Thread: detecting "inf" and "nan" in sac

Hello,

This is a follow up question I asked below.

I found a reference to isnan() call at
http://www.iris.washington.edu/pipermail/sac-dev/2008-January/000058.html
that says:
BUG FIX: isNaN() unsuitable for double, changed to system
command isnan(). Found while checking polezero constants.

Is is possible to use isnan() and isinf() in a sac macro directly or indirectly?

How else could I detect the nan and inf while in macro? It seems that
the if loop below doesn't do a job (at least for me).

I know I can implement this function in fortran through readsac1 but I
am trying to write this in sac a macro only.
Would you recommend not to do it for whatever reason?

Thank you,
Igor


On Tue, Aug 16, 2011 at 10:53 PM, Igor Stubailo <stubailo<at>gmail.com> wrote:

Hello,

Is there any way to detect a non-number value (like inf and nan) in an if loop?
I couldn't find any references to this in the manual.
All versions below are simply ignored by sac:

mtw %min %max
rms to user0
setbb sta &1,user0

*** doesn't work:
if %sta eq inf
message "***** not a number  ******"
endif

*** doesn't work:
if %sta eq "inf"
message "***** not a number  ******"
endif


Note, this works:
if %sta eq 0
message "***** detected zero ******"
endif

Thanks,
Igor