]> www.ginac.de Git - ginac.git/blobdiff - ginac/mul.cpp
* mul::expand(): Fix bug in aggressive version of expansion of two sums
[ginac.git] / ginac / mul.cpp
index 542e80236b048d9d5acdc3596e441eaa672775a3..28233b302ebc1b1485b390c055df10586136c6c7 100644 (file)
@@ -3,7 +3,7 @@
  *  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
@@ -20,6 +20,7 @@
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include <iostream>
 #include <vector>
 #include <stdexcept>
 
@@ -28,7 +29,6 @@
 #include "power.h"
 #include "matrix.h"
 #include "archive.h"
-#include "debugmsg.h"
 #include "utils.h"
 
 namespace GiNaC {
@@ -36,12 +36,11 @@ namespace GiNaC {
 GINAC_IMPLEMENT_REGISTERED_CLASS(mul, expairseq)
 
 //////////
-// default ctor, dctor, copy ctor assignment operator and helpers
+// default ctor, dtor, copy ctor, assignment operator and helpers
 //////////
 
 mul::mul()
 {
-       debugmsg("mul default ctor",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
 }
 
@@ -56,34 +55,30 @@ DEFAULT_DESTROY(mul)
 
 mul::mul(const ex & lh, const ex & rh)
 {
-       debugmsg("mul ctor from ex,ex",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
-       overall_coeff = _ex1();
+       overall_coeff = _ex1;
        construct_from_2_ex(lh,rh);
        GINAC_ASSERT(is_canonical());
 }
 
 mul::mul(const exvector & v)
 {
-       debugmsg("mul ctor from exvector",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
-       overall_coeff = _ex1();
+       overall_coeff = _ex1;
        construct_from_exvector(v);
        GINAC_ASSERT(is_canonical());
 }
 
 mul::mul(const epvector & v)
 {
-       debugmsg("mul ctor from epvector",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
-       overall_coeff = _ex1();
+       overall_coeff = _ex1;
        construct_from_epvector(v);
        GINAC_ASSERT(is_canonical());
 }
 
 mul::mul(const epvector & v, const ex & oc)
 {
-       debugmsg("mul ctor from epvector,ex",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
        overall_coeff = oc;
        construct_from_epvector(v);
@@ -92,7 +87,6 @@ mul::mul(const epvector & v, const ex & oc)
 
 mul::mul(epvector * vp, const ex & oc)
 {
-       debugmsg("mul ctor from epvector *,ex",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
        GINAC_ASSERT(vp!=0);
        overall_coeff = oc;
@@ -103,14 +97,13 @@ mul::mul(epvector * vp, const ex & oc)
 
 mul::mul(const ex & lh, const ex & mh, const ex & rh)
 {
-       debugmsg("mul ctor from ex,ex,ex",LOGLEVEL_CONSTRUCT);
        tinfo_key = TINFO_mul;
        exvector factors;
        factors.reserve(3);
        factors.push_back(lh);
        factors.push_back(mh);
        factors.push_back(rh);
-       overall_coeff = _ex1();
+       overall_coeff = _ex1;
        construct_from_exvector(factors);
        GINAC_ASSERT(is_canonical());
 }
@@ -129,8 +122,6 @@ DEFAULT_ARCHIVING(mul)
 
 void mul::print(const print_context & c, unsigned level) const
 {
-       debugmsg("mul print", LOGLEVEL_PRINT);
-
        if (is_a<print_tree>(c)) {
 
                inherited::print(c, level);
@@ -140,7 +131,7 @@ void mul::print(const print_context & c, unsigned level) const
                if (precedence() <= level)
                        c.s << "(";
 
-               if (!overall_coeff.is_equal(_ex1())) {
+               if (!overall_coeff.is_equal(_ex1)) {
                        overall_coeff.print(c, precedence());
                        c.s << "*";
                }
@@ -150,7 +141,7 @@ void mul::print(const print_context & c, unsigned level) const
                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 (it == seq.begin() && ex_to<numeric>(it->coeff).is_integer() && it->coeff.info(info_flags::negative)) {
                                if (is_a<print_csrc_cl_N>(c))
                                        c.s << "recip(";
                                else
@@ -158,7 +149,7 @@ void mul::print(const print_context & c, unsigned level) const
                        }
 
                        // 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 {
                                // Outer parens around ex needed for broken gcc-2.95 parser:
@@ -168,7 +159,7 @@ void mul::print(const print_context & c, unsigned level) const
                        // 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 (ex_to<numeric>(it->coeff).is_integer() && it->coeff.info(info_flags::negative))
                                        c.s << "/";
                                else
                                        c.s << "*";
@@ -178,6 +169,14 @@ void mul::print(const print_context & c, unsigned level) const
                if (precedence() <= level)
                        c.s << ")";
 
