[Lofarpwg] Fwd: [Everyone] PSRCHIVE bug: PSRFITS data systematically attenuated

[Jason Hessels]

Hi All,

You probably received this from Willem directly (if you’re on the “Everyone” pulsars mailing list), but if not… then “FYI".

Cheers,

Jason

-----

Dr. Jason W. T. Hessels

Chief Astronomer - ASTRON, Netherlands Institute for Radio Astronomy
Associate Professor (Universitair Hoofddocent) - University of Amsterdam
Member De Jonge Akademie - dejongeakademie.nl
Mobile Tel: +31 (0)610260062

> Begin forwarded message:
> 
> From: Willem van Straten <vanstraten.willem at gmail.com>
> Subject: [Everyone] PSRCHIVE bug: PSRFITS data systematically attenuated
> Date: 15 December 2020 at 10:25:41 CET
> To: psrchive-users at lists.sourceforge.net, psrchive-developers at lists.sourceforge.net, everyone at lists.pulsarastronomy.net
> 
> Hi everyone,
> 
> Today, I checked in a couple of PSRCHIVE bug fixes that may have a small impact on your data.  These bugs are relevant only to PSRFITS file I/O.
> 
> 1. To date, when writing data to a PSRFITS file, PSRCHIVE has been converting floating point values to signed 16-bit integers by truncation (casting as opposed to rounding).  This has the effect of systematically decreasing the range of values in the data (e.g. -1.999 is truncated to -1 and +1.999 is truncated to +1).
> 
> 2. Since April 2016, when writing data to a PSRFITS file, PSRCHIVE has effectively been using only 15 of the 16 bits, which effectively doubles the rounding error.
> 
> You can read more about these errors and the bug fixes at
> 
> https://sourceforge.net/p/psrchive/bugs/440/ <https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsourceforge.net%2Fp%2Fpsrchive%2Fbugs%2F440%2F&data=04%7C01%7Cj.w.t.hessels%40uva.nl%7C0258a5613a84499201a708d8a0dbaf2e%7Ca0f1cacd618c4403b94576fb3d6874e5%7C1%7C0%7C637436212679586564%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=JOANpkfi1BRfwapcwZC4cZX5hfvOs%2FQNTm03tfnWXk8%3D&reserved=0>
> 
> Please update your PSRCHIVE installation and let everyone know if you discover any issues that are greater than those encountered so far (described at the above link).
> 
> Cheers,
> Willem
> 
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