Hi,
Thanks for the explanation.
Regards,
Luis
On Tue, Dec 10, 2024 at 02:20:06AM +0000, Ed . wrote:
> Hi Luis,
>
> slice gives an error if asked for a slice that's out of the bounds of the
> ndarray. I've just checked, and the docs don't say so. One could imagine an
> argument for expecting an empty answer back, but it's worked this way for
> quite a long time, and there's no way to change that now.
>
> A wrinkle is that it will only actually give the error later, when you try to
> make_physvaffine the result (e.g. by printing), which isn't very satisfactory
> on some level, but is part of the deal with "vaffine" ndarrays: they get very
> strictly lazily evaluated, not even their dimensions are ascertained
> initially.
>
> sequence(0) is a lot like zeroes(0) - you explicitly asked for an empty, so
> you got one. These, and the slice scenario, are not similar situations.
>
> Best regards,
> Ed
>
> ________________________________
> From: Luis Mochan <moc...@icf.unam.mx>
> Sent: 10 December 2024 2:08 AM
> To: perldl <pdl-gene...@lists.sourceforge.net>; perldl
> <pdl-devel@lists.sourceforge.net>
> Subject: [Pdl-devel] empty slices
>
> Hello,
>
> I wonder if the following behavior is the expected behavior:
>
> pdl> $x=sequence(2)
> pdl> p $x(0:-1)
> [0 1]
> pdl> p $x(1:-1)
> [1]
> pdl> p $x(2:-1)
> Stringizing problem: Error in slice:slice starts out of bounds in pos
> 0 (start is 2; end is -1; inc is 0; source dim 0 runs 0 to 1).
> PDL::isempty(PDL=SCALAR(0x55800a893060)) called at...
> ...
> pdl> $y=sequence(0)
> pdl> p $y
> Empty[0]
>
> Shouldn't $x(2:-1) produce an empty ndarray, as $y, instead of an error?
>
> Regards,
> Luis
>
>
> --
>
> o
> W. Luis Mochán, | tel:(52)(777)329-1734 /<(*)
> Instituto de Ciencias Físicas, UNAM | fax:(52)(777)317-5388 `>/ /\
> Av. Universidad s/n CP 62210 | (*)/\/ \
> Cuernavaca, Morelos, México | moc...@fis.unam.mx /\_/\__/
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>
>
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--
o
W. Luis Mochán, | tel:(52)(777)329-1734 /<(*)
Instituto de Ciencias Físicas, UNAM | fax:(52)(777)317-5388 `>/ /\
Av. Universidad s/n CP 62210 | (*)/\/ \
Cuernavaca, Morelos, México | moc...@fis.unam.mx /\_/\__/
GPG: 791EB9EB, C949 3F81 6D9B 1191 9A16 C2DF 5F0A C52B 791E B9EB
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