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Truncating files [message #2674]

Wed, 24 August 1994 10:20

eharold
Messages: 12
Registered: July 1993

Junior Member

My coode performs FFT's and inverse 3-D FFT's on very large
(>= 100 megabytes) data sets. Thus most of the data is on disk at any one
time. To avoid aliasing I've zero-padded the data before convolution
with my filter function. Eventually I need to throw away the padding
values after the inverse transform has been completed. They're all located
at the end of the file so I just want to truncate the file to the appropriate length. Does anyone know a convenient way to do this from within IDL
on a SUN Sparc running SunOS 4.1.3 or Solaris 2.3? Disk space is tight
so I'd rather not waste all the time and space by rewriting all the
data values I really want to a separate file if I could just truncate
an already existing file.

--

Elliotte Rusty Harold National Solar Observatory
eharold@sunspot.noao.edu Sunspot NM 88349

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Truncating files

By: eharold on Wed, 24 August 1994 10:20

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