made randomnumber generators seeded with fixed values

examples/libexampletools/jkqtpappsettingcontroller.cpp

@@ -5,6 +5,8 @@
 
 JKQTPAppSettingController::JKQTPAppSettingController(int &argc, char **argv, bool enableHighDPIIfAVailable)
 {
+    // seed RNG
+    std::srand(123456);
     bool deactivated=false;
     for (int i=0; i<argc; i++) {
         if (QString(argv[i])=="--disablehighdpi") {

lib/jkqtcommon/jkqtpgeometrytools.cpp

@@ -235,9 +235,10 @@ JKQTPAdaptiveFunctionGraphEvaluator::JKQTPAdaptiveFunctionGraphEvaluator(const s
     minSamples(minSamples_),
     maxRefinementDegree(maxRefinementDegree_),
     slopeTolerance(slopeTolerance_),
-    minPixelPerSample(minPixelPerSample_)
+    minPixelPerSample(minPixelPerSample_),
+    rd(), gen{rd()}, dist(0,1)
 {
-
+    gen.seed(12345);
 }
 
 JKQTPAdaptiveFunctionGraphEvaluator::JKQTPAdaptiveFunctionGraphEvaluator(const std::function<QPointF (double)> &fxy_, unsigned int minSamples_, unsigned int maxRefinementDegree_, double slopeTolerance_, double minPixelPerSample_):
@@ -245,9 +246,10 @@ JKQTPAdaptiveFunctionGraphEvaluator::JKQTPAdaptiveFunctionGraphEvaluator(const s
     minSamples(minSamples_),
     maxRefinementDegree(maxRefinementDegree_),
     slopeTolerance(slopeTolerance_),
-    minPixelPerSample(minPixelPerSample_)
+    minPixelPerSample(minPixelPerSample_),
+    rd(), gen{rd()}, dist(0,1)
 {
-
+    gen.seed(12345);
 }
 
 QVector<QPointF> JKQTPAdaptiveFunctionGraphEvaluator::evaluate(double tmin, double tmax) const
@@ -285,7 +287,7 @@ void JKQTPAdaptiveFunctionGraphEvaluator::refine(JKQTPAdaptiveFunctionGraphEvalu
     if (degree>=maxRefinementDegree) return;
     const double ta=a->first;
     const double tb=b->first;
-    const double tmid=ta+(tb-ta)*(0.5 +(static_cast<double>(rand())/static_cast<double>(RAND_MAX)-0.5)/5.0);
+    const double tmid=ta+(tb-ta)*(0.5 +(dist(gen)-0.5)/5.0);
     const QPointF pa=a->second;
     const QPointF pb=b->second;
     const QPointF pmid(fxy(tmid));

lib/jkqtcommon/jkqtpgeometrytools.h

@@ -33,6 +33,7 @@
 #include <forward_list>
 #include <cmath>
 #include <utility>
+#include <random>
 #include <QDebug>
 #include "jkqtcommon/jkqtpmathtools.h"
 #include "jkqtcommon/jkqtpcodestructuring.h"
@@ -105,6 +106,13 @@ protected:
     double slopeTolerance;
     /** \brief create one sample at least every \a minPixelPerSample pixels */
     double minPixelPerSample;
+    /** \brief random number generation: device */
+    mutable std::random_device rd; // random number generators:
+    /** \brief random number generation: egenrator */
+    mutable std::mt19937 gen;
+    /** \brief random number generation: distribution */
+    mutable std::uniform_real_distribution<double> dist;
+
 };