log returns the natural logarithm of its floating
The coefficients are #2705 from Hart & Cheney. (19.38D)
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
;
temp
= ((p3
*zsq
+ p2
)*zsq
+ p1
)*zsq
+ p0
;
temp
= temp
/(((1.0*zsq
+ q2
)*zsq
+ q1
)*zsq
+ q0
);
temp
= temp
*z
+ exp
*log2
;