Visible to Intel only — GUID: GUID-0A4F4F35-1495-4154-8AD5-238E8C68CE9B
Visible to Intel only — GUID: GUID-0A4F4F35-1495-4154-8AD5-238E8C68CE9B
fast-transcendentals, Qfast-transcendentals
Enables the compiler to replace calls to transcendental functions with faster but less precise implementations. This feature is only available for ifort.
Syntax
Linux: |
-fast-transcendentals -no-fast-transcendentals |
Windows: |
/Qfast-transcendentals /Qfast-transcendentals- |
Arguments
None
Default
depends on the setting of -fp-model (Linux*) or /fp (Windows*) |
If you do not specify option -[no-]fast-transcendentals or option /Qfast-transcendentals[-]:
|
Description
This option enables the compiler to replace calls to transcendental functions with implementations that may be faster but less precise.
It allows the compiler to perform certain optimizations on transcendental functions, such as replacing individual calls to sine in a loop with a single call to a less precise vectorized sine library routine. These optimizations can cause numerical differences that would not otherwise exist if you are also compiling with a value-safe option such as -fp-model precise (Linux*) or /fp:precise (Windows).
For example, you may get different results if you specify option O0 versus option O2, or you may get different results from calling the same function with the same input at different points in your program. If these kinds of numerical differences are problematic, consider using option -fimf-use-svml (Linux*) or /Qimf-use-svml (Windows) as an alternative. When used with a value-safe option such as -fp-model precise or /fp:precise, option -fimf-use-svml or /Qimf-use-svml provides many of the positive performance benefits of [Q]fast-transcendentals without negatively affecting numeric consistency. For more details, see the description of option -fimf-use-svml and /Qimf-use-svml.
This option does not affect explicit Short Vector Math Library (SVML) intrinsics. It only affects scalar calls to the standard math library routines.
You cannot use option -fast-transcendentals with option -fp-model strict and you cannot use option /Qfast-transcendentals with option /fp:strict.
This option determines the setting for the maximum allowable relative error for math library function results (max-error) if none of the following options are specified:
-fimf-accuracy-bits (Linux*) or /Qimf-accuracy-bits (Windows*)
-fimf-max-error (Linux) or /Qimf-max-error (Windows)
-fimf-precision (Linux) or /Qimf-precision (Windows)
This option enables extra optimization that only applies to Intel® processors.
Product and Performance Information |
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Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex. Notice revision #20201201 |
IDE Equivalent
Alternate Options
None