Implementations of sqrtl and logl

Peter Jeremy PeterJeremy at optushome.com.au
Fri Dec 30 10:26:30 PST 2005


On Thu, 2005-Dec-29 14:46:26 -0800, Steve Kargl wrote:
>I have implementations for sqrtl and logl, which can be added
>to libm.  In limited testing on AMD64 , I find
>
>troutmask:kargl[208] ./test_sqrt 
>     float         double        long double
>MRE: 8.953800e-08  1.664855e-16  1.084202e-19
>DDP: 7.05          15.78         18.96
>BDP: 23.41         52.42         63.00
...
>MRE = maximum relative error between a value from my routine and
>      a value computed using GMP/MPFR with 64-bits of precision.

Given that long double has 64 bits of precision, is testing it against
a 64-bit test library adequate?  And what is the accuracy of your test
library?

-- 
Peter Jeremy


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