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From: mcqueen@acf4.NYU.EDU (David M. McQueen)
Newsgroups: comp.lang.fortran
Subject: Re: slow write
Message-ID: <13160005@acf4.NYU.EDU>
Date: 22 Mar 90 20:30:00 GMT
References: <3673.2607e3bb@vax5.cit.cornell.edu>
Organization: New York University
Lines: 42

/* acf4:comp.lang.fortran / h3dy@vax5.cit.cornell.edu /  7:27 pm  Mar 21, 1990 */
> I have a large array (characters) that I read in, process,
> then write out to a file.  Prior to run time, I dont know
> the final number of elements - it is smaller than the original.
> 
>       write (10) array
> 
> is fast, but if the array is much smaller, I don't want to
> do this.
> 
>       write (10) (array(i),i=1,n)
> 
> but an implied do is very very slow!  How can I get the
> combine the advantages whilst avoiding the disadvantages?
> My array is about 15000000 characters long initially.
> 
> I am embarrassed to say I tried equivalencing arrays of
> different sizes, using the closest one.  Ugliness.
> 
> Thanks for the help, sorry if this appears 2x, pnews is "broken"
> so I am using anunews.
/* ---------- */

How about this:

      program main
      dimension array(large)
      .
      .
      .
      call out(array,ismall)
      .
      .
      .
      subroutine out(array,ismall)
      dimension array(ismall)
      write(10) array
      return
      end

You might want to also write out the value of ismall for the benefit of the
program which reads the file.