OK Ed,
in my version PDL2.098 still there does not exist whichND_both.
But, let me resume here the problem that I finally solve for a toy example:
pdl> $r=(zeroes(3,3)->ndcoords/2-pdl(0.5,0.5))->r2C
pdl> p $r
[
[
[-0.5 -0.5]
[ 0 -0.5]
[ 0.5 -0.5]
]
[
[-0.5 0]
[ 0 0]
[ 0.5 0]
]
[
[-0.5 0.5]
[ 0 0.5]
[ 0.5 0.5]
]
]
pdl> $rr=($r**2)->sumover->sqrt
pdl> ($r1,$r2)=whereND($r->using(0,1),$rr->abs < 0.3)
pdl> ($r3,$r4)=whereND($r->using(0,1),$rr->abs >= 0.3)
Here we have $r1 and $r2 the x and y coordinates for vectors
that are shorter than 0.3. In $r3 and $r4 the respective coordinates for
vectors that are larger than 0,3
pdl> $r1.=$r1+(1+i)
pdl> $r3.=$r3*(1+i)+$r4
pdl> p $r1
[
[1+i]
]
pdl> p $r3
[
[ -1-0.5i -0.5 0.5i -0.5-0.5i 0.5+0.5i -0.5i 0.5
1+0.5i]
]
We are only interested in the x coordinates of $r but of course the
modification
depends on y coordinates also. Then, in this example in one case of
condition
imposed for the mask we add 1+i and in the complement we multiply for 1+i
and
add the y coordinates
pdl> p $r
[
[
[-1-0.5i -0.5]
[ -0.5 -0.5]
[ 0.5i -0.5]
]
[
[-0.5-0.5i 0]
[ 1+i 0]
[ 0.5+0.5i 0]
]
[
[ -0.5i 0.5]
[ 0.5 0.5]
[1+0.5i 0.5]
]
]
Obtaining the desired results in $r thanks to dataflow.
Thanks, I hope to be clear now and thanks again for your
patience
Regards
El mié, 22 ene 2025 a las 18:09, Ed . (<ej...@hotmail.com>) escribió:
> Hi Guillermo,
>
> I thought you did, but it seemed worth spelling out in case people read
> the mailing-list archive later on :-)
>
> I'm not sure the solution you sent earlier is actually ugly! "If it's
> stupid but it works, it's not stupid." But I am interested to know if
> whichND_both is helpful.
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 22 January 2025 21:06
> *To:* Ed . <ej...@hotmail.com>
> *Cc:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* Re: [Pdl-devel] conditional inline
>
> Hi Ed,
> yes I realize that problem and use r2C on $r before to apply the mask,
> this work fine.
> Also yes for your comment on where_both about. Then, I try with whereND
> and obtain
> a ugly solution to my problem I guess
>
> Regards
>
>
>
> El mié, 22 ene 2025 a las 17:51, Ed . (<ej...@hotmail.com>) escribió:
>
> There's some quite complicated stuff going on here!
>
> This is a bit flawed conceptually:
> $r1.=$r1*(1+i);
> If you say .=, you're telling PDL to take the right-hand side (which will
> have complex type), and assign it *into* the existing $r1, which is
> real-typed. The only thing it can do is convert the complex-typed data into
> real data. If you change .= to =, you're making the $r1 Perl variable
> have the complex-typed ndarray, which is probably what you'd want here.
>
> This is also:
> ($r1,$r2)=where_both($r,($r**2)->sumover->sqrt < 0.2)
> Because where_both does *not* work n-dimensionally; it takes ($data,
> $mask), calls which_both on the mask (which for a multi-dimensional input
> will broadcast), then indexes (using index1d) a flattened version of $data
> with
> that.
>
> Do those points make sense?
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 21 January 2025 23:35
> *To:* Ed . <ej...@hotmail.com>
> *Cc:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* Re: [Pdl-devel] conditional inline
>
> Hi Ed,
> yes, just I was trying with where_both
> But I get unexpected behaviour for me in 2D case
>
> 1) first in 1D
>
> pdl> $r=zeroes(3)->ndcoords/2-pdl(0.5)
>
> pdl> p $r
>
> [
> [-0.5]
> [ 0]
> [ 0.5]
> ]
>
> pdl> ($r1,$r2)=where_both($r,$r->abs < 0.2)
>
> pdl> p $r1
> [0]
>
> pdl> p $r2
> [-0.5 0.5]
>
> now, trying to modify $r following that condition
>
> pdl> $r1.=$r1+1
>
> pdl> $r2.=$r2+3
>
> pdl> p $r
>
> [
> [2.5]
> [ 1]
> [3.5]
> ]
>
> But this seem did not work for complex number
>
> pdl> $r1.=$r1*(1+i)
>
> pdl> $r2.=$r2-(1+i)
>
>
> pdl> p $r
>
> [
> [1.5]
>
> [ 1]
> [2.5]
>
> ]
>
> And, seem did not work in 2D for real case neither
>
> pdl> $r=zeroes(3,3)->ndcoords/2-pdl(0.5,0.5)
>
> pdl> p $r
>
> [
> [
> [-0.5 -0.5]
> [ 0 -0.5]
> [ 0.5 -0.5]
> ]
> [
> [-0.5 0]
> [ 0 0]
>
> [ 0.5 0]
> ]
> [
> [-0.5 0.5]
>
> [ 0 0.5]
> [ 0.5 0.5]
>
> ]
> ]
>
> pdl> ($r1,$r2)=where_both($r,($r**2)->sumover->sqrt < 0.2)
>
> pdl> p $r1
> [0.5]
>
> pdl> p $r2
> [-0.5 -0.5 0 -0.5 -0.5 -0.5 0 0]
>
> what I doing wrong here?
