# NAG Library Routine Document

## 1Purpose

x02alf returns the largest positive floating-point number.

## 2Specification

Fortran Interface
 Function x02alf ( )
 Real (Kind=nag_wp) :: x02alf
#include nagmk26.h
 double x02alf_ ()

## 3Description

x02alf returns the largest positive number in the model of floating-point arithmetic described in the X02 Chapter Introduction. The returned value is equal to $\left(1-{b}^{-p}\right)×{b}^{{e}_{\mathrm{max}}}$, where $b$ is the arithmetic base (see x02bhf) and ${e}_{\mathrm{max}}$ is the maximum exponent (see x02blf) in the model.

None.

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## 8Parallelism and Performance

x02alf is not threaded in any implementation.