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Re: st: Mata fopen() and memory, manual error
Matissa Hollister <[email protected]> asked about Mata and Mata's function
-fputmatrix()-:
> The Mata manual says that fputmatrix stores matrices
> in a compact and efficient format. Also, assuming my
> reading is correct, more than one matrix can be saved
> into a single file. [...]
Yes, more than one can.
> [...] I'm planning to run analysis that
> will do several iterations of a mata function I have
> written with a moderately large matrix as the output
> (perhaps as large as 1000x1000). My inclination is to
> append the resulting matrices all to one file, thereby
> reducing clutter in my folders. When I finally use
> the results, though, I'll only use one matrix at a
> time (passing it into a clustering program). I'm
> wondering whether there are memory or other reasons
> for keeping the matrices in separate files. For
> instance, when you use the command fopen()does it read
> the entire contents of the file into memory? [...]
-fopen()- does NOT read the contents of the file into memory.
> On a related note, I think there might be an error on
> p. 359 of the Mata manual. The sample code at the top
> of the page says:
>
> fh_in = fopen(inputname, "r")
> fh_out = fopen(outputname, "w")
> while ((c=fread(fh_in,1))!=J(0,0,"") {
> fwrite(fh, (c=="a" ? "b" : c))
> }
> fclose(fh_out)
> fclose(fh_in)
>
> shouldn't the fourth line be:
> fwrite(fh_out, (c=="a" ? "b" : c))
Yes. The same error appears in the on-line help, too.
-- Bill
[email protected]
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