X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=blobdiff_plain;f=ginac%2Fmul.cpp;h=bc80ef6eace60710c50771aeaacec263c48700c6;hb=d7c5ca75b0fc9e58a8676681e3801869e47ad911;hp=351a72cbcfaa20210b9b8097b91bca5f2a5541b6;hpb=d4df6322c4790ea932280602fdb584486f6101b6;p=ginac.git diff --git a/ginac/mul.cpp b/ginac/mul.cpp index 351a72cb..bc80ef6e 100644 --- a/ginac/mul.cpp +++ b/ginac/mul.cpp @@ -3,7 +3,7 @@ * 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 @@ -34,6 +34,8 @@ #include "lst.h" #include "archive.h" #include "utils.h" +#include "symbol.h" +#include "compiler.h" namespace GiNaC { @@ -315,7 +317,11 @@ int mul::degree(const ex & s) const epvector::const_iterator i = seq.begin(), end = seq.end(); while (i != end) { if (ex_to(i->coeff).is_integer()) - deg_sum += i->rest.degree(s) * ex_to(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; @@ -328,7 +334,11 @@ int mul::ldegree(const ex & s) const epvector::const_iterator i = seq.begin(), end = seq.end(); while (i != end) { if (ex_to(i->coeff).is_integer()) - deg_sum += i->rest.ldegree(s) * ex_to(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; @@ -414,7 +424,7 @@ ex mul::eval(int level) const return *this; } - int seq_size = seq.size(); + size_t seq_size = seq.size(); if (overall_coeff.is_zero()) { // *(...,x;0) -> 0 return _ex0; @@ -438,9 +448,81 @@ ex mul::eval(int level) const } return (new add(distrseq, ex_to(addref.overall_coeff). - mul_dyn(ex_to(overall_coeff)))) - ->setflag(status_flags::dynallocated | status_flags::evaluated); + mul_dyn(ex_to(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 s(new epvector); + numeric oc = *_num1_p; + bool something_changed = false; + while (i!=last) { + if (likely(! (is_a(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(ex_to(i->rest).seq.begin()->coeff).div(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(i->rest); + add* primitive = new add(addref); + primitive->setflag(status_flags::dynallocated); + primitive->clearflag(status_flags::hash_calculated); + primitive->overall_coeff = ex_to(primitive->overall_coeff).div_dyn(c); + for (epvector::iterator ai = primitive->seq.begin(); + ai != primitive->seq.end(); ++ai) + ai->coeff = ex_to(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(overall_coeff).mul_dyn(oc)) + )->setflag(status_flags::dynallocated); + } } + return this->hold(); } @@ -911,6 +993,24 @@ bool mul::can_be_further_expanded(const ex & e) ex mul::expand(unsigned options) const { + { + // trivial case: expanding the monomial (~ 30% of all calls) + epvector::const_iterator i = seq.begin(), seq_end = seq.end(); + while ((i != seq.end()) && is_a(i->rest) && i->coeff.info(info_flags::integer)) + ++i; + if (i == seq_end) { + setflag(status_flags::expanded); + return *this; + } + } + + // do not rename indices if the object has no indices at all + if ((!(options & expand_options::expand_rename_idx)) && + this->info(info_flags::has_indices)) + options |= expand_options::expand_rename_idx; + + const bool skip_idx_rename = !(options & expand_options::expand_rename_idx); + // First, expand the children std::auto_ptr expanded_seqp = expandchildren(options); const epvector & expanded_seq = (expanded_seqp.get() ? *expanded_seqp : seq); @@ -966,28 +1066,34 @@ ex mul::expand(unsigned options) const ex tmp_accu = (new add(distrseq, add1.overall_coeff*add2.overall_coeff))->setflag(status_flags::dynallocated); exvector add1_dummy_indices, add2_dummy_indices, add_indices; + lst dummy_subs; - for (epvector::const_iterator i=add1begin; i!