[nitpick] power::expand_add(): don't use int instead of std::size_t.

[ginac.git] / ginac / power.cpp

diff --git a/ginac/power.cpp b/ginac/power.cpp
index 68bec71c949c4866fd2c949c2c9df0db78ec2112..a4a33c576ca415e0a3baa7e6b089fd8dae22b81f 100644 (file)
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
 
 /*
- *  GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2008 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
@@ -241,6 +241,21 @@ bool power::info(unsigned inf) const
                               basis.info(inf);
                case info_flags::expanded:
                        return (flags & status_flags::expanded);
+               case info_flags::has_indices: {
+                       if (flags & status_flags::has_indices)
+                               return true;
+                       else if (flags & status_flags::has_no_indices)
+                               return false;
+                       else if (basis.info(info_flags::has_indices)) {
+                               setflag(status_flags::has_indices);
+                               clearflag(status_flags::has_no_indices);
+                               return true;
+                       } else {
+                               clearflag(status_flags::has_indices);
+                               setflag(status_flags::has_no_indices);
+                               return false;
+                       }
+               }
        }
        return inherited::info(inf);
 }
@@ -491,8 +506,8 @@ ex power::eval(int level) const
                // (2*x + 6*y)^(-4) -> 1/16*(x + 3*y)^(-4)
                if (num_exponent->is_integer() && is_exactly_a<add>(ebasis)) {
                        numeric icont = ebasis.integer_content();
-                       const numeric& lead_coeff = 
-                               ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div_dyn(icont);
+                       const numeric lead_coeff = 
+                               ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div(icont);
 
                        const bool canonicalizable = lead_coeff.is_integer();
                        const bool unit_normal = lead_coeff.is_pos_integer();
@@ -620,7 +635,7 @@ bool power::has(const ex & other, unsigned options) const
 }
 
 // from mul.cpp
-extern bool tryfactsubs(const ex &, const ex &, int &, lst &);
+extern bool tryfactsubs(const ex &, const ex &, int &, exmap&);
 
 ex power::subs(const exmap & m, unsigned options) const
 {      
@@ -636,9 +651,13 @@ ex power::subs(const exmap & m, unsigned options) const
 
        for (exmap::const_iterator it = m.begin(); it != m.end(); ++it) {
                int nummatches = std::numeric_limits<int>::max();
-               lst repls;
-               if (tryfactsubs(*this, it->first, nummatches, repls))
-                       return (ex_to<basic>((*this) * power(it->second.subs(ex(repls), subs_options::no_pattern) / it->first.subs(ex(repls), subs_options::no_pattern), nummatches))).subs_one_level(m, options);
+               exmap repls;
+               if (tryfactsubs(*this, it->first, nummatches, repls)) {
+                       ex anum = it->second.subs(repls, subs_options::no_pattern);
+                       ex aden = it->first.subs(repls, subs_options::no_pattern);
+                       ex result = (*this)*power(anum/aden, nummatches);
+                       return (ex_to<basic>(result)).subs_one_level(m, options);
+               }
        }
 
        return subs_one_level(m, options);
@@ -757,9 +776,12 @@ tinfo_t power::return_type_tinfo() const
 
 ex power::expand(unsigned options) const
 {
-       if (options == 0 && (flags & status_flags::expanded))
+       if (is_a<symbol>(basis) && exponent.info(info_flags::integer)) {
+               // A special case worth optimizing.
+               setflag(status_flags::expanded);
                return *this;
-       
+       }
+
        const ex expanded_basis = basis.expand(options);
        const ex expanded_exponent = exponent.expand(options);
        
@@ -846,7 +868,6 @@ ex power::expand_add(const add & a, int n, unsigned options) const
        intvector k(m-1);
        intvector k_cum(m-1); // k_cum[l]:=sum(i=0,l,k[l]);
        intvector upper_limit(m-1);
-       int l;
 
        for (size_t l=0; l<m-1; ++l) {
                k[l] = 0;
@@ -857,7 +878,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
        while (true) {
                exvector term;
                term.reserve(m+1);
-               for (l=0; l<m-1; ++l) {
+               for (std::size_t l = 0; l < m - 1; ++l) {
                        const ex & b = a.op(l);
                        GINAC_ASSERT(!is_exactly_a<add>(b));
                        GINAC_ASSERT(!is_exactly_a<power>(b) ||
@@ -872,7 +893,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
                                term.push_back(power(b,k[l]));
                }
 
-               const ex & b = a.op(l);
+               const ex & b = a.op(m - 1);
                GINAC_ASSERT(!is_exactly_a<add>(b));
                GINAC_ASSERT(!is_exactly_a<power>(b) ||
                             !is_exactly_a<numeric>(ex_to<power>(b).exponent) ||
@@ -886,7 +907,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
                        term.push_back(power(b,n-k_cum[m-2]));
 
                numeric f = binomial(numeric(n),numeric(k[0]));
-               for (l=1; l<m-1; ++l)
+               for (std::size_t l = 1; l < m - 1; ++l)
                        f *= binomial(numeric(n-k_cum[l-1]),numeric(k[l]));
 
                term.push_back(f);
@@ -894,12 +915,19 @@ ex power::expand_add(const add & a, int n, unsigned options) const
                result.push_back(ex((new mul(term))->setflag(status_flags::dynallocated)).expand(options));
 
                // increment k[]
-               l = m-2;
-               while ((l>=0) && ((++k[l])>upper_limit[l])) {
+               bool done = false;
+               std::size_t l = m - 2;
+               while ((++k[l]) > upper_limit[l]) {
                        k[l] = 0;
-                       --l;
+                       if (l != 0)
+                               --l;
+                       else {
+                               done = true;
+                               break;
+                       }
                }
-               if (l<0) break;
+               if (done)
+                       break;
 
                // recalc k_cum[] and upper_limit[]
                k_cum[l] = (l==0 ? k[0] : k_cum[l-1]+k[l]);
@@ -992,8 +1020,13 @@ ex power::expand_mul(const mul & m, const numeric & n, unsigned options, bool fr
                return _ex1;
        }
 
+       // do not bother to rename indices if there are no any.
+       if ((!(options & expand_options::expand_rename_idx)) 
+                       && m.info(info_flags::has_indices))
+               options |= expand_options::expand_rename_idx;
        // Leave it to multiplication since dummy indices have to be renamed
-       if (get_all_dummy_indices(m).size() > 0 && n.is_positive()) {
+       if ((options & expand_options::expand_rename_idx) &&
+               (get_all_dummy_indices(m).size() > 0) && n.is_positive()) {
                ex result = m;
                exvector va = get_all_dummy_indices(m);
                sort(va.begin(), va.end(), ex_is_less());