Re: [eigen] Eigen SSE denorm modes?

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On 03/08/2012 04:22 PM, Dick Lyon wrote:
Is there a way to control how Eigen deals with denormalized floats?
There are low-level SSE registers to control flushing to zero and such,
but does anyone who how to control them, or what the defaults are?


DAZ and FTZ makes a big speedup on intel machines, since handling denormals is really slow (and often only propagates rounding errors).

You can enabling these modes yourself:
    _mm_setcsr( _mm_getcsr() | (1<<15));  // FTZ
    _mm_setcsr( _mm_getcsr() | (1<<6)); // DAZ

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