+       } else if (is_a<print_python_repr>(c)) {
+               c.s << class_name() << '(';
+               op(0).print(c);
+               for (unsigned i=1; i<nops(); ++i) {
+                       c.s << ',';
+                       op(i).print(c);
+               }
+               c.s << ')';
        } else {
 
                if (precedence() <= level) {
@@ -193,8 +192,8 @@ void mul::print(const print_context & c, unsigned level) const
                numeric coeff = ex_to<numeric>(overall_coeff);
                if (coeff.csgn() == -1)
                        c.s << '-';
-               if (!coeff.is_equal(_num1()) &&
-                       !coeff.is_equal(_num_1())) {
+               if (!coeff.is_equal(_num1) &&
+                       !coeff.is_equal(_num_1)) {
                        if (coeff.is_rational()) {
                                if (coeff.is_negative())
                                        (-coeff).print(c);
@@ -327,7 +326,7 @@ ex mul::coeff(const ex & s, int n) const
                return (new mul(coeffseq))->setflag(status_flags::dynallocated);
        }
        
-       return _ex0();
+       return _ex0;
 }
 
 /** Perform automatic term rewriting rules in this class.  In the following
@@ -341,8 +340,6 @@ ex mul::coeff(const ex & s, int n) const
  *  @param level cut-off in recursive evaluation */
 ex mul::eval(int level) const
 {
-       debugmsg("mul eval",LOGLEVEL_MEMBER_FUNCTION);
-       
        epvector *evaled_seqp = evalchildren(level);
        if (evaled_seqp) {
                // do more evaluation later
@@ -353,12 +350,12 @@ ex mul::eval(int level) const
 #ifdef DO_GINAC_ASSERT
        epvector::const_iterator i = seq.begin(), end = seq.end();
        while (i != end) {
-               GINAC_ASSERT((!is_ex_exactly_of_type(i->rest, mul)) ||
+               GINAC_ASSERT((!is_exactly_a<mul>(i->rest)) ||
                             (!(ex_to<numeric>(i->coeff).is_integer())));
                GINAC_ASSERT(!(i->is_canonical_numeric()));
                if (is_ex_exactly_of_type(recombine_pair_to_ex(*i), numeric))
                    print(print_tree(std::cerr));
-               GINAC_ASSERT(!is_ex_exactly_of_type(recombine_pair_to_ex(*i), numeric));
+               GINAC_ASSERT(!is_exactly_a<numeric>(recombine_pair_to_ex(*i)));
                /* for paranoia */
                expair p = split_ex_to_pair(recombine_pair_to_ex(*i));
                GINAC_ASSERT(p.rest.is_equal(i->rest));
@@ -370,23 +367,23 @@ ex mul::eval(int level) const
        
        if (flags & status_flags::evaluated) {
                GINAC_ASSERT(seq.size()>0);
-               GINAC_ASSERT(seq.size()>1 || !overall_coeff.is_equal(_ex1()));
+               GINAC_ASSERT(seq.size()>1 || !overall_coeff.is_equal(_ex1));
                return *this;
        }
        
        int seq_size = seq.size();
        if (overall_coeff.is_zero()) {
                // *(...,x;0) -> 0
-               return _ex0();
+               return _ex0;
        } else if (seq_size==0) {
                // *(;c) -> c
                return overall_coeff;
-       } else if (seq_size==1 && overall_coeff.is_equal(_ex1())) {
+       } else if (seq_size==1 && overall_coeff.is_equal(_ex1)) {
                // *(x;1) -> x
                return recombine_pair_to_ex(*(seq.begin()));
        } else if ((seq_size==1) &&
                   is_ex_exactly_of_type((*seq.begin()).rest,add) &&
-                  ex_to<numeric>((*seq.begin()).coeff).is_equal(_num1())) {
+                  ex_to<numeric>((*seq.begin()).coeff).is_equal(_num1)) {
                // *(+(x,y,...);c) -> +(*(x,c),*(y,c),...) (c numeric(), no powers of +())
                const add & addref = ex_to<add>((*seq.begin()).rest);
                epvector *distrseq = new epvector();
@@ -428,7 +425,7 @@ ex mul::evalf(int level) const
 ex mul::evalm(void) const
 {
        // numeric*matrix
-       if (seq.size() == 1 && seq[0].coeff.is_equal(_ex1())
+       if (seq.size() == 1 && seq[0].coeff.is_equal(_ex1)
         && is_ex_of_type(seq[0].rest, matrix))
                return ex_to<matrix>(seq[0].rest).mul(ex_to<numeric>(overall_coeff));
 
