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