Fix UB when generating local indices for constraints

[alexxy/gromacs.git] / src / gromacs / essentialdynamics / edsam.cpp

diff --git a/src/gromacs/essentialdynamics/edsam.cpp b/src/gromacs/essentialdynamics/edsam.cpp
index 605c36d485780c12ea150b839618bf0d190b8183..48dafd3d0ab91ccb97649b438728ad917c2b9409 100644 (file)
--- a/src/gromacs/essentialdynamics/edsam.cpp
+++ b/src/gromacs/essentialdynamics/edsam.cpp
@@ -1960,7 +1960,7 @@ static void translate_and_rotate(rvec*  x,        /* The positions to be transla
 
 /* Gets the rms deviation of the positions to the structure s */
 /* fit_to_structure has to be called before calling this routine! */
-static real rmsd_from_structure(rvec* x,           /* The positions under consideration */
+static real rmsd_from_structure(rvec*           x, /* The positions under consideration */
                                 struct gmx_edx* s) /* The structure from which the rmsd shall be computed */
 {
     real rmsd = 0.0;
@@ -3062,14 +3062,15 @@ std::unique_ptr<gmx::EssentialDynamics> init_edsam(const gmx::MDLogger&        m
 
     } /* end of MASTER only section */
 
-    if (PAR(cr))
+    if (haveDDAtomOrdering(*cr))
     {
-        /* Broadcast the essential dynamics / flooding data to all nodes */
+        /* Broadcast the essential dynamics / flooding data to all nodes.
+         * In a single-rank case, only the necessary memory allocation is done. */
         broadcast_ed_data(cr, ed);
     }
     else
     {
-        /* In the single-CPU case, point the local atom numbers pointers to the global
+        /* In the non-DD case, point the local atom numbers pointers to the global
          * one, so that we can use the same notation in serial and parallel case: */
         /* Loop over all ED data sets (usually only one, though) */
         for (auto edi = ed->edpar.begin(); edi != ed->edpar.end(); ++edi)