Hi Luis, "einops" stands for (in part) "Einstein inspired notation" (for doing dimension-manipulation in n-dimensional arrays, currently in Python). It would be a good idea to read that quite concise web-page by its creator, since it's interesting stuff; what it isn't is directly using Einstein summation.
Best regards, Ed ________________________________ From: Luis Mochan <moc...@icf.unam.mx> Sent: 14 January 2025 04:55 To: Ed . <ej...@hotmail.com> Cc: Ingo Schmid <ingo...@gmx.at>; pdl-general@lists.sourceforge.net <pdl-general@lists.sourceforge.net> Subject: Re: [Pdl-general] [Pdl-devel] Pdlpp modules Hi Ed, On Tue, Jan 14, 2025 at 02:44:36AM +0000, Ed . wrote: > Hi Luis, > > I did in fact look at ApplyDim when you posted it on CPAN, because on the IRC > channel we have a bot that reports whenever a module starting with "PDL" is > uploaded to CPAN. Please believe me when I say I know extremely well that > it's not currently possible to skip mv/reorder/whatever. What I'm saying is > it ought to be possible to tell PDL to just do its "*over" operation along a > different dimension. I don't know how PDL actually moves dimensions around. Would doing *over operations along different dimensions be less expensive than reordering and performing over the first dimensions? > This evening, it occurred to me a possible answer to the problem of how to > express such a thing might lie in "einops" > (https://github.com/arogozhnikov/einops). That would certainly also offer > ideas in how to express dim-naming stuff also. Einstein's notation is compact and expressive. It is great generally, but not always, and it is cumbersome where it can't be used directly. For example, making a weighted sum of products of elements of a and b with weights w, sum_i(h_i a_i b_i) is written in Einstein's notation as g_{ij} a_i b_j where g_{ij} is a special metric, a matrix with diagonal elements h_i and zeroes elsewhere. I guess computationally you wouldn't want to do that (multiply every a_i by every b_j and then the result by g_{ij} which is mostly zeroes and do a double sum over i and j). I haven't looked though at any details of einops yet. Best regards, Luis > > Best regards, > Ed > > ________________________________ > From: Luis Mochan <moc...@icf.unam.mx> > Sent: 14 January 2025 02:23 > To: Ed . <ej...@hotmail.com> > Cc: Ingo Schmid <ingo...@gmx.at>; pdl-general@lists.sourceforge.net > <pdl-general@lists.sourceforge.net> > Subject: Re: [Pdl-general] [Pdl-devel] Pdlpp modules > > On Mon, Jan 13, 2025 at 07:33:34PM +0000, Ed . wrote: > > I have some awareness of PDL::Dims... > > > > And on the subject of capabilities I think should be stolen into core PDL, > > I believe "apply an operation over dims other than 0" is another. > > Have you looked at PDL::ApplyDim? It doesn't skip the mv nor reorder > operations, it just hides them away so the user doesn't have to keep > track of how the dimensions were shuffled before applying an operation > nor how to unshuffle them afterwards. He just have to state which > dimension(s) should come to the front or to the back before applying > the operation. > > 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 /\_/\__/ > GPG: 791EB9EB, C949 3F81 6D9B 1191 9A16 C2DF 5F0A C52B 791E B9EB -- 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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