Simplify bsincgen's Kaiser function

1 files changed, 3 insertions, 8 deletions

diff --git a/utils/bsincgen.c b/utils/bsincgen.c
index 138f7a68..e4683ded 100644
--- a/utils/bsincgen.c
+++ b/utils/bsincgen.c
@@ -51,7 +51,7 @@
 

 #define BSINC_REJECTION (60.0)

 #define BSINC_POINTS_MIN (12)

-#define BSINC_ORDER (11)

+#define BSINC_ORDER (BSINC_POINTS_MIN - 1)

 

 static double MinDouble(double a, double b)

 { return (a <= b) ? a : b; }

@@ -98,14 +98,9 @@ static double BesselI_0(const double x)
  */

 static double Kaiser(const double b, const double k)

 {

-    double k2;

-

-    if((k < -1.0) || (k > 1.0))

+    if(!(k >= -1.0 && k <= 1.0))

         return 0.0;

-

-    k2 = MaxDouble(1.0 - (k * k), 0.0);

-

-    return BesselI_0(b * sqrt(k2)) / BesselI_0(b);

+    return BesselI_0(b * sqrt(1.0 - k*k)) / BesselI_0(b);

 }

 

 /* NOTE: Calculates the transition width of the Kaiser window.  Rejection is