log1p - computes with accuracy the natural logarithm of its argument added by one
logp1(x) is the "element-wise" log(1+x) function. y(i,j)=log(1 + x(i,j)) . This function, defined for x > -1, must be used if we want to compute log(1+x) with accuracy for |x| << 1.
format("e",24)
log(1.001)
log1p(0.001)
log(1 + 1.e-7)
log1p(1.e-7)
log(1 + 1.e-20)
log1p(1.e-20)
format("v") //reset default format
log ,
B.P.;