2 log returns the natural logarithm of its floating
5 The coefficients are #2705 from Hart & Cheney. (19.38D)
13 #define log2 0.693147180559945309e0
14 #define ln10o1 .4342944819032518276511
15 #define sqrto2 0.707106781186547524e0
16 #define p0 -.240139179559210510e2
17 #define p1 0.309572928215376501e2
18 #define p2 -.963769093377840513e1
19 #define p3 0.421087371217979714e0
20 #define q0 -.120069589779605255e2
21 #define q1 0.194809660700889731e2
22 #define q2 -.891110902798312337e1
27 double x, z, zsq, temp;
45 temp = ((p3*zsq + p2)*zsq + p1)*zsq + p0;
46 temp = temp/(((zsq + q2)*zsq + q1)*zsq + q0);
47 temp = temp*z + exp*log2;
57 return log(arg) * ln10o1;