added a thread-safe and cross-plateform random number generator

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@3373 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/tests/general/Makefile

@@ -7,14 +7,17 @@ RS_TOP_DIR = ../..
 include $(RS_TOP_DIR)/tests/scripts/config.mk
 ###############################################################
 
-TESTOBJ  = netsetup_test.o
-TESTS  = netsetup_test
+TESTOBJ  = netsetup_test.o random_test.o
+TESTS  = netsetup_test random_test
 
 all: tests
 
 netsetup_test: netsetup_test.o 
 	$(CC) $(CFLAGS) -o netsetup_test netsetup_test.o $(LIBS)
 
+random_test: random_test.o 
+	$(CC) $(CFLAGS) -o random_test random_test.o $(LIBS)
+
 ###############################################################
 include $(RS_TOP_DIR)/tests/scripts/rules.mk
 ###############################################################

libretroshare/src/tests/general/random_test.cc

@@ -0,0 +1,161 @@
+#ifdef LINUX
+#include <fenv.h>
+#endif
+#include <iostream>
+#include <vector>
+#include <stdlib.h>
+#include <math.h>
+#include "util/utest.h"
+#include "util/rsrandom.h"
+
+INITTEST();
+typedef double (* Ifctn)( double t);
+/* Numerical integration method */
+double Simpson3_8( Ifctn f, double a, double b, int N)
+{
+    int j;
+    double l1;
+    double h = (b-a)/N;
+    double h1 = h/3.0;
+    double sum = f(a) + f(b);
+ 
+    for (j=3*N-1; j>0; j--) {
+        l1 = (j%3)? 3.0 : 2.0;
+        sum += l1*f(a+h1*j) ;
+    }
+    return h*sum/8.0;
+}
+ 
+#define A 12
+double Gamma_Spouge( double z )
+{
+    int k;
+    static double cspace[A];
+    static double *coefs = NULL;
+    double accum;
+    double a = A;
+ 
+    if (!coefs) {
+        double k1_factrl = 1.0;
+        coefs = cspace;
+        coefs[0] = sqrt(2.0*M_PI);
+        for(k=1; k<A; k++) {
+            coefs[k] = exp(a-k) * pow(a-k,k-0.5) / k1_factrl;
+            k1_factrl *= -k;
+        }
+    }
+ 
+    accum = coefs[0];
+    for (k=1; k<A; k++) {
+        accum += coefs[k]/(z+k);
+    }
+    accum *= exp(-(z+a)) * pow(z+a, z+0.5);
+    return accum/z;
+}
+ 
+double aa1;
+double f0( double t)
+{
+	return  pow(t, aa1)*exp(-t); 
+}
+ 
+double GammaIncomplete_Q( double a, double x)
+{
+    double y, h = 1.5e-2;  /* approximate integration step size */
+ 
+    /* this cuts off the tail of the integration to speed things up */
+    y = aa1 = a-1;
+    while((f0(y) * (x-y) > 2.0e-8) && (y < x))   y += .4;
+    if (y>x) y=x;
+ 
+    return 1.0 - Simpson3_8( &f0, 0, y, std::max(5,(int)(y/h)))/Gamma_Spouge(a);
+}
+
+double chi2Probability( int dof, double distance)
+{
+    return GammaIncomplete_Q( 0.5*dof, 0.5*distance);
+}
+
+class myThread: public RsThread
+{
+	public:
+		myThread()
+		{
+			_finished = false ;
+		}
+		virtual void run()
+		{
+			// test that random numbers are regularly disposed
+			//
+			int N = 500 ;
+			int B = 8 ;
+
+			std::vector<int> buckets(B,0) ;
+
+			for(int i=0;i<N;++i)
+			{
+				float f = RSRandom::random_f32() ;
+				int b = (int)floor(f*B*0.99999999) ;
+				++buckets[b] ;
+			}
+
+			// Chi2 test
+			//
+			float chi2 = 0.0f ;
+			float expected = 1.0/(float)B ;
+
+			for(int k=0;k<B;++k)
+				chi2 += pow( buckets[k]/float(N) - expected,2)/expected ;
+
+			double chi2prob = chi2Probability(B-1,chi2) ;
+			double significance = 0.05 ;
+
+			std::cerr << "Compariing chi2 uniform distance " << chi2 << " to chi2 probability " << chi2prob ;
+
+			if(chi2prob > significance)
+				std::cerr << ": passed" << std::endl ;
+			else
+				std::cerr << ": failed" << std::endl ;
+
+			_finished = true ;
+		}
+
+		bool finished() const { return _finished ; }
+	private:
+		bool _finished ;
+};
+
+
+int main(int argc, char **argv)
+{
+#ifdef LINUX
+	feenableexcept(FE_INVALID) ;
+	feenableexcept(FE_DIVBYZERO) ;
+#endif
+	int nt = 10 ;	// number of threads.
+	std::vector<myThread *> threads(nt,(myThread*)NULL) ;
+
+	for(int i=0;i<nt;++i)
+	{
+		threads[i] = new myThread ;
+		threads[i]->start() ;
+	}
+
+	while(true)
+	{
+		bool finished = true ;
+
+		for(int i=0;i<nt;++i)
+			if(!threads[i]->finished())
+				finished = false ;
+
+		if(finished)
+			break ;
+	}
+	for(int i=0;i<nt;++i)
+		delete threads[i] ;
+
+	FINALREPORT("random_test");
+	exit(TESTRESULT());
+}
+