rsys

commit e0b1b8b3cfc62bedfa09e9143bf1292ad0f6bcf7
parent 619f8395744f7a84f90ed9e68f3f3cd0bb812a84
Author: vaplv <vaplv@free.fr>
Date:   Fri,  3 Apr 2015 11:12:42 +0200

Add and test the sin2cos and cos2sin functions

Diffstat:
M
src/math.h
 | 
12
++++++++++++
M
src/test_math.c
 | 
12
++++++++++++

2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/src/math.h b/src/math.h
@@ -84,4 +84,16 @@ eq_epsf(const float a, const float b, const float eps)
   return absf(a - b) <= eps;
 }
 
+static FINLINE double
+sin2cos(const double d)
+{
+  return sqrt(MMAX(0.0, 1.0 - d*d));
+}
+
+static FINLINE double
+cos2sin(const double d)
+{
+  return sin2cos(d);
+}
+
 #endif /* MATH_H */
diff --git a/src/test_math.c b/src/test_math.c
@@ -19,6 +19,7 @@ int
 main(int argc, char** argv)
 {
   float f, g;
+  int i;
   (void)argc, (void)argv;
 
   f = -3.14159f; CHECK(absf(f),-f);
@@ -86,6 +87,17 @@ main(int argc, char** argv)
   CHECK(eq_eps(MRAD2DEG(PI*0.75), 135.0, 1.e-8), 1);
   CHECK(eq_eps(MRAD2DEG(MDEG2RAD(70.0)), 70.0, 1.e-8), 1);
 
+  FOR_EACH(i, 0, 16) {
+    double d, c, s, tmp;
+    d = ((float)rand() / (float)RAND_MAX) * PI;
+    c = cos(d);
+    s = sin(d);
+    tmp = cos2sin(c);
+    CHECK(eq_eps(s, tmp, 1.0e-8) || eq_eps(s, -tmp, 1.0e-8), 1);
+    tmp = sin2cos(s);
+    CHECK(eq_eps(c, tmp, 1.0e-8) || eq_eps(c, -tmp, 1.0e-8), 1);
+  }
+
   CHECK(signf(-3.14159f), -1.f);
   CHECK(signf(1.23f), 1.f);
   CHECK(signf(0.f), 1.f);