* Implementation of GiNaC's products of expressions. */
/*
- * GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2002 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
while (it != itend) {
// If the first argument is a negative integer power, it gets printed as "1.0/<expr>"
- if (it == seq.begin() && ex_to<numeric>(it->coeff).is_integer() && it->coeff.compare(_num0) < 0) {
- if (is_a<print_csrc_cl_N>(c))
+ bool needclosingparenthesis = false;
+ if (it == seq.begin() && it->coeff.info(info_flags::negint)) {
+ if (is_a<print_csrc_cl_N>(c)) {
c.s << "recip(";
- else
+ needclosingparenthesis = true;
+ } else
c.s << "1.0/";
}
// If the exponent is 1 or -1, it is left out
- if (it->coeff.compare(_ex1) == 0 || it->coeff.compare(_num_1) == 0)
+ if (it->coeff.is_equal(_ex1) || it->coeff.is_equal(_ex_1))
it->rest.print(c, precedence());
- else {
+ else if (it->coeff.info(info_flags::negint))
// Outer parens around ex needed for broken gcc-2.95 parser:
- (ex(power(it->rest, abs(ex_to<numeric>(it->coeff))))).print(c, level);
- }
+ (ex(power(it->rest, -ex_to<numeric>(it->coeff)))).print(c, level);
+ else
+ // Outer parens around ex needed for broken gcc-2.95 parser:
+ (ex(power(it->rest, ex_to<numeric>(it->coeff)))).print(c, level);
+
+ if (needclosingparenthesis)
+ c.s << ")";
// Separator is "/" for negative integer powers, "*" otherwise
++it;
if (it != itend) {
- if (ex_to<numeric>(it->coeff).is_integer() && it->coeff.compare(_num0) < 0)
+ if (it->coeff.info(info_flags::negint))
c.s << "/";
else
c.s << "*";
c.s << "(";
}
- bool first = true;
-
// First print the overall numeric coefficient
numeric coeff = ex_to<numeric>(overall_coeff);
if (coeff.csgn() == -1)
// Then proceed with the remaining factors
epvector::const_iterator it = seq.begin(), itend = seq.end();
- while (it != itend) {
- if (!first) {
- if (is_a<print_latex>(c))
- c.s << ' ';
+ if (is_a<print_latex>(c)) {
+
+ // Separate factors into those with negative numeric exponent
+ // and all others
+ exvector neg_powers, others;
+ while (it != itend) {
+ GINAC_ASSERT(is_a<numeric>(it->coeff));
+ if (ex_to<numeric>(it->coeff).is_negative())
+ neg_powers.push_back(recombine_pair_to_ex(expair(it->rest, -(it->coeff))));
else
- c.s << '*';
+ others.push_back(recombine_pair_to_ex(*it));
+ ++it;
+ }
+
+ if (!neg_powers.empty()) {
+
+ // Factors with negative exponent are printed as a fraction
+ c.s << "\\frac{";
+ mul(others).eval().print(c);
+ c.s << "}{";
+ mul(neg_powers).eval().print(c);
+ c.s << "}";
+
} else {
- first = false;
+
+ // All other factors are printed in the ordinary way
+ exvector::const_iterator vit = others.begin(), vitend = others.end();
+ while (vit != vitend) {
+ c.s << ' ';
+ vit->print(c, precedence());
+ ++vit;
+ }
+ }
+
+ } else {
+
+ bool first = true;
+ while (it != itend) {
+ if (!first)
+ c.s << '*';
+ else
+ first = false;
+ recombine_pair_to_ex(*it).print(c, precedence());
+ ++it;
}
- recombine_pair_to_ex(*it).print(c, precedence());
- ++it;
}
if (precedence() <= level) {
(cit->coeff.is_equal(_ex1))) {
++number_of_adds;
if (is_ex_exactly_of_type(last_expanded, add)) {
+#if 0
+ // Expand a product of two sums, simple and robust version.
