From 1003bf77356d9da275af09fe6845516db329169b Mon Sep 17 00:00:00 2001
From: Arne Morten Kvarving <arne.morten.kvarving@sintef.no>
Date: Tue, 25 Apr 2023 15:07:58 +0200
Subject: [PATCH] added: explicitly check that number of processes matches
 .OPMRST file

while the grid hash check would pick this up as well, it's better
to emit an explicit error message
---
 .../flow/SimulatorFullyImplicitBlackoilEbos.hpp       | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/opm/simulators/flow/SimulatorFullyImplicitBlackoilEbos.hpp b/opm/simulators/flow/SimulatorFullyImplicitBlackoilEbos.hpp
index ea0624f7e..c8114b504 100644
--- a/opm/simulators/flow/SimulatorFullyImplicitBlackoilEbos.hpp
+++ b/opm/simulators/flow/SimulatorFullyImplicitBlackoilEbos.hpp
@@ -644,6 +644,17 @@ protected:
         const std::string groupName = "/report_step/" + std::to_string(loadStep_);
         reader.read(timer, groupName, "simulator_timer", HDF5File::DataSetMode::ROOT_ONLY);
 
+        std::tuple<std::array<std::string,5>,int> header;
+        reader.read(header, "/", "simulator_info", HDF5File::DataSetMode::ROOT_ONLY);
+        const auto& [strings, procs] = header;
+
+        if (EclGenericVanguard::comm().size() != procs) {
+            throw std::runtime_error("Number of processes (procs=" +
+                                     std::to_string(EclGenericVanguard::comm().size()) +
+                                     ") does not match .OPMRST file (procs=" +
+                                     std::to_string(procs) + ")");
+        }
+
         if (EclGenericVanguard::comm().size() > 1) {
             std::size_t stored_hash;
             reader.read(stored_hash, "/", "grid_checksum");