197 * 8000 = 1576000. If you only have 1.5e6 data points why are you trying to match them against 4**21 possible combinations when all bar an infinitessimal fraction of those won't be present?

Just compare your 1.5e6 against themselves and mark everything else as zero. No matrices required.

For fun, see The 10**21 Problem (Part I) and the subsequent parts.

(Edit: BrowserUk managed to construct a fuller and therefore better response in the time it took me to deduce and type this. Still, great minds and all that ;-)

In reply to Re^3: Out of Memory when generating large matrix by hippo
in thread Out of Memory when generating large matrix by cathyyihao

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.