Hi Luis, As you may have seen in the pdl repo, I've now added both spline (using pchip_chsp) and PCH (piecewise cubic Hermite (which is what PCHIP stands for)), using pchip_chim) interpolation. There isn't yet an options to add control of boundary conditions, but I'm thinking an additional boundary option for the ic and vc settings, and changing from pchip_chic to pchip_chim.
Thoughts? Best regards, Ed ________________________________ From: Luis Mochan <moc...@icf.unam.mx> Sent: 11 January 2025 02:54 To: Ed . <ej...@hotmail.com> Cc: Boyd Duffee <boyd.duf...@gmail.com>; pdl-devel <pdl-devel@lists.sourceforge.net>; perldl <pdl-gene...@lists.sourceforge.net> Subject: Re: [Pdl-devel] curl of vector Hi Ed, all, On Tue, Jan 07, 2025 at 08:16:56PM +0000, Ed . wrote: > Hi Luis and all, > > Two points: > > ... > I've now added a Ufunc::diffcentred (based on Luis's rotate algorithm), and Ufunc::partial; Great! > the latter adjusts Luis's work to take an ndarray as first param so it can be > a method, and takes instruction on which method to use (centred (default), > forward, backward). I'm about to add a PCHIP option too, currently only using > https://metacpan.org/pod/PDL::Primitive#pchip_chim, but it would be possible > to use pchip_chic which offers more control of boundary conditions. Feedback > welcome. I was not aware about the pchip functions (what does the acronym stand for?). I had used the PDL::Ufunc module to make Hermite interpolations. As I read, the pchim_chim derivatives apply only to monotonic functions. For others, it produces a piecewise monotonic result with extremes at data points. The chip_chic seem to be more general and admit different choices of boundary conditions. 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
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