Preserve flash diagnostics on non-root MPI ranks

Enable Flow's existing per-rank debug logging and merger whenever flash diagnostics are requested. Document where flash verbosity is written and apply the project formatting to the diagnostic output.

Author: GitPaean

opm/models/ptflash/flashintensivequantities.hh

@@ -202,15 +202,17 @@ public:
         if (flashVerbosity >= 5) {
             std::string phaseCompositions;
             for (unsigned compIdx = 0; compIdx < numComponents; ++compIdx) {
-                fmt::format_to(std::back_inserter(phaseCompositions),
-                               "  component {}: x = {}, y = {}\n",
-                               compIdx,
-                               getValue(fluidState_.moleFraction(FluidSystem::oilPhaseIdx, compIdx)),
-                               getValue(fluidState_.moleFraction(FluidSystem::gasPhaseIdx, compIdx)));
+                fmt::format_to(
+                    std::back_inserter(phaseCompositions),
+                    "  component {}: x = {}, y = {}\n",
+                    compIdx,
+                    getValue(fluidState_.moleFraction(FluidSystem::oilPhaseIdx, compIdx)),
+                    getValue(fluidState_.moleFraction(FluidSystem::gasPhaseIdx, compIdx)));
             }
             OpmLog::debug(fmt::format("After the flash for cell {}: liquid fraction = {}\n{}",
                                       elemCtx.globalSpaceIndex(dofIdx, timeIdx),
-                                      getValue(fluidState_.L()), phaseCompositions));
+                                      getValue(fluidState_.L()),
+                                      phaseCompositions));
         }
 
         // Update phases
@@ -256,7 +258,10 @@ public:
                                       "oil saturation = {}, gas saturation = {}, "
                                       "oil molar volume = {}, gas molar volume = {}",
                                       elemCtx.globalSpaceIndex(dofIdx, timeIdx),
-                                      getValue(So), getValue(Sg), getValue(Vm_L), getValue(Vm_V)));
+                                      getValue(So),
+                                      getValue(Sg),
+                                      getValue(Vm_L),
+                                      getValue(Vm_V)));
         }
 
         /////////////

opm/models/ptflash/flashmodel.hh

@@ -233,8 +233,9 @@ public:
         Parameters::Register<Parameters::FlashTolerance<Scalar>>
             ("The maximum tolerance for the flash solver to "
              "consider the solution converged");
-        Parameters::Register<Parameters::FlashVerbosity>
-            ("Flash solver verbosity level");
+        Parameters::Register<Parameters::FlashVerbosity>(
+            "Flash solver verbosity level. Messages are written to the debug log and require "
+            "--debug-verbosity-level to be at least 1");
         Parameters::Register<Parameters::FlashTwoPhaseMethod>
             ("Method for solving vapor-liquid composition. Available options include: "
              "ssi, newton, ssi+newton");

opm/simulators/flow/FlowMain.hpp

@@ -26,6 +26,7 @@
 #include <opm/input/eclipse/EclipseState/IOConfig/IOConfig.hpp>
 #include <opm/input/eclipse/EclipseState/InitConfig/InitConfig.hpp>
 
+#include <opm/models/ptflash/flashparameters.hh>
 #include <opm/models/utils/start.hh>
 
 #include <opm/simulators/flow/Banners.hpp>
@@ -63,6 +64,19 @@ namespace Opm {
 
     class Deck;
 
+    namespace detail
+    {
+
+        inline bool allRanksDebugLoggingEnabled()
+        {
+            // FlashVerbosity is only registered by compositional models.
+            return Parameters::Get<Parameters::EnableLoggingFalloutWarning>()
+                || (Parameters::IsSet<Parameters::FlashVerbosity>(false)
+                    && (Parameters::Get<Parameters::FlashVerbosity>() > 0));
+        }
+
+    } // namespace detail
+
     // The FlowMain class is the standard fully implicit flow simulator.
     template <class TypeTag>
     class FlowMain
@@ -356,7 +370,7 @@ namespace Opm {
 
             detail::mergeParallelLogFiles(eclState().getIOConfig().getOutputDir(),
                                           Parameters::Get<Parameters::EclDeckFileName>(),
-                                          Parameters::Get<Parameters::EnableLoggingFalloutWarning>());
+                                          detail::allRanksDebugLoggingEnabled());
         }
 
         void setupModelSimulator()

opm/simulators/flow/Main.hpp

@@ -319,7 +319,7 @@ class Main
                            outputDir,
                            Parameters::Get<Parameters::OutputMode>(),
                            !Parameters::Get<Parameters::SchedRestart>(),
-                           Parameters::Get<Parameters::EnableLoggingFalloutWarning>(),
+                           detail::allRanksDebugLoggingEnabled(),
                            Parameters::Get<Parameters::ParsingStrictness>(),
                            Parameters::Get<Parameters::ActionParsingStrictness>(),
                            Parameters::Get<Parameters::InputSkipMode>(),