Changes in / [c31dcdb1:8e7044c] in sasview

File:

• src/sas/sascalc/calculator/c_extensions/libfunc.c (modified) (7 diffs)

src/sas/sascalc/calculator/c_extensions/libfunc.c

@@ -87 +87 @@
 }
 
-/*
+
 double gamln(double xx) {
 
@@ -103 +103 @@
     return -tmp+log(2.5066282746310005*ser/x);
 }
-*/
+
 // calculate magnetic sld and return total sld
 // bn : contrast (not just sld of the layer)
@@ -236 +236 @@
 
 /**
-Wojtek's comment Mar 22 2016: The remaing code can mostly likely be deleated
-Keeping it in order to check if it is not breaking anything
+   Implements eq 6.2.5 (small gamma) of Numerical Recipes in C, essentially
+   the incomplete gamma function multiplied by the gamma function.
+   Required for implementation of fast error function (erf)
 **/
 
@@ -249 +250 @@
   float sum,del,ap;
 
-  *gln = lgamma(a);
+  *gln = gamln(a);
   if(x <= 0.0) {
     if (x < 0.0) printf("Error: x less than 0 in routine gser");
@@ -279 +280 @@
    representation
 **/
+
 void gcf(float *gammcf, float a, float x, float *gln) {
   int i;
   float an,b,c,d,del,h;
 
-  *gln = lgamma(a);
+  *gln = gamln(a);
   b = x+1.0-a;
   c = 1.0/FPMIN;
@@ -305 +307 @@
 }
 
+
 /**
    Represents incomplete error function, P(a,x)
@@ -319 +322 @@
   }
 }
+
 /**
     Implementation of the error function, erf(x)
 **/
+
 float erff(float x) {
   return x < 0.0 ? -gammp(0.5,x*x) : gammp(0.5,x*x);
 }
+