/*	log returns the natural logarithm of its floating	point argument.	The coefficients are #2705 from Hart & Cheney. (19.38D)	It calls frexp.*/#include <errno.h>#include <math.h>int	errno;double	frexp();static double	log2	= 0.693147180559945309e0;static double	ln10	= 2.302585092994045684;static double	sqrto2	= 0.707106781186547524e0;static double	p0	= -.240139179559210510e2;static double	p1	= 0.309572928215376501e2;static double	p2	= -.963769093368686593e1;static double	p3	= 0.421087371217979714e0;static double	q0	= -.120069589779605255e2;static double	q1	= 0.194809660700889731e2;static double	q2	= -.891110902798312337e1;doublelog(arg)double arg;{	double x,z, zsq, temp;	int exp;	if(arg <= 0.) {		errno = EDOM;		return(-HUGE);	}	x = frexp(arg,&exp);	while(x<0.5) {		x = x*2;		exp = exp-1;	}	if(x<sqrto2) {		x = 2*x;		exp = exp-1;	}	z = (x-1)/(x+1);	zsq = z*z;	temp = ((p3*zsq + p2)*zsq + p1)*zsq + p0;	temp = temp/(((1.0*zsq + q2)*zsq + q1)*zsq + q0);	temp = temp*z + exp*log2;	return(temp);}doublelog10(arg)double arg;{	return(log(arg)/ln10);}