logF

Logf is the single-precision floating-point version of the natural logarithm in the C standard library. It computes the natural logarithm, ln(x), of a finite positive float x. The function is declared in math.h and is part of the C99 standard and later; it is also available in C++ via the <cmath> header.

The function signature is float logf(float x). Behavior is defined for different domains: if x > 0, logf returns the finite value ln(x); if x == 0, it returns negative infinity; if x < 0, the result is Not a Number (NaN). If x is NaN, the result is NaN. In some environments, floating-point exceptions may be raised and errno may be set (for example, ERANGE or EDOM) depending on the platform and library implementation. Because of floating-point semantics, exact results can vary slightly between implementations.

Implementation considerations include that logf may be implemented directly in hardware or via software routines, often using internal promotion to higher precision for accuracy before converting back to float. It is designed for single-precision workflows and is typically faster than its double-precision counterpart, log, when working with float data.

Usage contexts include numerical computations, normalizations, log-likelihood calculations, and other algorithms where the natural logarithm of a float is required. For higher precision, equivalent functions exist for double (log) and long double (logl). Related functions include logf, log, logl, and base-10 or base-2 variants such as log10f and log2f.