ENH: histogram: 1) if max is not provided use field max. 2) output count. Fixes #467.

src/functionObjects/field/histogram/histogram.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -45,23 +45,31 @@ void Foam::functionObjects::histogram::writeGraph
 (
     const coordSet& coords,
     const word& fieldName,
-    const scalarField& values
+    const scalarField& normalizedValues,
+    const scalarField& absoluteValues
 ) const
 {
-    const wordList fieldNames(1, fieldName);
-
     fileName outputPath = baseTimeDir();
     mkDir(outputPath);
     OFstream graphFile
     (
-        outputPath/formatterPtr_().getFileName(coords, fieldNames)
+        outputPath
+       /formatterPtr_().getFileName
+        (
+            coords,
+            wordList(1, fieldName)
+        )
     );
 
     Log << "    Writing histogram of " << fieldName
         << " to " << graphFile.name() << endl;
 
-    List<const scalarField*> yPtrs(1);
+    wordList fieldNames(2);
-    yPtrs[0] = &values;
+    fieldNames[0] = fieldName;
+    fieldNames[1] = fieldName + "Count";
+    List<const scalarField*> yPtrs(2);
+    yPtrs[0] = &normalizedValues;
+    yPtrs[1] = &absoluteValues;
     formatterPtr_().write(coords, fieldNames, yPtrs, graphFile);
 }
 
@@ -76,7 +84,9 @@ Foam::functionObjects::histogram::histogram
 )
 :
     fvMeshFunctionObject(name, runTime, dict),
-    writeFile(obr_, name)
+    writeFile(obr_, name),
+    max_(-GREAT),
+    min_(GREAT)
 {
     read(dict);
 }
@@ -96,8 +106,9 @@ bool Foam::functionObjects::histogram::read(const dictionary& dict)
     writeFile::read(dict);
 
     dict.lookup("field") >> fieldName_;
-    dict.lookup("max") >> max_;
+
-    min_ = dict.lookupOrDefault<scalar>("min", 0);
+    max_ = dict.lookupOrDefault<scalar>("max", -GREAT);
+    min_ = dict.lookupOrDefault<scalar>("min", GREAT);
     dict.lookup("nBins") >> nBins_;
 
     word format(dict.lookup("setFormat"));
@@ -149,38 +160,63 @@ bool Foam::functionObjects::histogram::write()
        : obr_.lookupObject<volScalarField>(fieldName_)
     );
 
+
+    scalar histMax = max_;
+    scalar histMin = min_;
+
+    if (max_ == -GREAT)
+    {
+        // Determine current min and max
+        histMax = max(field).value();
+
+        if (min_ == GREAT)
+        {
+            histMin = min(field).value();
+        }
+        Log << "    Determined histogram bounds from field"
+            << " min/max(" << fieldName_ << ") = "
+            << histMin << ' ' << histMax << endl;
+    }
+    else if (min_ == GREAT)
+    {
+        histMin = 0;
+    }
+
     // Calculate the mid-points of bins for the graph axis
     pointField xBin(nBins_);
-    const scalar delta = (max_- min_)/nBins_;
+    const scalar delta = (histMax- histMin)/nBins_;
 
-    scalar x = min_ + 0.5*delta;
+    scalar x = histMin + 0.5*delta;
     forAll(xBin, i)
     {
         xBin[i] = point(x, 0, 0);
         x += delta;
     }
 
-    scalarField data(nBins_, 0);
+    scalarField dataNormalized(nBins_, 0);
+    labelField dataCount(nBins_, 0);
     const scalarField& V = mesh_.V();
 
     forAll(field, celli)
     {
-        const label bini = (field[celli] - min_)/delta;
+        const label bini = (field[celli] - histMin)/delta;
         if (bini >= 0 && bini < nBins_)
         {
-            data[bini] += V[celli];
+            dataNormalized[bini] += V[celli];
+            dataCount[bini]++;
         }
     }
 
-    Pstream::listCombineGather(data, plusEqOp<scalar>());
+    Pstream::listCombineGather(dataNormalized, plusEqOp<scalar>());
+    Pstream::listCombineGather(dataCount, plusEqOp<label>());
 
     if (Pstream::master())
     {
-        const scalar sumData = sum(data);
+        const scalar sumData = sum(dataNormalized);
 
         if (sumData > SMALL)
         {
-            data /= sumData;
+            dataNormalized /= sumData;
 
             const coordSet coords
             (
@@ -190,7 +226,15 @@ bool Foam::functionObjects::histogram::write()
                 mag(xBin)
             );
 
-            writeGraph(coords, fieldName_, data);
+
+            // Convert count field from labelField to scalarField
+            scalarField count(dataCount.size());
+            forAll(count, i)
+            {
+                count[i] = 1.0*dataCount[i];
+            }
+
+            writeGraph(coords, fieldName_, dataNormalized, count);
         }
     }
 

src/functionObjects/field/histogram/histogram.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -53,7 +53,7 @@ Usage
         type         | type name: histogram    | yes         |
         field        | Field to analyse        | yes         |
         nBins        | Number of bins for the histogram | yes|
-        max          | Maximum value sampled   | yes         |
+        max          | Maximum value sampled   | no          | field max
         min          | minimum value sampled   | no          | 0
         setFormat    | Output format           | yes         |
     \endtable
@@ -115,7 +115,8 @@ class histogram
         (
             const coordSet& coords,
             const word& valueName,
-            const scalarField& values
+            const scalarField& normalizedValues,
+            const scalarField& absoluteValues
         ) const;
 
         //- Disallow default bitwise copy construct