Added numerical evaluation for the functions tgamma, lgamma and beta.

[ginac.git] / ginac / inifcns_gamma.cpp

diff --git a/ginac/inifcns_gamma.cpp b/ginac/inifcns_gamma.cpp
index baed308d366fba1a571e24989deca9f4c6c818a5..c9adc19967ad37a4da71f91b1929103a0cd58586 100644 (file)
--- a/ginac/inifcns_gamma.cpp
+++ b/ginac/inifcns_gamma.cpp
@@ -221,7 +221,7 @@ static ex beta_evalf(const ex & x, const ex & y)
 {
        if (is_exactly_a<numeric>(x) && is_exactly_a<numeric>(y)) {
                try {
-                       return tgamma(ex_to<numeric>(x))*tgamma(ex_to<numeric>(y))/tgamma(ex_to<numeric>(x+y));
+                       return exp(lgamma(ex_to<numeric>(x))+lgamma(ex_to<numeric>(y))-lgamma(ex_to<numeric>(x+y)));
                } catch (const dunno &e) { }
        }