=add1end; ++i) { - add_indices = get_all_dummy_indices_safely(i->rest); - add1_dummy_indices.insert(add1_dummy_indices.end(), add_indices.begin(), add_indices.end()); - } - for (epvector::const_iterator i=add2begin; i!=add2end; ++i) { - add_indices = get_all_dummy_indices_safely(i->rest); - add2_dummy_indices.insert(add2_dummy_indices.end(), add_indices.begin(), add_indices.end()); - } + if (!skip_idx_rename) { + for (epvector::const_iterator i=add1begin; i!=add1end; ++i) { + add_indices = get_all_dummy_indices_safely(i->rest); + add1_dummy_indices.insert(add1_dummy_indices.end(), add_indices.begin(), add_indices.end()); + } + for (epvector::const_iterator i=add2begin; i!=add2end; ++i) { + add_indices = get_all_dummy_indices_safely(i->rest); + add2_dummy_indices.insert(add2_dummy_indices.end(), add_indices.begin(), add_indices.end()); + } - sort(add1_dummy_indices.begin(), add1_dummy_indices.end(), ex_is_less()); - sort(add2_dummy_indices.begin(), add2_dummy_indices.end(), ex_is_less()); - lst dummy_subs = rename_dummy_indices_uniquely(add1_dummy_indices, add2_dummy_indices); + sort(add1_dummy_indices.begin(), add1_dummy_indices.end(), ex_is_less()); + sort(add2_dummy_indices.begin(), add2_dummy_indices.end(), ex_is_less()); + dummy_subs = rename_dummy_indices_uniquely(add1_dummy_indices, add2_dummy_indices); + } // Multiply explicitly all non-numeric terms of add1 and add2: for (epvector::const_iterator i2=add2begin; i2!=add2end; ++i2) { // We really have to combine terms here in order to compactify // the result. Otherwise it would become waayy tooo bigg. - numeric oc; - distrseq.clear(); - ex i2_new = (dummy_subs.op(0).nops()>0? - i2->rest.subs((lst)dummy_subs.op(0), (lst)dummy_subs.op(1), subs_options::no_pattern) : i2->rest); + numeric oc(*_num0_p); + epvector distrseq2; + distrseq2.reserve(add1.seq.size()); + const ex i2_new = (skip_idx_rename || (dummy_subs.op(0).nops() == 0) ? + i2->rest : + i2->rest.subs(ex_to(dummy_subs.op(0)), + ex_to(dummy_subs.op(1)), subs_options::no_pattern)); for (epvector::const_iterator i1=add1begin; i1!=add1end; ++i1) { // Don't push_back expairs which might have a rest that evaluates to a numeric, // since that would violate an invariant of expairseq: @@ -995,13 +1101,12 @@ ex mul::expand(unsigned options) const if (is_exactly_a(rest)) { oc += ex_to(rest).mul(ex_to(i1->coeff).mul(ex_to(i2->coeff))); } else { - distrseq.push_back(expair(rest, ex_to(i1->coeff).mul_dyn(ex_to(i2->coeff)))); + distrseq2.push_back(expair(rest, ex_to(i1->coeff).mul_dyn(ex_to(i2->coeff)))); } } - tmp_accu += (new add(distrseq, oc))->setflag(status_flags::dynallocated); - } + tmp_accu += (new add(distrseq2, oc))->setflag(status_flags::dynallocated); + } last_expanded = tmp_accu; - } else { if (!last_expanded.is_equal(_ex1)) non_adds.push_back(split_ex_to_pair(last_expanded)); @@ -1019,12 +1124,18 @@ ex mul::expand(unsigned options) const size_t n = last_expanded.nops(); exvector distrseq; distrseq.reserve(n); - exvector va = get_all_dummy_indices_safely(mul(non_adds)); - sort(va.begin(), va.end(), ex_is_less()); + exvector va; + if (! skip_idx_rename) { + va = get_all_dummy_indices_safely(mul(non_adds)); + sort(va.begin(), va.end(), ex_is_less()); + } for (size_t i=0; isetflag(status_flags::dynallocated); if (can_be_further_expanded(term)) { distrseq.push_back(term.expand());