const add & add1 = ex_to<add>(last_expanded);
const add & add2 = ex_to<add>(cit->rest);
- int n1 = add1.nops();
- int n2 = add2.nops();
+ const int n1 = add1.nops();
+ const int n2 = add2.nops();
+ ex tmp_accu;
exvector distrseq;
- distrseq.reserve(n1*n2);
+ distrseq.reserve(n2);
for (int i1=0; i1<n1; ++i1) {
- for (int i2=0; i2<n2; ++i2) {
- distrseq.push_back(add1.op(i1) * add2.op(i2));
+ distrseq.clear();
+ // cache the first operand (for efficiency):
+ const ex op1 = add1.op(i1);
+ for (int i2=0; i2<n2; ++i2)
+ distrseq.push_back(op1 * add2.op(i2));
+ tmp_accu += (new add(distrseq))->
+ setflag(status_flags::dynallocated);
+ }
+ last_expanded = tmp_accu;
+#else
+ // Expand a product of two sums, aggressive version.
+ // Caring for the overall coefficients in separate loops can
+ // sometimes give a performance gain of up to 15%!
+
+ const int sizedifference = ex_to<add>(last_expanded).seq.size()-ex_to<add>(cit->rest).seq.size();
+ // add2 is for the inner loop and should be the bigger of the two sums
+ // in the presence of asymptotically good sorting:
+ const add& add1 = (sizedifference<0 ? ex_to<add>(last_expanded) : ex_to<add>(cit->rest));
+ const add& add2 = (sizedifference<0 ? ex_to<add>(cit->rest) : ex_to<add>(last_expanded));
+ const epvector::const_iterator add1begin = add1.seq.begin();
+ const epvector::const_iterator add1end = add1.seq.end();
+ const epvector::const_iterator add2begin = add2.seq.begin();
+ const epvector::const_iterator add2end = add2.seq.end();
+ epvector distrseq;
+ distrseq.reserve(add1.seq.size()+add2.seq.size());
+ // Multiply add2 with the overall coefficient of add1 and append it to distrseq:
+ if (!add1.overall_coeff.is_zero()) {
+ if (add1.overall_coeff.is_equal(_ex1))
+ distrseq.insert(distrseq.end(),add2begin,add2end);
+ else
+ for (epvector::const_iterator i=add2begin; i!=add2end; ++i)
+ distrseq.push_back(expair(i->rest, ex_to<numeric>(i->coeff).mul_dyn(ex_to<numeric>(add1.overall_coeff))));
+ }
+ // Multiply add1 with the overall coefficient of add2 and append it to distrseq:
+ if (!add2.overall_coeff.is_zero()) {
+ if (add2.overall_coeff.is_equal(_ex1))
+ distrseq.insert(distrseq.end(),add1begin,add1end);
+ else
+ for (epvector::const_iterator i=add1begin; i!=add1end; ++i)
+ distrseq.push_back(expair(i->rest, ex_to<numeric>(i->coeff).mul_dyn(ex_to<numeric>(add2.overall_coeff))));
+ }
+ // Compute the new overall coefficient and put it together:
+ ex tmp_accu = (new add(distrseq, add1.overall_coeff*add2.overall_coeff))->setflag(status_flags::dynallocated);
+ // Multiply explicitly all non-numeric terms of add1 and add2:
+ for (epvector::const_iterator i1=add1begin; i1!=add1end; ++i1) {
+ // We really have to combine terms here in order to compactify
+ // the result. Otherwise it would become waayy tooo bigg.
+ numeric oc;
+ distrseq.clear();
+ for (epvector::const_iterator i2=add2begin; i2!=add2end; ++i2) {
+ // Don't push_back expairs which might have a rest that evaluates to a numeric,
+ // since that would violate an invariant of expairseq:
+ const ex rest = (new mul(i1->rest, i2->rest))->setflag(status_flags::dynallocated);
+ if (is_ex_exactly_of_type(rest, numeric))
+ oc += ex_to<numeric>(rest).mul(ex_to<numeric>(i1->coeff).mul(ex_to<numeric>(i2->coeff)));
+ else
+ distrseq.push_back(expair(rest, ex_to<numeric>(i1->coeff).mul_dyn(ex_to<numeric>(i2->coeff))));
}
+ tmp_accu += (new add(distrseq, oc))->setflag(status_flags::dynallocated);
}
- last_expanded = (new add(distrseq))->
- setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));
+ last_expanded = tmp_accu;
+#endif
} else {
non_adds.push_back(split_ex_to_pair(last_expanded));
last_expanded = cit->rest;