Problem with %f in printf

emma · Posted: Wed May 23, 2012 10:38 pm Post subject: Problem with %f in printf

Hi Mike,

I've just come across a weird behaviour when using %f in printf. I've noticed this happens with IRAF 2.14.1 and IRAF 2.15.1a (but not with PyRAF):

emma · Posted: Wed May 23, 2012 10:41 pm Post subject:

*forward* slash (sorry!)

fitz · Posted: Wed May 23, 2012 10:47 pm Post subject:

What platform is this, it seems to work fine on v2.16 macintel. Note that the CL implements the 'real' type internally as double-precision which explains the extra digits, pyraf simply has it's own printf() function.

emma · Posted: Wed May 23, 2012 10:55 pm Post subject:

This is on my redhat linux machine (RHEL 5).

I'm not worried about the extra digits, just the trailing forward slash that shouldn't be there Wink

Thanks!

Emma Smile

fitz · Posted: Sun May 27, 2012 6:28 am Post subject:

I can confirm this is still present in the latest v2.16 system, but only on 32-bit linux systems. It appears to be some sort of round-off problem in the converter code, i.e. if the test value is 1.0, or 5.0, or 2.0 then the last character will be different. A '/' char comes immediately before a '0' in ascii but the converter isn't constraining the result.

I'll fix this for the next update, the workaround for now is to specify some level of precision, e.g. "%.8f"

emma · Posted: Tue May 29, 2012 2:55 pm Post subject:

Thanks, Mike! Smile