Dear Ingo, On Wed, May 22, 2019 at 02:15:24AM +0200, Albrecht Ingo Schmid wrote: > Dear all, > > I've been working on native complex number support and got it to the > stage of passing all tests on my linux box. Each element of a piddle is > a complex number, no more hassle whether the first dimension needs to be > two or not. Essentially it adds binding to C's complex.h.
This is great news! pdl> $a=sequence(5)+ci()*sequence(5)*2 pdl> p $a [0+0i 1+2i 2+4i 3+6i 4+8i] pdl> p $a->info PDL: CDouble D [5] pdl> looks great (a 5 element 1-D complex pdl) instead of the previous version pdl> use PDL::Complex pdl> $b=sequence(5)+i*sequence(5)*2 pdl> p $b [0 +0i 1 +2i 2 +4i 3 +6i 4 +8i] pdl> p $b->info PDL::Complex: Double D [2,5] pdl> which is a PDL::Complex (which some routines, such as those in FFTW3 don't understand as a PDL) and is a 2x5 2 dimensional array. This has produced some confusion (for example, reductions on these complex arrays should iterate on the second, not the first index). > > Check out the nat_c2 branch here, all others are irrelevant and should > be deleted: > > https://github.com/fantasma13/pdl > > Use cdouble, cfloat, ci() (imaginary unit), cimag, creal, abs, carg to > convert. Most basic functions should work as expected from complex math, > please report any odd behaviour. > > The FFT module should play along. I'd love to see the same for FFTW3. Currently, FFTW3 works on 2xN real PDL's which could be obtained from a PDL::Complex value using the function 'real', as in $c=sequence(2,5)->complex, $r=$c->real. This could then be fed to the FFTW3 routines. Are there conversions between the new complex N-pdl's and real 2xN pdl's? Or should one take real and imaginary parts and them somehow join them? Just experimenting I tried combining the two kinds of complex numbers with funny results pdl> p $a [0+0i 1+2i 2+4i 3+6i 4+8i] pdl> p $b [0 +0i 1 +2i 2 +4i 3 +6i 4 +8i] pdl> p $a+$b [0+0i +0+0ii 2+2i +2+0ii 4+4i +4+0ii 6+6i +6+0ii 8+8i +8+0ii] pdl> p $a->info PDL: CDouble D [5] pdl> p $b->info PDL::Complex: Double D [2,5] pdl> p +($a+$b)->info PDL::Complex: CDouble D [2,5] with a PDL::Complex that takes a complex double for real part and another for imaginary part (with funny double 'ii's). I guess that the two kinds don't mix. I wonder why you need the parenthesis in ci()? The old imaginary unit i doesn't needs them. pdl> $a=sequence(5)+ci()*sequence(5)*2 pdl> p $a [0+0i 1+2i 2+4i 3+6i 4+8i] pdl> $a=sequence(5)+ci*sequence(5)*2 syntax error at (eval 120) line 4, near "*sequence(" pdl> $b=sequence(5)+i*sequence(5)*2 pdl> p $b [0 +0i 1 +2i 2 +4i 3 +6i 4 +8i] though pdl> $a=sequence(5)+sequence(5)*2*ci with ci at the end without parenthesis does work. > > There are two general issues I've come across: Implicit type conversion > to the next datatype that allows a specific operation. I've seen two > examples while working on this: > ... Thanks for this welcome development! Regads, Luis -- o W. Luis Mochán, | tel:(52)(777)329-1734 /<(*) Instituto de Ciencias Físicas, UNAM | fax:(52)(777)317-5388 `>/ /\ Apdo. Postal 48-3, 62251 | (*)/\/ \ Cuernavaca, Morelos, México | moc...@fis.unam.mx /\_/\__/ GPG: 791EB9EB, C949 3F81 6D9B 1191 9A16 C2DF 5F0A C52B 791E B9EB _______________________________________________ pdl-devel mailing list pdl-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pdl-devel
