Re^3: Performance problem with Clone Method

[dcmertens]

BrowserUK, you don't think this is actually a problem, do you? PDL is a very mature Perl extension that handles high dimensional data sets very nicely. In fact (surprise!) there's more than one way to do it. At the moment, I believe the best documentation for beginners is the Matlab or Scilab migration guides. They say that PDL::QuickStart is a better place to start, but I humbly disagree. See http://pdl.perl.org/?docs=Tutorials&title=PDL::Tutorials for the (short) list of tutorials available.

To answer your specific question, suppose you have a 2x4 piddle, perhaps created with the sequence command. A snippet of your code might look like this:

my $pdl = sequence(2,4);

If you wanted to modify the (0,3) element of the array (first column, last row), you would use NiceSlice and the .= notation like so:

$pdl(0,3) .= -4;

A full working example would look like this:

use strict;
use warnings;
use PDL;
use PDL::NiceSlice;

my $pdl = sequence(2,4);
print "$pdl\n";
$pdl(0,3) .= -4;
print "$pdl\n";

The output looks like this:

[
 [0 1]
 [2 3]
 [4 5]
 [6 7]
]


[
 [ 0  1]
 [ 2  3]
 [ 4  5]
 [-4  7]
]

Edit: revised the opening paragraph to be more useful

Edit2: re-revised the opening paragraph to be even more useful

Edit3: used code tags instead of pre tags for example code and ouput