- powers with negative exponents are printed as fractions in the LaTeX output

[ginac.git] / ginac / mul.cpp

diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index 211855a6613d2cc9dfabe370ae6272e7b4460143..f60937069bea7dc00abd5e0bbe8dd3947af19a6a 100644 (file)
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -193,8 +193,6 @@ void mul::print(const print_context & c, unsigned level) const
                                c.s << "(";
                }
 
-               bool first = true;
-
                // First print the overall numeric coefficient
                numeric coeff = ex_to<numeric>(overall_coeff);
                if (coeff.csgn() == -1)
@@ -220,17 +218,51 @@ void mul::print(const print_context & c, unsigned level) const
 
                // 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) {