Added our tweaked version of NAS benchmarks.

[simgrid.git] / examples / smpi / NAS / common / randdp.c

diff --git a/examples/smpi/NAS/common/randdp.c b/examples/smpi/NAS/common/randdp.c
new file mode 100644 (file)
index 0000000..6766247
--- /dev/null
+++ b/examples/smpi/NAS/common/randdp.c
@@ -0,0 +1,64 @@
+//---------------------------------------------------------------------
+//   This function is C verson of random number generator randdp.f 
+//---------------------------------------------------------------------
+
+double randlc(X, A)
+double *X;
+double *A;
+{
+      static int        KS=0;
+      static double    R23, R46, T23, T46;
+      double           T1, T2, T3, T4;
+      double           A1;
+      double           A2;
+      double           X1;
+      double           X2;
+      double           Z;
+      int              i, j;
+
+      if (KS == 0) 
+      {
+        R23 = 1.0;
+        R46 = 1.0;
+        T23 = 1.0;
+        T46 = 1.0;
+    
+        for (i=1; i<=23; i++)
+        {
+          R23 = 0.50 * R23;
+          T23 = 2.0 * T23;
+        }
+        for (i=1; i<=46; i++)
+        {
+          R46 = 0.50 * R46;
+          T46 = 2.0 * T46;
+        }
+        KS = 1;
+      }
+
+/*  Break A into two parts such that A = 2^23 * A1 + A2 and set X = N.  */
+
+      T1 = R23 * *A;
+      j  = T1;
+      A1 = j;
+      A2 = *A - T23 * A1;
+
+/*  Break X into two parts such that X = 2^23 * X1 + X2, compute
+    Z = A1 * X2 + A2 * X1  (mod 2^23), and then
+    X = 2^23 * Z + A2 * X2  (mod 2^46).                            */
+
+      T1 = R23 * *X;
+      j  = T1;
+      X1 = j;
+      X2 = *X - T23 * X1;
+      T1 = A1 * X2 + A2 * X1;
+      
+      j  = R23 * T1;
+      T2 = j;
+      Z = T1 - T23 * T2;
+      T3 = T23 * Z + A2 * X2;
+      j  = R46 * T3;
+      T4 = j;
+      *X = T3 - T46 * T4;
+      return(R46 * *X);
+}