PDL How to create/initialise a large byte piddle directly.

BrowserUk has asked for the wisdom of the Perl Monks concerning the following question:

I can initialise a large 2D piddle using zeroes and then convert that to a byte piddle:

perldl> $a = zeroes 1000, 1000
perldl> $b = byte $a
perldl> help vars
PDL variables in package main::

Name         Type   Dimension       Flow  State          Mem
----------------------------------------------------------------
$a           Double D [1000,1000]          P            7.63Mb
$b             Byte D [1000,1000]          P            0.95Mb
[download]

I can then undef $a to discard the default Double piddle and recover space

perldl> undef $a
perldl> help vars
PDL variables in package main::

Name         Type   Dimension       Flow  State          Mem
----------------------------------------------------------------
$b             Byte D [1000,1000]          P            0.95Mb
[download]

And I can do that all in one line:

perldl> $c = byte zeroes 1000,1000
perldl> help vars
PDL variables in package main::

Name         Type   Dimension       Flow  State          Mem
----------------------------------------------------------------
$c             Byte D [1000,1000]          P            0.95Mb
$b             Byte D [1000,1000]          P            0.95Mb
[download]

but it appears as if the latter still creates the 8-times bigger intermediary before automatically discarding it.

Is there a way to create a large 2D byte piddle directly?

I'm just starting to find my way around the PDL docs and I seem to be missing this example.

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Comment on PDL How to create/initialise a large byte piddle directly. Select or Download Code

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Re: PDL How to create/initialise a large byte piddle directly. by explorer (Chaplain) on Oct 19, 2006 at 23:03 UTC
From PDL::Core: `$c = zeroes( byte, 1000, 1000);` [download] Update: Is VITAL for you to subscribe to pdl mailing list!	[reply] [d/l]

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