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

pc, Qpc

Enables control of floating-point significand precision.

Syntax

Linux:

-pcn

Windows:

/Qpcn

Arguments

n

Is the floating-point significand precision. Possible values are:

32

Rounds the significand to 24 bits (single precision).

64

Rounds the significand to 53 bits (double precision).

80

Rounds the significand to 64 bits (extended precision).

Default

-pc80
or /Qpc64

On Linux* systems, the floating-point significand is rounded to 64 bits.

On Windows* systems, the floating-point significand is rounded to 53 bits.

Description

This option enables control of floating-point significand precision.

Some floating-point algorithms are sensitive to the accuracy of the significand, or fractional part of the floating-point value. For example, iterative operations like division and finding the square root can run faster if you lower the precision with this option.

Note that a change of the default precision control or rounding mode, for example, by using the [Q]pc32 option or by user intervention, may affect the results returned by some of the mathematical functions.

IDE Equivalent

None

Alternate Options

None