Python speed vs csharp

Terry Reedy tjreedy at udel.edu
Fri Aug 1 02:51:16 CEST 2003


"David M. Cooke" <cookedm+news at physics.mcmaster.ca> wrote in message
news:qnkn0eutndk.fsf at arbutus.physics.mcmaster.ca...
> At some point, Mike <mike at nospam.com> wrote:
> > Here's the chunk of code that I'm spending most of my time
executing:
> >
> > # Rational approximation for erfc(x) (Abramowitz & Stegun, Sec.
7.1.26)
> > # Fifth order approximation. |error| <= 1.5e-7 for all x
> > #
> > def erfc( x ):
> >    p  =  0.3275911
> >    a1 =  0.254829592
> >    a2 = -0.284496736
> >    a3 =  1.421413741
> >    a4 = -1.453152027
> >    a5 =  1.061405429
> >
> >    t = 1.0 / (1.0 + p*float(x))
> >    erfcx = ( (a1 + (a2 + (a3 +
> >              (a4 + a5*t)*t)*t)*t)*t ) * math.exp(-(x**2))
> >    return erfcx

Does inlining the constants give any speedup?  or is local lookup so
fast that it does not matter?

TJR






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