PSRCHIVE 8.1 file format-specific release notes

PSRCHIVE 8.1 added support for several new file formats. Here is a list of known issues with each of these.

For all new data types (ASP, WAPP, BPP):

  • PSRCHIVE only reads these formats, it doesn't write them. For any operations that modify the files, it's best to convert to PSRFITS first, using either the "pam" or "psrconv" programs.
  • In principle the new code works on both big-endian (Sun, etc) and little-endian (Intel, etc) machines. However, development and testing has been done mainly on Linux/PCs. If anyone experiences problems that may be related to this, please report them!

For WAPP data:

  • Folded WAPP file versions 2 through 9 are handled, however only versions 8 and 9 have been tested. If anyone runs into any problems with old versions, please let Paul know.
  • PSRCHIVE converts WAPP ACFs ("lags") to spectra using a slightly different method than Sigproc and Presto (DCT-III rather than a real-to-complex FFT). This results in correct channel frequencies, with no half-channel offset. See this for a detailed description of the issue.
  • The quantized power (aka Van Vleck) correction is not fully working for either 9-level or full-Stokes WAPP modes. Does anyone actually use these modes?
  • WAPP files typically don't have a filename extension (for example "p2178.B1937+21.wapp1.54135.0006"). Some PSRCHIVE data-conversion programs will try to change the extension and end up removing the scan number (0006 in the example) in the process. It's best to add a ".wapp" to WAPP filenames before messing with them.

For BPP data:

  • There is still some remaining work to fully implement the infamous "midscan correction." So don't expect super-precise timing results from BPP files yet. This is on the list of things to fix.
  • The new PSRCHIVE code uses a different (hopefully more correct) 2-bit quantized power correction than the older Berkeley "ctoa" code. This applies to all observing modes, but especially affects polarization cross-terms. Anyone interested in details should contact Paul.