@@ -495,7 +492,7 @@ ex mul::derivative(const symbol & s) const
        epvector::const_iterator i = seq.begin(), end = seq.end();
        epvector::iterator i2 = mulseq.begin();
        while (i != end) {
-               expair ep = split_ex_to_pair(power(i->rest, i->coeff - _ex1()) *
+               expair ep = split_ex_to_pair(power(i->rest, i->coeff - _ex1) *
                                             i->rest.diff(s));
                ep.swap(*i2);
                addseq.push_back((new mul(mulseq, overall_coeff * i->coeff))->setflag(status_flags::dynallocated));
@@ -581,7 +578,7 @@ expair mul::split_ex_to_pair(const ex & e) const
                if (is_ex_exactly_of_type(powerref.exponent,numeric))
                        return expair(powerref.basis,powerref.exponent);
        }
-       return expair(e,_ex1());
+       return expair(e,_ex1);
 }
        
 expair mul::combine_ex_with_coeff_to_pair(const ex & e,
@@ -591,7 +588,7 @@ expair mul::combine_ex_with_coeff_to_pair(const ex & e,
        // we create a temporary power object
        // otherwise it would be hard to correctly simplify
        // expression like (4^(1/3))^(3/2)
-       if (are_ex_trivially_equal(c,_ex1()))
+       if (are_ex_trivially_equal(c,_ex1))
                return split_ex_to_pair(e);
        
        return split_ex_to_pair(power(e,c));
@@ -604,7 +601,7 @@ expair mul::combine_pair_with_coeff_to_pair(const expair & p,
        // we create a temporary power object
        // otherwise it would be hard to correctly simplify
        // expression like (4^(1/3))^(3/2)
-       if (are_ex_trivially_equal(c,_ex1()))
+       if (are_ex_trivially_equal(c,_ex1))
                return p;
        
        return split_ex_to_pair(power(recombine_pair_to_ex(p),c));
@@ -612,7 +609,7 @@ expair mul::combine_pair_with_coeff_to_pair(const expair & p,
        
 ex mul::recombine_pair_to_ex(const expair & p) const
 {
-       if (ex_to<numeric>(p.coeff).is_equal(_num1())) 
+       if (ex_to<numeric>(p.coeff).is_equal(_num1)) 
                return p.rest;
        else
                return power(p.rest,p.coeff);
@@ -633,7 +630,7 @@ bool mul::expair_needs_further_processing(epp it)
                        *it = ep;
                        return true;
                }
-               if (ex_to<numeric>((*it).coeff).is_equal(_num1())) {
+               if (ex_to<numeric>((*it).coeff).is_equal(_num1)) {
                        // combined pair has coeff 1 and must be moved to the end
                        return true;
                }
@@ -643,31 +640,31 @@ bool mul::expair_needs_further_processing(epp it)
 
 ex mul::default_overall_coeff(void) const
 {
-       return _ex1();
+       return _ex1;
 }
 
 void mul::combine_overall_coeff(const ex & c)
 {
-       GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       GINAC_ASSERT(is_ex_exactly_of_type(c,numeric));
+       GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
+       GINAC_ASSERT(is_exactly_a<numeric>(c));
        overall_coeff = ex_to<numeric>(overall_coeff).mul_dyn(ex_to<numeric>(c));
 }
 
 void mul::combine_overall_coeff(const ex & c1, const ex & c2)
 {
-       GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       GINAC_ASSERT(is_ex_exactly_of_type(c1,numeric));
-       GINAC_ASSERT(is_ex_exactly_of_type(c2,numeric));
+       GINAC_ASSERT(is_exactly_a<numeric>(overall_coeff));
+       GINAC_ASSERT(is_exactly_a<numeric>(c1));
+       GINAC_ASSERT(is_exactly_a<numeric>(c2));
        overall_coeff = ex_to<numeric>(overall_coeff).mul_dyn(ex_to<numeric>(c1).power(ex_to<numeric>(c2)));
 }
 
 bool mul::can_make_flat(const expair & p) const
 {
-       GINAC_ASSERT(is_ex_exactly_of_type(p.coeff,numeric));
+       GINAC_ASSERT(is_exactly_a<numeric>(p.coeff));
        // this assertion will probably fail somewhere
        // it would require a more careful make_flat, obeying the power laws
        // probably should return true only if p.coeff is integer
-       return ex_to<numeric>(p.coeff).is_equal(_num1());
+       return ex_to<numeric>(p.coeff).is_equal(_num1);
 }
 
 ex mul::expand(unsigned options) const
@@ -680,28 +677,87 @@ ex mul::expand(unsigned options) const
        // with the next one that is found while collecting the factors which are
        // not sums
        int number_of_adds = 0;
-       ex last_expanded = _ex1();
+       ex last_expanded = _ex1;
        epvector non_adds;
        non_adds.reserve(expanded_seq.size());
        epvector::const_iterator cit = expanded_seq.begin(), last = expanded_seq.end();
        while (cit != last) {
                if (is_ex_exactly_of_type(cit->rest, add) &&
-                       (cit->coeff.is_equal(_ex1()))) {
+                       (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;
@@ -756,7 +812,7 @@ ex mul::expand(unsigned options) const
  *  pointer, if sequence is unchanged. */
 epvector * mul::expandchildren(unsigned options) const
 {
-       epvector::const_iterator last = seq.end();
+       const epvector::const_iterator last = seq.end();
        epvector::const_iterator cit = seq.begin();
        while (cit!=last) {
                const ex & factor = recombine_pair_to_ex(*cit);