Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

ID 767251
Date 11/07/2023
Public

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Document Table of Contents

IEEE_NEXT_DOWN

Elemental Module Intrinsic Function (Generic): Returns the next lower adjacent machine number. This is equivalent to the IEEE nextDown operation.

Module

USE, INTRINSIC :: IEEE_ARITHMETIC

result = IEEE_NEXT_DOWN (x)

x

(Input) Must be of type REAL.

Results

The result type and kind are the same as x. The value of the result is the greatest value that compares less than x - except when x has the value NaN, the result is NaN, and when x has the value - ∞ , the result is - ∞ . If x is a signaling NaN, IEEE_INVALID signals; otherwise, no exception is signaled.

This is the nextDown operation as specified in the ISO/IEC/IEEE 60559:2011 standard.

Example

The value of IEEE_NEXT_DOWN(+0.0) is the negative subnormal number with the least magnitude if the value if IEEE_SUPPORT_SUBNORMAL (0.0) is .TRUE..