>
> Regards
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> El mar., 21 de enero de 2025 19:42, Ed . <ej...@hotmail.com> escribió:
>
> Hi Guillermo,
>
> That does feel to me like you'd want to *not* do something on the whole
> ndarray, but instead do something on a $pdl->where(condition...). What do
> you think?
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 21 January 2025 19:07
> *To:* Ed . <ej...@hotmail.com>
> *Cc:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* Re: [Pdl-devel] conditional inline
>
> For instance, I am trying with $r, like below
>
> $r=(zeroes(2*$N+1,2*$N+1)->ndcoords-pdl($N,$N))/(2*$N+1)
>
> Regards
>
> El mar, 21 ene 2025 a las 14:39, Guillermo P. Ortiz (<
> gor...@exa.unne.edu.ar>) escribió:
>
> Yes Ed, you are right.
> I want to perform different operations on $r
> depending on its distance to a point $r0 in 2D.
> Then, I guess that first, and because for further
> manipulation, I decide to center $r-=$r0 in
> such a point.
>
> Then in false code,
>
> if ( length ($r) < $a)
> { return f($r)}
> else
> { return g($r) }
>
> where "length" I am not sure, but it could be inner($r,$r)->sqrt.
> Maybe no ternary expression but some subroutine will be fine also.
>
> Regards
>
>
>
>
>
>
>
>
>
>
>
>
> El mar, 21 ene 2025 a las 14:16, Ed . (<ej...@hotmail.com>) escribió:
>
> Hi Guillermo,
>
> That conditional will, for the case you've given, always be false, because
> it has values more than 0.2 away from 0.5. When you use all, you are
> asking a question about the entire ndarray, in other words for every single
> value in it.
>
> I believe that there's some real problem you're trying to solve, but I'm
> afraid I still have absolutely no idea what it is. Please help me help you!
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 21 January 2025 01:19
> *To:* Ed . <ej...@hotmail.com>
> *Cc:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* Re: [Pdl-devel] conditional inline
>
> Ok, Ed,
> That example did not work for me.
> The conditional results seems to be allways false. I mean, that it give $x
> also when $x is near to 0.5 than 0.2, where I is expecting the $x**2 result.
>
> Regates
>
>
>
> El El lun, 20 ene 2025 a la(s) 20:39, Ed . <ej...@hotmail.com> escribió:
>
> Hi Guillermo,
>
> You may still be having a problem, but you have yet to tell us what it is.
> The code you sent works fine, including as many dimensions as you like
> (because all acts on the whole ndarray at once).
>
> If there's a problem in there, please share it :-)
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 20 January 2025 23:35
> *To:* Ed . <ej...@hotmail.com>
> *Cc:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* Re: [Pdl-devel] conditional inline
>
> Thanks Ed,
> Using ternary conditional expression
> I still have some problem with múltiple disensión case.
> See my example in message befare
>
>
> El El lun, 20 ene 2025 a la(s) 19:31, Ed . <ej...@hotmail.com> escribió:
>
> Hi Guillermo,
>
> You can do that indeed, that's just Perl. If you wanted to do operations
> on a subset of that ndarray, then you'd do e.g.
>
> $pdl->where(($pdl-0.5)->abs < 0.2) *= 5;
>
> An observation is that the above condition could be a bit shorter by using
> the recently-added approx_artol: (which would also mean it ran quicker)
>
> $pdl->approx_artol(0.5, 0.2)
>
> Best regards,
> Ed
>
> ------------------------------
> *From:* Guillermo P. Ortiz <gor...@exa.unne.edu.ar>
> *Sent:* 20 January 2025 19:39
> *To:* pdl-devel@lists.sourceforge.net <pdl-devel@lists.sourceforge.net>;
> perldl <pdl-gene...@lists.sourceforge.net>
> *Subject:* [Pdl-devel] conditional inline
>
> Hello !
>
> I am not sure, but maybe It is possible to do with perl PDL something
> like this?
>
> $ndarray= condition on $ndarray ? assign when true : assign when false
>
> for example:
>
> $x=zeroes(20)->xlinvals(0,1);
>
> $y=(all abs($x-0.5)<0.2)?$x**2:$x;
>
> Thanks in advance
>
> Regards
>
> --
>
>
> Dr. Guillermo P. Ortiz
> Electromagnetismo Aplicado
> Dto. Física, Facultad de Ciencias Exactas
> Universidad Nacional del Nordeste
> Avda Libertad 5460
> <https://www.google.com/maps/search/Avda+Libertad+5460?entry=gmail&source=g>,
> Campus UNNE.
> W3404AAS Corrientes, Argentina.
> (+54) 379-4424678 interno 4613
> gortiz* at *unne edu ar
>
>
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