ENH: improve findInstance handling of negative times (#1112)

- normally findInstance will 'bottom out' with the constant directory
  while doing its reverse time search. This mechanism however fails
  when searching for negative start values (if there are none in the
  list). Add additional logic for this so that constant will also be
  used in these situations.

Note: to have decomposePar work for all times, may need the -constant option
to trigger the proper time list.

src/OpenFOAM/global/fileOperations/fileOperation/fileOperation.C

@@ -104,51 +104,51 @@ Foam::instantList Foam::fileOperation::sortTimes
 )
 {
     // Initialise instant list
-    instantList Times(dirEntries.size() + 1);
+    instantList times(dirEntries.size() + 1);
     label nTimes = 0;
 
     // Check for "constant"
     bool haveConstant = false;
-    forAll(dirEntries, i)
+    for (const fileName& dirName : dirEntries)
     {
-        if (dirEntries[i] == constantName)
+        if (dirName == constantName)
         {
-            Times[nTimes].value() = 0;
-            Times[nTimes].name() = dirEntries[i];
-            nTimes++;
             haveConstant = true;
+            times[nTimes].value() = 0;
+            times[nTimes].name() = constantName;
+            ++nTimes;
             break;
         }
     }
 
     // Read and parse all the entries in the directory
-    forAll(dirEntries, i)
+    for (const fileName& dirName : dirEntries)
     {
         scalar timeValue;
-        if (readScalar(dirEntries[i], timeValue))
+        if (readScalar(dirName, timeValue))
         {
-            Times[nTimes].value() = timeValue;
-            Times[nTimes].name() = dirEntries[i];
-            nTimes++;
+            times[nTimes].value() = timeValue;
+            times[nTimes].name() = dirName;
+            ++nTimes;
         }
     }
 
     // Reset the length of the times list
-    Times.setSize(nTimes);
+    times.setSize(nTimes);
 
     if (haveConstant)
     {
         if (nTimes > 2)
         {
-            std::sort(&Times[1], Times.end(), instant::less());
+            std::sort(&times[1], times.end(), instant::less());
         }
     }
     else if (nTimes > 1)
     {
-        std::sort(&Times[0], Times.end(), instant::less());
+        std::sort(&times[0], times.end(), instant::less());
     }
 
-    return Times;
+    return times;
 }
 
 
@@ -161,15 +161,15 @@ void Foam::fileOperation::mergeTimes
 {
     if (extraTimes.size())
     {
-        bool haveConstant =
+        const bool haveConstant =
         (
-            times.size() > 0
+            times.size()
          && times[0].name() == constantName
         );
 
-        bool haveExtraConstant =
+        const bool haveExtraConstant =
         (
-            extraTimes.size() > 0
+            extraTimes.size()
          && extraTimes[0].name() == constantName
         );
 
@@ -228,9 +228,7 @@ void Foam::fileOperation::mergeTimes
 
 bool Foam::fileOperation::isFileOrDir(const bool isFile, const fileName& f)
 {
-    return
-        (isFile && Foam::isFile(f))
-     || (!isFile && Foam::isDir(f));
+    return (isFile ? Foam::isFile(f) : Foam::isDir(f));
 }
 
 
@@ -431,10 +429,8 @@ Foam::autoPtr<Foam::fileOperation> Foam::fileOperation::New
     bool verbose
 )
 {
-    if (debug)
-    {
-        InfoInFunction << "Constructing fileHandler" << endl;
-    }
+    DebugInFunction
+        << "Constructing fileHandler" << endl;
 
     auto cstrIter = wordConstructorTablePtr_->cfind(handlerType);
 
@@ -570,15 +566,13 @@ Foam::fileName Foam::fileOperation::filePath(const fileName& fName) const
         }
         return fName;
     }
-    else
-    {
+
     if (debug)
     {
         Pout<< "fileOperation::filePath : Not found" << endl;
     }
     return fileName::null;
 }
-}
 
