From: Martin Kronbichler <martin.kronbichler@rub.de>
Date: Sun, 12 Nov 2023 21:51:50 +0000 (+0100)
Subject: SymmetricTensor: Minimalnumber of instructions for multiply by Tensor
X-Git-Tag: relicensing~302^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d7fad3a9ede8429d8aaf2cb3637d96f8006e563;p=dealii.git

SymmetricTensor: Minimalnumber of instructions for multiply by Tensor
---

diff --git a/include/deal.II/base/symmetric_tensor.h b/include/deal.II/base/symmetric_tensor.h
index fa61cdf567..c8b1245c08 100644
--- a/include/deal.II/base/symmetric_tensor.h
+++ b/include/deal.II/base/symmetric_tensor.h
@@ -4207,8 +4207,11 @@ operator*(const SymmetricTensor<2, dim, Number> &src1,
 {
   Tensor<1, dim, typename ProductType<Number, OtherNumber>::type> dest;
   for (unsigned int i = 0; i < dim; ++i)
-    for (unsigned int j = 0; j < dim; ++j)
-      dest[i] += src1[i][j] * src2[j];
+    {
+      dest[i] = src1[i][0] * src2[0];
+      for (unsigned int j = 1; j < dim; ++j)
+        dest[i] += src1[i][j] * src2[j];
+    }
   return dest;
 }