in reply to Re: Unfolding a nDeep structure
in thread Unfolding a nDeep structure

Thank you blockhead, I've been playing a bit with Dive. This would be part of a script were data is fed to @MDAsomeIndex in the form +1. I do not not have it behaving this way: 
#!/usr/bin/perl -w
use strict;
use Data::Diver qw[Dive DiveVal];
use Algorithm::Loops 'NestedLoops';

my @MDA;
my $dimension = 3;
my $depth = 2;


NestedLoops(
    [ ( [0..$dimension-1] ) x $depth ],
        sub {
        DiveVal( \@MDA, @_ ) = 0;
        }
    );

$MDA[0][0] += 1;

my @AoA;
for my $level (0..$dimension-1) {
NestedLoops(
    [ ( [0..$dimension-1] ) x ($depth-1) ],
        sub {
            my @indices = @_;
            my $val = Dive( \@MDA, @indices );
            push @{$AoA[$level]}, @$val;
            }
        );}

for my $row (0..$#AoA) {
    print "@{$AoA[$row]}\n";
    }

[download]
Prints:
1 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0

Updated: Expected:
1 0 0
0 0 0
0 0 0

???

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Re^3: Unfolding a nDeep structure
by blokhead (Monsignor) on Jul 05, 2007 at 23:13 UTC
    If I understand right (from looking at your example code in the OP), you want a structure that looks like this: 
    @AoA = (
  [ $MDA[0][0][0], $MDA[0][0][1], ... , $MDA[0][2][2] ],
  [ $MDA[1][0][0], $MDA[1][0][1], ... , $MDA[1][2][2] ],
  [ $MDA[2][0][0], $MDA[2][0][1], ... , $MDA[2][2][2] ],
);

    [download]
    In other words, $AoA[x] contains all the elements of the form $MDA[x][*][*], if you follow my notation.

    I don't see how this corresponds with your "Expected" data, but one thing I noticed is that you should make the following change: 

    #            my $val = Dive( \@MDA, @indices );
#            push @{$AoA[$level]}, @$val;
            my $val = Dive( $MDA[$level], @indices );
            push @{$AoA[$level]}, $val;

    [download]
    Because when dealing with $AoA[$level], you only care about things starting form $MDA[$level]. Also, then $val will not be an arrayref like it was before.

    There are many equivalent ways to write this, but another way is the following: Here you can replace the entire foreach loop with this: 

    NestedLoops(
    [ ( [0..$dimension-1] ) x ($depth-1) ],
    sub {
        my @indices = @_;
        my $val = Dive( \@MDA, @indices );
        push @{ $AoA[$indices[0]] }, $val;
    }
);

    [download]
    To explain this, it takes everything of the form $MDA[a][b][c] and pushes it onto the array at $AoA[a].

    blokhead

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