The “relative” function EXPRL is useful for accurately computing ex −  1 near x = 0. Computing
ex − 1 using EXP(X) − 1 near x = 0 is subject to large cancellation errors.

Similarly, ALNREL can be used to accurately compute ln(x + 1) near x = 0. Using the routine ALOG to compute ln(x + 1) near x = 0 is subject to large cancellation errors in the computation of 1 + X.

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