X-Git-Url: http://mmka.chem.univ.gda.pl/gitweb/?a=blobdiff_plain;f=source%2Funres%2Fsrc_MD-M%2Fintcor.f;h=9195f8a5cc4b5ab51fabfd2a8cb0083d74e097bc;hb=294e17e0754856766b19c5296e6f20d2bfab579f;hp=a3cd5d0bbbb65be53f175a1ef35f311524a4a959;hpb=478a9d9a1c99eb3f4bc4ca676ff3162bdd01d633;p=unres.git

diff --git a/source/unres/src_MD-M/intcor.f b/source/unres/src_MD-M/intcor.f
index a3cd5d0..9195f8a 100644
--- a/source/unres/src_MD-M/intcor.f
+++ b/source/unres/src_MD-M/intcor.f
@@ -17,7 +17,11 @@ c
       z23=c(3,i3)-c(3,i2)
       vnorm=dsqrt(x12*x12+y12*y12+z12*z12)
       wnorm=dsqrt(x23*x23+y23*y23+z23*z23)
+      if ((vnorm.eq.0.0).or.(wnorm.eq.0.0)) then
+      scalar=1.0
+      else
       scalar=(x12*x23+y12*y23+z12*z23)/(vnorm*wnorm)
+      endif
       alpha=arcos(scalar)
       return
       end