OK, I've worked out how to do this with MA. I mask the Numeric array input to MA.exp() using MA.masked_outside( ... ,-700, 700) then convert the result back to a Numeric array using MA.filled( ..., 0.0) then continue as normal. I'm still interested if there's a more elegant approach. Bryan On Fri, 2002-08-09 at 16:52, bryan cole wrote:

I've just ported a Numeric+Python program from windows to linux and I'm generating floating point exceptions in the linux version which did not occur in windows.

I'm trying to generate a gaussian distribution by:

Input = Numeric.arange(-1024,1024)/20.0 Output = Numeric.exp(-(Input**2))

At the edges of the distribution the largish negative arguments cause the f.p. exception and prevent calculation of the entire array.

On windows the underflow errors are presumably rounded down to 0.0 automatically. Is it possible to get this behaviour on linux/ix86?

Anyone got any suggestions on a workarround for this? I see the numpy docs suggest using Masked Arrays, but since I don't know in advance which array items will generate the exceptions, I don't know which items to mask. Can the MA module generate an array mask based on f.p. exceptions from a calculation?

any suggestions would be much appreciated.

Bryan

-- Bryan Cole Teraview Ltd., 302-304 Cambridge Science Park, Milton Road, Cambridge CB4 0WG, United Kingdom. tel: +44 (1223) 435380 / 435386 (direct-dial) fax: +44 (1223) 435382

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