1/1/e expanded e but shouldn't
authorChristian Bauer <Christian.Bauer@uni-mainz.de>
Tue, 16 Dec 2003 17:52:06 +0000 (17:52 +0000)
committerChristian Bauer <Christian.Bauer@uni-mainz.de>
Tue, 16 Dec 2003 17:52:06 +0000 (17:52 +0000)
check/exam_paranoia.cpp
ginac/power.cpp
ginac/power.h

index 21d40c9aba562e42f11c1df0de304cebff0d2f45..cbab84dfe6d6fff7772032f7f4a22e7fc7d63e23 100644 (file)
@@ -426,6 +426,14 @@ static unsigned exam_paranoia16()
                ++result;
        }
 
+       e1 = a*(a+b);
+       e2 = pow(pow(e1, -1), -1);
+
+       if (e2.has(a*b)) {
+               clog << "double reciprocal expanded where it should not\n";
+               ++result;
+       }
+
        return result;
 }
 
index 2cff577eabdc80e55972a2c18dd68776e08b306e..fe18097b15f78bcea22898a0f224a241059c5755 100644 (file)
@@ -656,7 +656,7 @@ ex power::expand(unsigned options) const
        
        // (x*y)^n -> x^n * y^n
        if (is_exactly_a<mul>(expanded_basis))
-               return expand_mul(ex_to<mul>(expanded_basis), num_exponent, options);
+               return expand_mul(ex_to<mul>(expanded_basis), num_exponent, options, true);
        
        // cannot expand further
        if (are_ex_trivially_equal(basis,expanded_basis) && are_ex_trivially_equal(exponent,expanded_exponent))
@@ -713,7 +713,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
                                     !is_exactly_a<mul>(ex_to<power>(b).basis) ||
                                     !is_exactly_a<power>(ex_to<power>(b).basis));
                        if (is_exactly_a<mul>(b))
-                               term.push_back(expand_mul(ex_to<mul>(b), numeric(k[l]), options));
+                               term.push_back(expand_mul(ex_to<mul>(b), numeric(k[l]), options, true));
                        else
                                term.push_back(power(b,k[l]));
                }
@@ -727,7 +727,7 @@ ex power::expand_add(const add & a, int n, unsigned options) const
                             !is_exactly_a<mul>(ex_to<power>(b).basis) ||
                             !is_exactly_a<power>(ex_to<power>(b).basis));
                if (is_exactly_a<mul>(b))
-                       term.push_back(expand_mul(ex_to<mul>(b), numeric(n-k_cum[m-2]), options));
+                       term.push_back(expand_mul(ex_to<mul>(b), numeric(n-k_cum[m-2]), options, true));
                else
                        term.push_back(power(b,n-k_cum[m-2]));
 
@@ -787,7 +787,7 @@ ex power::expand_add_2(const add & a, unsigned options) const
                
                if (c.is_equal(_ex1)) {
                        if (is_exactly_a<mul>(r)) {
-                               sum.push_back(expair(expand_mul(ex_to<mul>(r), _num2, options),
+                               sum.push_back(expair(expand_mul(ex_to<mul>(r), _num2, options, true),
                                                     _ex1));
                        } else {
                                sum.push_back(expair((new power(r,_ex2))->setflag(status_flags::dynallocated),
@@ -795,7 +795,7 @@ ex power::expand_add_2(const add & a, unsigned options) const
                        }
                } else {
                        if (is_exactly_a<mul>(r)) {
-                               sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to<mul>(r), _num2, options),
+                               sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to<mul>(r), _num2, options, true),
                                                     ex_to<numeric>(c).power_dyn(_num2)));
                        } else {
                                sum.push_back(a.combine_ex_with_coeff_to_pair((new power(r,_ex2))->setflag(status_flags::dynallocated),
@@ -830,7 +830,7 @@ ex power::expand_add_2(const add & a, unsigned options) const
 
 /** Expand factors of m in m^n where m is a mul and n is and integer.
  *  @see power::expand */
-ex power::expand_mul(const mul & m, const numeric & n, unsigned options) const
+ex power::expand_mul(const mul & m, const numeric & n, unsigned options, bool from_expand) const
 {
        GINAC_ASSERT(n.is_integer());
 
@@ -850,7 +850,7 @@ ex power::expand_mul(const mul & m, const numeric & n, unsigned options) const
                        // it is safe not to call mul::combine_pair_with_coeff_to_pair()
                        // since n is an integer
                        numeric new_coeff = ex_to<numeric>(cit->coeff).mul(n);
-                       if (is_exactly_a<add>(cit->rest) && new_coeff.is_pos_integer()) {
+                       if (from_expand && is_exactly_a<add>(cit->rest) && new_coeff.is_pos_integer()) {
                                // this happens when e.g. (a+b)^(1/2) gets squared and
                                // the resulting product needs to be reexpanded
                                need_reexpand = true;
@@ -863,8 +863,9 @@ ex power::expand_mul(const mul & m, const numeric & n, unsigned options) const
        const mul & result = static_cast<const mul &>((new mul(distrseq, ex_to<numeric>(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated));
        if (need_reexpand)
                return ex(result).expand(options);
-       else
+       if (from_expand)
                return result.setflag(status_flags::expanded);
+       return result;
 }
 
 } // namespace GiNaC
index ff547e308cbdf02d30aa06791b3847e065ba6d62..eddcf2f8757d024c55ede192f212e9373e134893 100644 (file)
@@ -86,7 +86,7 @@ protected:
 
        ex expand_add(const add & a, int n, unsigned options) const;
        ex expand_add_2(const add & a, unsigned options) const;
-       ex expand_mul(const mul & m, const numeric & n, unsigned options) const;
+       ex expand_mul(const mul & m, const numeric & n, unsigned options, bool from_expand = false) const;
        
 // member variables