#include "cdflib.h"
double erf1(double *x)
/*
-----------------------------------------------------------------------
             EVALUATION OF THE REAL ERROR FUNCTION
-----------------------------------------------------------------------
*/
{
static double c = .564189583547756e0;
static double a[5] = {
    .771058495001320e-04,-.133733772997339e-02,.323076579225834e-01,
    .479137145607681e-01,.128379167095513e+00
};
static double b[3] = {
    .301048631703895e-02,.538971687740286e-01,.375795757275549e+00
};
static double p[8] = {
    -1.36864857382717e-07,5.64195517478974e-01,7.21175825088309e+00,
    4.31622272220567e+01,1.52989285046940e+02,3.39320816734344e+02,
    4.51918953711873e+02,3.00459261020162e+02
};
static double q[8] = {
    1.00000000000000e+00,1.27827273196294e+01,7.70001529352295e+01,
    2.77585444743988e+02,6.38980264465631e+02,9.31354094850610e+02,
    7.90950925327898e+02,3.00459260956983e+02
};
static double r[5] = {
    2.10144126479064e+00,2.62370141675169e+01,2.13688200555087e+01,
    4.65807828718470e+00,2.82094791773523e-01
};
static double s[4] = {
    9.41537750555460e+01,1.87114811799590e+02,9.90191814623914e+01,
    1.80124575948747e+01
};
static double erf1,ax,bot,t,top,x2;
/*
     ..
     .. Executable Statements ..
*/
    ax = fabs(*x);
    if(ax > 0.5e0) goto S10;
    t = *x**x;
    top = (((a[0]*t+a[1])*t+a[2])*t+a[3])*t+a[4]+1.0e0;
    bot = ((b[0]*t+b[1])*t+b[2])*t+1.0e0;
    erf1 = *x*(top/bot);
    return erf1;
S10:
    if(ax > 4.0e0) goto S20;
    top = ((((((p[0]*ax+p[1])*ax+p[2])*ax+p[3])*ax+p[4])*ax+p[5])*ax+p[6])*ax+p[
      7];
    bot = ((((((q[0]*ax+q[1])*ax+q[2])*ax+q[3])*ax+q[4])*ax+q[5])*ax+q[6])*ax+q[
      7];
    erf1 = 0.5e0+(0.5e0-exp(-(*x**x))*top/bot);
    if(*x < 0.0e0) erf1 = -erf1;
    return erf1;
S20:
    if(ax >= 5.8e0) goto S30;
    x2 = *x**x;
    t = 1.0e0/x2;
    top = (((r[0]*t+r[1])*t+r[2])*t+r[3])*t+r[4];
    bot = (((s[0]*t+s[1])*t+s[2])*t+s[3])*t+1.0e0;
    erf1 = (c-top/(x2*bot))/ax;
    erf1 = 0.5e0+(0.5e0-exp(-x2)*erf1);
    if(*x < 0.0e0) erf1 = -erf1;
    return erf1;
S30:
    erf1 = fifdsign(1.0e0,*x);
    return erf1;
} /* END */