Allow using CPU PME with DD and GPU update

diff --git a/docs/release-notes/2021/2021.2.rst b/docs/release-notes/2021/2021.2.rst
index fbcdafdde05b763343dca1842fc9d36ad10fdf3a..00f1b31d4e01415ba4c224fc556a4da881c87b3f 100644 (file)
--- a/docs/release-notes/2021/2021.2.rst
+++ b/docs/release-notes/2021/2021.2.rst
@@ -82,3 +82,14 @@ Fix bond type in GROMOS force fields
 The bond type for C and +N in [ACE] was incorrect.
 
 :issue:`3995`
+
+
+Allow PME on CPU in runs with domain decomposition and GPU update
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+Relaxed a limitation which prevented running parallel runs with domain
+decomposition and GPU update to use the CPU for PME (as long as combined
+PP-PME ranks are used). This allows parallel runs to scale when the CPU
+resources are sufficient for PME.
+
+:issue:`4035`

diff --git a/src/gromacs/taskassignment/decidegpuusage.cpp b/src/gromacs/taskassignment/decidegpuusage.cpp
index 53ff94c3463707bd3cbe19173dde1d3155267a56..72d8e2a71aa58862801788cb9435c9a8e9999a85 100644 (file)
--- a/src/gromacs/taskassignment/decidegpuusage.cpp
+++ b/src/gromacs/taskassignment/decidegpuusage.cpp
@@ -573,11 +573,6 @@ bool decideWhetherToUseGpuForUpdate(const bool                     isDomainDecom
                     "small molecules, and box sizes close to half the pair-list cutoff are not "
                     "supported.\n ";
         }
-
-        if (pmeUsesCpu)
-        {
-            errorMessage += "With domain decomposition, PME must run fully on the GPU.\n";
-        }
     }
 
     if (havePmeOnlyRank)