sub perms {
    my ($n, $min) = @_;
    $min //= 2;
    return [] if $n <= 0;  
    return [$n] if $n <= $min;

    my @r;
    foreach my $i ($min .. $n) {
        my $left = $n - $i;
        next if $left < $min;
        my @p = perms $left, $i;
        foreach my $p (@p) {
            push @r, [@$p, $i];  
        }
    }
    @r;
}

say "[@$_"] for perms 7;
__END__
[2 3 2]
[3 4]
[2 5]

[download]
It's not fast, but that's because of the enormous amount of ways to decompose numbers.

In reply to Re: Decomposing sum to unique sets of summands by JavaFan
in thread Decomposing sum to unique sets of summands by blackmanao

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.