Returns information describing the computer’s floating-point arithmetic.

The requested value is returned. If n is out of range, then NaN is returned.

The function imsl_f_machine returns information describing the computer’s floating-point arithmetic. This can be used to make programs machine independent. In addition, some of the functions are also important in setting missing values (see below).

Assume that float numbers are represented in Nf-digit, base B form as

where σ is the sign, 0 ≤ xk < B for k = 1, 2, …, Nf, and

Note that B = imsl_i_machine(6),  Nf = imsl_i_machine(7),

and

The ANSI/IEEE Std 754-1985 standard for binary arithmetic uses NaN (not a number) as the result of various otherwise illegal operations, such as computing 0/0. On computers that do not support NaN, a value larger than imsl_d_machine(2) is returned for imsl_f_machine(6). On computers that do not have a special representation for infinity, imsl_f_machine(2) returns the same value as imsl_f_machine(7).

The function imsl_f_machine is defined by the following table:

The function imsl_d_machine retrieves machine constants which define the computer’s double arithmetic. Note that for double B = imsl_i_machine(6), Nd = imsl_i_machine(10),

and

Missing values in IMSL functions are always indicated by NaN (Not a Number). This is imsl_f_machine(6) in single precision and imsl_d_machine(6) in double. There is no missing-value indicator for integers. Users will almost always have to convert from their missing value indicators to NaN.

This example prints all eight values returned by imsl_f_machine and by imsl_d_machine on a machine with IEEE arithmetic.