log1p

Arguments

x

real scalar, vector or matrix

y

real scalar, vector or matrix

Description

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.

Examples

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

See Also

• log — logarithme naturel

Authors

B.P.