--- trunk/OOPSE-1.0/libmdtools/mpiSimulation.cpp	2004/07/16 18:58:03	1334
+++ trunk/OOPSE-1.0/libmdtools/mpiSimulation.cpp	2004/07/26 14:36:05	1411
@@ -84,8 +84,22 @@ void mpiSimulation::divideLabor( ){
   parallelData->nGroupsGlobal = entryPlug->ngroup;
   parallelData->nMolGlobal = entryPlug->n_mol;
 
-  myRandom = new randomSPRNG( baseSeed );
+  if (parallelData->nProcessors > parallelData->nMolGlobal) {
+    sprintf( painCave.errMsg,
+             "nProcessors (%d) > nMol (%d)\n"
+             "\tThe number of processors is larger than\n"
+             "\tthe number of molecules.  This will not result in a \n"
+             "\tusable division of atoms for force decomposition.\n"
+             "\tEither try a smaller number of processors, or run the\n"
+             "\tsingle-processor version of OOPSE.\n",
+             parallelData->nProcessors, parallelData->nMolGlobal );
+    painCave.isFatal = 1;
+    simError();
+  }
 
+  myRandom = new randomSPRNG( baseSeed );  
+
+
   a = 3.0 * (double)parallelData->nMolGlobal / (double)parallelData->nAtomsGlobal;
 
   // Initialize things that we'll send out later: