Doxygen Source Code Documentation
cdf_54.c File Reference
#include "cdflib.h"Go to the source code of this file.
Functions | |
| double | erfc1 (int *ind, double *x) |
Function Documentation
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Definition at line 2 of file cdf_54.c. References a, c, erfc1(), exparg(), ind, p, q, r, and top. Referenced by basym(), erfc1(), grat1(), and gratio().
00011 {
00012 static double c = .564189583547756e0;
00013 static double a[5] = {
00014 .771058495001320e-04,-.133733772997339e-02,.323076579225834e-01,
00015 .479137145607681e-01,.128379167095513e+00
00016 };
00017 static double b[3] = {
00018 .301048631703895e-02,.538971687740286e-01,.375795757275549e+00
00019 };
00020 static double p[8] = {
00021 -1.36864857382717e-07,5.64195517478974e-01,7.21175825088309e+00,
00022 4.31622272220567e+01,1.52989285046940e+02,3.39320816734344e+02,
00023 4.51918953711873e+02,3.00459261020162e+02
00024 };
00025 static double q[8] = {
00026 1.00000000000000e+00,1.27827273196294e+01,7.70001529352295e+01,
00027 2.77585444743988e+02,6.38980264465631e+02,9.31354094850610e+02,
00028 7.90950925327898e+02,3.00459260956983e+02
00029 };
00030 static double r[5] = {
00031 2.10144126479064e+00,2.62370141675169e+01,2.13688200555087e+01,
00032 4.65807828718470e+00,2.82094791773523e-01
00033 };
00034 static double s[4] = {
00035 9.41537750555460e+01,1.87114811799590e+02,9.90191814623914e+01,
00036 1.80124575948747e+01
00037 };
00038 static int K1 = 1;
00039 static double erfc1,ax,bot,e,t,top,w;
00040 /*
00041 ..
00042 .. Executable Statements ..
00043 */
00044 /*
00045 ABS(X) .LE. 0.5
00046 */
00047 ax = fabs(*x);
00048 if(ax > 0.5e0) goto S10;
00049 t = *x**x;
00050 top = (((a[0]*t+a[1])*t+a[2])*t+a[3])*t+a[4]+1.0e0;
00051 bot = ((b[0]*t+b[1])*t+b[2])*t+1.0e0;
00052 erfc1 = 0.5e0+(0.5e0-*x*(top/bot));
00053 if(*ind != 0) erfc1 = exp(t)*erfc1;
00054 return erfc1;
00055 S10:
00056 /*
00057 0.5 .LT. ABS(X) .LE. 4
00058 */
00059 if(ax > 4.0e0) goto S20;
00060 top = ((((((p[0]*ax+p[1])*ax+p[2])*ax+p[3])*ax+p[4])*ax+p[5])*ax+p[6])*ax+p[
00061 7];
00062 bot = ((((((q[0]*ax+q[1])*ax+q[2])*ax+q[3])*ax+q[4])*ax+q[5])*ax+q[6])*ax+q[
00063 7];
00064 erfc1 = top/bot;
00065 goto S40;
00066 S20:
00067 /*
00068 ABS(X) .GT. 4
00069 */
00070 if(*x <= -5.6e0) goto S60;
00071 if(*ind != 0) goto S30;
00072 if(*x > 100.0e0) goto S70;
00073 if(*x**x > -exparg(&K1)) goto S70;
00074 S30:
00075 t = pow(1.0e0/ *x,2.0);
00076 top = (((r[0]*t+r[1])*t+r[2])*t+r[3])*t+r[4];
00077 bot = (((s[0]*t+s[1])*t+s[2])*t+s[3])*t+1.0e0;
00078 erfc1 = (c-t*top/bot)/ax;
00079 S40:
00080 /*
00081 FINAL ASSEMBLY
00082 */
00083 if(*ind == 0) goto S50;
00084 if(*x < 0.0e0) erfc1 = 2.0e0*exp(*x**x)-erfc1;
00085 return erfc1;
00086 S50:
00087 w = *x**x;
00088 t = w;
00089 e = w-t;
00090 erfc1 = (0.5e0+(0.5e0-e))*exp(-t)*erfc1;
00091 if(*x < 0.0e0) erfc1 = 2.0e0-erfc1;
00092 return erfc1;
00093 S60:
00094 /*
00095 LIMIT VALUE FOR LARGE NEGATIVE X
00096 */
00097 erfc1 = 2.0e0;
00098 if(*ind != 0) erfc1 = 2.0e0*exp(*x**x);
00099 return erfc1;
00100 S70:
00101 /*
00102 LIMIT VALUE FOR LARGE POSITIVE X
00103 WHEN IND = 0
00104 */
00105 erfc1 = 0.0e0;
00106 return erfc1;
00107 } /* END */
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