 
 Foam::label Foam::fileOperation::addWatch(const fileName& fName) const
@@ -755,13 +749,10 @@ Foam::IOobject Foam::fileOperation::findInstance
 
     if (exists(io))
     {
-        if (debug)
-        {
-            InfoInFunction
+        DebugInFunction
             << "Found exact match for \"" << io.name()
             << "\" in " << io.instance()/io.local()
             << endl;
-        }
 
         return io;
     }
@@ -770,9 +761,9 @@ Foam::IOobject Foam::fileOperation::findInstance
     // closest to and lower than current time
 
     instantList ts = time.times();
-    label instanceI;
+    label instanceI = ts.size()-1;
 
-    for (instanceI = ts.size()-1; instanceI >= 0; --instanceI)
+    for (; instanceI >= 0; --instanceI)
     {
         if (ts[instanceI].value() <= startValue)
         {
@@ -780,7 +771,7 @@ Foam::IOobject Foam::fileOperation::findInstance
         }
     }
 
-    // continue searching from here
+    // Continue searching from here
     for (; instanceI >= 0; --instanceI)
     {
         // Shortcut: if actual directory is the timeName we've already tested it
@@ -796,13 +787,10 @@ Foam::IOobject Foam::fileOperation::findInstance
         io.instance() = ts[instanceI].name();
         if (exists(io))
         {
-            if (debug)
-            {
-                InfoInFunction
+            DebugInFunction
                 << "Found exact match for \"" << io.name()
                 << "\" in " << io.instance()/io.local()
                 << endl;
-            }
 
             return io;
         }
@@ -810,11 +798,8 @@ Foam::IOobject Foam::fileOperation::findInstance
         // Check if hit minimum instance
         if (ts[instanceI].name() == stopInstance)
         {
-            if (debug)
-            {
-                InfoInFunction
+            DebugInFunction
                 << "Hit stopInstance " << stopInstance << endl;
-            }
 
             if
             (
@@ -845,27 +830,30 @@ Foam::IOobject Foam::fileOperation::findInstance
         }
     }
 
-    // times() usually already includes the constant() so would have been
-    // checked above. Re-test if
-    // - times() is empty. Sometimes this can happen (e.g. decomposePar with
-    //   collated)
-    // - times()[0] is not constant
-    if (!ts.size() || ts[0].name() != time.constant())
-    {
-        // Note. This needs to be a hard-coded constant, rather than the
-        // constant function of the time, because the latter points to
-        // the case constant directory in parallel cases
+    // Times usually already includes 'constant' so would have been checked
+    // above.
+    // However, re-test under these conditions:
+    // - Times is empty.
+    //   Sometimes this can happen (eg, decomposePar with collated)
+    // - Times[0] is not constant
+    // - The startValue is negative (eg, kivaTest).
+    //   This plays havoc with the reverse search, causing it to miss 'constant'
 
+    if
+    (
+        ts.empty()
+     || ts.first().name() != time.constant()
+     || startValue < 0
+    )
+    {
         io.instance() = time.constant();
         if (exists(io))
         {
-            if (debug)
-            {
-                InfoInFunction
+            DebugInFunction
                 << "Found constant match for \"" << io.name()
                 << "\" in " << io.instance()/io.local()
                 << endl;
-            }
+
             return io;
         }
     }

tutorials/combustion/XiEngineFoam/kivaTest/Allrun-parallel

@@ -0,0 +1,13 @@
+#!/bin/sh
+cd ${0%/*} || exit 1                        # Run from this directory
+. $WM_PROJECT_DIR/bin/tools/RunFunctions    # Tutorial run functions
+
+runApplication kivaToFoam -file otape17
+
+runApplication decomposePar
+
+runParallel $(getApplication)
+
+runApplication reconstructPar
+
+#------------------------------------------------------------------------------

tutorials/combustion/XiEngineFoam/kivaTest/system/decomposeParDict

@@ -0,0 +1,27 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v1812                                 |
+|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      decomposeParDict;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+numberOfSubdomains  4;
+
+method  hierarchical;
+
+coeffs
+{
+    n       (2 2 1);
+}
+
+
+// ************************************************************************* //