[dspsr-users] changes to dspsr that impact usage

[Willem v. S. <van...@gm...>]

Hi everyone,

I've checked in some fixes to dspsr so that it will continue to operate by
default as it did before the DAT_SCL and DAT_OFFS corrections (specific to
PSRFITS) were added in early 2016.  To enable the corrections, please add
"-scloffs" to the dspsr command line.

Note that the DAT_SCL and DAT_OFFS corrections are not thread-safe;
therefore, dspsr will now abort if "-scloffs" is enabled in multi-threaded
mode.

Because unique values of DAT_SCL and DAT_OFFS are stored for each
polarization, these corrections may be absolutely necessary when analyzing
full-polarization "search mode" data.  If this impacts you (and you care)
please read on below.

Cheers,
Willem

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If you regularly use dspsr to analyze PSRFITS search mode data, please let
me know what you think about the following three options:

a. make DAT_SCL and DAT_OFFS corrections the default, such that it is
necessary to disable the corrections (e.g. when you want maintain a flat
bandpass);

b. leave the DAT_SCL and DAT_OFFS corrections disabled by default, such
that it is necessary to enable the corrections (e.g. when you want to study
polarization) *[as of today, this is the default behaviour]*; or

c. leave the DAT_SCL and DAT_OFFS corrections disabled by default except
when npol == 4, in which case the corrections are automatically enabled.

Option c. makes things a bit more complicated, which makes (writing and
reading) documentation a bit more necessary; however, it might also make
dspsr behave by default in the most sensible way.

I'm open to suggestions.