ENH: cachedRandom - added 'shuffle' function to shuffle list inplace

BUG: cachedRandom - updated how generator is (re)initialied

src/OpenFOAM/primitives/random/cachedRandom/cachedRandom.C

@@ -66,19 +66,20 @@ Foam::cachedRandom::cachedRandom(const label seed, const label count)
         seed_ = seed;
     }
 
+    // Initialise samples
+    osRandomSeed(seed_);
+
     // Samples will be cached if count > 0
     if (count > 0)
     {
         samples_.setSize(count);
-        sampleI_ = 0;
-    }
-
-    // Initialise samples
-    osRandomSeed(seed_);
         forAll(samples_, i)
         {
             samples_[i] = osRandomDouble();
         }
+
+        sampleI_ = 0;
+    }
 }
 
 
@@ -90,24 +91,29 @@ Foam::cachedRandom::cachedRandom(const cachedRandom& cr, const bool reset)
     hasGaussSample_(cr.hasGaussSample_),
     gaussSample_(cr.gaussSample_)
 {
+    //if (sampleI_ == -1)
+    //{
+    //    WarningInFunction
+    //        << "Copy constructor called, but samples not being cached. "
+    //        << "This may lead to non-repeatable behaviour" << endl;
+    //
+    //}
+
     if (reset)
     {
         hasGaussSample_ = false;
         gaussSample_ = 0;
-    }
-    if (sampleI_ == -1)
-    {
-        WarningInFunction
-            << "Copy constructor called, but samples not being cached. "
-            << "This may lead to non-repeatable behaviour" << endl;
 
-        osRandomSeed(seed_);
-    }
-
-    if (reset && samples_.size())
+        if (samples_.size())
         {
             sampleI_ = 0;
         }
+        else
+        {
+            // Re-initialise the samples
+            osRandomSeed(seed_);
+        }
+    }
 }
 
 

src/OpenFOAM/primitives/random/cachedRandom/cachedRandom.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -143,6 +143,10 @@ public:
                 template<class Type>
                 void randomise01(Type& value);
 
+                //- Shuffle the values in the list
+                template<class Type>
+                void shuffle(UList<Type>& values);
+
 
             // Global random numbers - consistent across all processors
 
@@ -224,7 +228,7 @@ label cachedRandom::globalPosition<label>(const label& start, const label& end);
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 #ifdef NoRepository
-    #include "cachedRandomTemplates.C"
+#   include "cachedRandomTemplates.C"
 #endif
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

src/OpenFOAM/primitives/random/cachedRandom/cachedRandomTemplates.C

@@ -75,6 +75,23 @@ void Foam::cachedRandom::randomise01(Type& value)
 }
 
 
+template<class Type>
+void Foam::cachedRandom::shuffle(UList<Type>& values)
+{
+    const label nSample = values.size();
+    label posI = nSample - 1;
+
+    for (label i = 1; i < nSample; i++)
+    {
+        label j = position<label>(0, posI);
+        Type t = values[j];
+        values[j] = values[posI];
+        values[posI] = t;
+        posI--;
+    }
+}
+
+
 template<class Type>
 Type Foam::cachedRandom::globalSample01()
 {