
+ if (i->rest.has(s))
+ throw std::runtime_error("mul::degree() undefined degree because of non-integer exponent");
+ }
++i;
}
return deg_sum;
epvector::const_iterator i = seq.begin(), end = seq.end();
while (i != end) {
if (ex_to<numeric>(i->coeff).is_integer())
- deg_sum += i->rest.ldegree(s) * ex_to<numeric>(i->coeff).to_int();
+ deg_sum += recombine_pair_to_ex(*i).ldegree(s);
+ else {
+ if (i->rest.has(s))
+ throw std::runtime_error("mul::ldegree() undefined degree because of non-integer exponent");
+ }
++i;
}
return deg_sum;
return *this;
}
- int seq_size = seq.size();
+ size_t seq_size = seq.size();
if (overall_coeff.is_zero()) {
// *(...,x;0) -> 0
return _ex0;
}
return (new add(distrseq,
ex_to<numeric>(addref.overall_coeff).
- mul_dyn(ex_to<numeric>(overall_coeff))))
- ->setflag(status_flags::dynallocated | status_flags::evaluated);
+ mul_dyn(ex_to<numeric>(overall_coeff)))
+ )->setflag(status_flags::dynallocated | status_flags::evaluated);
+ } else if ((seq_size >= 2) && (! (flags & status_flags::expanded))) {
+ // Strip the content and the unit part from each term. Thus
+ // things like (-x+a)*(3*x-3*a) automagically turn into - 3*(x-a)2
+
+ epvector::const_iterator last = seq.end();
+ epvector::const_iterator i = seq.begin();
+ epvector::const_iterator j = seq.begin();
+ std::auto_ptr<epvector> s(new epvector);
+ numeric oc = *_num1_p;
+ bool something_changed = false;
+ while (i!=last) {
+ if (likely(! (is_a<add>(i->rest) && i->coeff.is_equal(_ex1)))) {
+ // power::eval has such a rule, no need to handle powers here
+ ++i;
+ continue;
+ }
+
+ // XXX: What is the best way to check if the polynomial is a primitive?
+ numeric c = i->rest.integer_content();
+ const numeric& lead_coeff =
+ ex_to<numeric>(ex_to<add>(i->rest).seq.begin()->coeff).div_dyn(c);
+ const bool canonicalizable = lead_coeff.is_integer();
+
+ // XXX: The main variable is chosen in a random way, so this code
+ // does NOT transform the term into the canonical form (thus, in some
+ // very unlucky event it can even loop forever). Hopefully the main
+ // variable will be the same for all terms in *this
+ const bool unit_normal = lead_coeff.is_pos_integer();
+ if (likely((c == *_num1_p) && ((! canonicalizable) || unit_normal))) {
+ ++i;
+ continue;
+ }
+
+ if (! something_changed) {
+ s->reserve(seq_size);
+ something_changed = true;
+ }
+
+ while ((j!=i) && (j!=last)) {
+ s->push_back(*j);
+ ++j;
+ }
+
+ if (! unit_normal)
+ c = c.mul(*_num_1_p);
+
+ oc = oc.mul(c);
+
+ // divide add by the number in place to save at least 2 .eval() calls
+ const add& addref = ex_to<add>(i->rest);
+ add* primitive = new add(addref);
+ primitive->setflag(status_flags::dynallocated);
+ primitive->clearflag(status_flags::hash_calculated);
+ primitive->overall_coeff = ex_to<numeric>(primitive->overall_coeff).div_dyn(c);
+ for (epvector::iterator ai = primitive->seq.begin();
+ ai != primitive->seq.end(); ++ai)
+ ai->coeff = ex_to<numeric>(ai->coeff).div_dyn(c);
+
+ s->push_back(expair(*primitive, _ex1));
+
+ ++i;
+ ++j;
+ }
+ if (something_changed) {
+ while (j!=last) {
+ s->push_back(*j);
+ ++j;
+ }
+ return (new mul(s, ex_to<numeric>(overall_coeff).mul_dyn(oc))
+ )->setflag(status_flags::dynallocated);
+ }
}
+
return this->hold();
}