1 files changed, 78 insertions, 0 deletions
diff --git a/unittest/test_phi0.c b/unittest/test_phi0.c
new file mode 100644
index 0000000..8063843
--- /dev/null
+++ b/unittest/test_phi0.c
@@ -0,0 +1,78 @@
+/*
+  FILE...: test_phi0.c
+  AUTHOR.: Matthew C. Valenti, Rohit Iyer Seshadri, David Rowe, Don Reid
+  CREATED: Sep 2018
+
+  Compare new generated phi0 function to what was originally in mpdecode_core.c
+*/
+
+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "phi0.h"
+
+
+/* Original Phi function */
+static float phi0_orig( float x ) {
+  float z;
+
+  if (x>10)
+    return( 0 );
+  else if (x< 9.08e-5 )
+    return( 10 );
+  else if (x > 9)
+    return( 1.6881e-4 );
+  /* return( 1.4970e-004 ); */
+  else if (x > 8)
+    return( 4.5887e-4 );
+  /* return( 4.0694e-004 ); */
+  else if (x > 7)
+    return( 1.2473e-3 );
+  /* return( 1.1062e-003 ); */
+  else if (x > 6)
+    return( 3.3906e-3 );
+  /* return( 3.0069e-003 ); */
+  else if (x > 5)
+    return( 9.2168e-3 );
+  /* return( 8.1736e-003 ); */
+  else {
+    z = (float) exp(x);
+    return( (float) log( (z+1)/(z-1) ) ); 
+  }
+}
+
+////////////////////////////////////////////////////
+// Main
+int main(void) {
+
+    float xf;
+    float error;
+    int errsum = 0;
+    int errsum2 = 0;
+    int errcnt = 0;
+
+    for (xf=10.5f; xf>5e-5f; xf = xf * 0.9) {
+
+        float orig = phi0_orig(xf);
+        float new  = phi0(xf);
+
+        error = new - orig;
+        printf("%10.4f: %10.6f - %10.6f = %10.6f", xf, new, orig, error);
+        if ((error >= 0.001) && (error >= (orig * 0.1))) printf(" ****");
+        printf("\n");
+
+        errsum += error;
+        errsum2 += error * error;
+        errcnt ++;
+
+    }
+
+    printf("Net error %f\n", (double)errsum);
+    printf("avg error %f\n", (double)errsum/errcnt);
+    printf("rms error %f\n", (double)sqrt(errsum2/errcnt));
+
+    return(0);
+}
+
+/* vi:set ts=4 et sts=4: */