Require TPR file for gmx cluster

The program crashes without it, so it wasn't
optional.

Fixes #2170.

Change-Id: I63af728eea047dd4c3b11d890d507473109a7279

diff --git a/src/gromacs/gmxana/gmx_cluster.cpp b/src/gromacs/gmxana/gmx_cluster.cpp
index 96cdf384ca7217507cfbb7dea6c4d8b1a756e145..9e4838c5bd848c7d595dcd3891f37f192e3b0701 100644 (file)
--- a/src/gromacs/gmxana/gmx_cluster.cpp
+++ b/src/gromacs/gmxana/gmx_cluster.cpp
@@ -1476,7 +1476,7 @@ int gmx_cluster(int argc, char *argv[])
     };
     t_filenm          fnm[] = {
         { efTRX, "-f",     nullptr,        ffOPTRD },
-        { efTPS, "-s",     nullptr,        ffOPTRD },
+        { efTPS, "-s",     nullptr,        ffREAD },
         { efNDX, nullptr,     nullptr,        ffOPTRD },
         { efXPM, "-dm",   "rmsd",       ffOPTRD },
         { efXPM, "-om",   "rmsd-raw",   ffWRITE },