This option lets you specify a level of accuracy (precision) that the
compiler should use when determining which math library functions to use.
This option can be used to improve run-time performance if reduced accuracy
is sufficient for the application, or it can be used to increase the accuracy
of math library functions selected by the compiler.
In general, using a lower precision can improve run-time performance and
using a higher precision may reduce run-time performance.
If you need to define the accuracy for a math function of a certain
precision, specify the function name of the precision that you need. For
example, if you want double precision, you can specify :sin; if you want single
precision, you can specify :sinf, as in
If you do not specify any function names, then the setting applies to all
functions (and to all precisions). However, as soon as you specify an
individual function name, the setting applies only to the function of
corresponding precision. So, for example, sinf applies only to the
single-precision sine function, sin applies only to the double-precision sine
function, sinl applies only to the extended-precision sine function, etc.
There are three options you can use to express the maximum relative error.
They are as follows:
If more than one of these options are specified, the default value for the
maximum relative error is determined by the last one specified on the command
If none of the above options are specified, the default values for the
maximum relative error are determined by the setting of the following options:
Many routines in libraries LIBM (Math Library) and SVML
(Short Vector Math Library) are more highly optimized for Intel®
microprocessors than for non-Intel microprocessors.
Product and Performance Information
Notice revision #20201201