My approach would start from setting the zeroes to randomly 1 or 0 first, then using https://metacpan.org/pod/PDL::Primitive#clip (untested): 
$inds = $x->whichND($x == 0);
$x->indexND($inds) .= ($x->random < 0.5)->indexND($inds);
$x->inplace->clip(0,1);

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This would obviously benefit enormously from loop fusion or making your own custom PDL operation.

In reply to Re: PDL, applying function by etj
in thread PDL, applying function by rootcho

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