From: angelrca <angel.rcarballo@udc.es>
Date: Mon, 29 Jun 2015 09:26:33 +0000 (+0200)
Subject: Fix Functions::Monomial::gradient
X-Git-Tag: v8.3.0-rc1~84^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31215bbe3205ed08e95a39e78e3bc395ce2ea70b;p=dealii.git

Fix Functions::Monomial::gradient
---

diff --git a/source/base/function_lib.cc b/source/base/function_lib.cc
index 1ff631533a..6abfcbe38d 100644
--- a/source/base/function_lib.cc
+++ b/source/base/function_lib.cc
@@ -2146,12 +2146,21 @@ namespace Functions
       {
         double prod = 1;
         for (unsigned int s=0; s<dim; ++s)
-          prod *= (s==d
-                   ?
-                   exponents[s] * std::pow(p[s], exponents[s]-1)
-                   :
-                   std::pow(p[s], exponents[s]));
-
+          {
+            if ((s==d) && (exponents[s] == 0) && (p[s] == 0))
+              {
+                prod = 0;
+                break;
+              }
+            else
+              {
+                prod *= (s==d
+                         ?
+                         exponents[s] * std::pow(p[s], exponents[s]-1)
+                         :
+                         std::pow(p[s], exponents[s]));
+              }
+          }
         r[d] = prod;
       }