#include "cdflib.h" double rlog1(double *x) /* ----------------------------------------------------------------------- EVALUATION OF THE FUNCTION X - LN(1 + X) ----------------------------------------------------------------------- */ { static double a = .566749439387324e-01; static double b = .456512608815524e-01; static double p0 = .333333333333333e+00; static double p1 = -.224696413112536e+00; static double p2 = .620886815375787e-02; static double q1 = -.127408923933623e+01; static double q2 = .354508718369557e+00; static double rlog1,h,r,t,w,w1; /* .. .. Executable Statements .. */ if(*x < -0.39e0 || *x > 0.57e0) goto S40; if(*x < -0.18e0) goto S10; if(*x > 0.18e0) goto S20; /* ARGUMENT REDUCTION */ h = *x; w1 = 0.0e0; goto S30; S10: h = *x+0.3e0; h /= 0.7e0; w1 = a-h*0.3e0; goto S30; S20: h = 0.75e0**x-0.25e0; w1 = b+h/3.0e0; S30: /* SERIES EXPANSION */ r = h/(h+2.0e0); t = r*r; w = ((p2*t+p1)*t+p0)/((q2*t+q1)*t+1.0e0); rlog1 = 2.0e0*t*(1.0e0/(1.0e0-r)-r*w)+w1; return rlog1; S40: w = *x+0.5e0+0.5e0; rlog1 = *x-log(w); return rlog1; } /* END */