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jimdempseyatthecove

Black Belt

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04-05-2016
08:16 AM

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/Qprec-sqrt documentation

When issuing ifort /? to list the options we see:

*/Qprec-sqrt[-]
determine if certain square root optimizations are enabled*

Shouldn't this enable (full) precision, or disable (fast) precision of square root?

Jim Dempsey

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Steven_L_Intel1

Employee

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04-05-2016
08:23 AM

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-no-prec-sqrt |
The compiler uses a faster but less precise implementation of square root. However, the default is -prec-sqrt or /Qprec-sqrt if any of the following options are specified: /Od, /fltconsistency, or /Qprec on Windows* systems; -O0 , -fltconsistency, or -mp1 on Linux* and OS X* systems. |

This option improves precision of square root implementations. It has a slight impact on speed.

This option inhibits any optimizations that can adversely affect the precision of a square root computation. The result is fully precise square root implementations, with some loss of performance.

For more complete information about compiler optimizations, see our Optimization Notice.