https://rosettacode.org/wiki/Resistor_mesh#J might interest you...
--
Raul
On Fri, Jul 28, 2017 at 12:56 AM, Brian Babiak <bdbab...@gmail.com> wrote:
> I’m working on a project to compute the distance resistance between two
> vertices in an electronic grid. I will share that later. But I am having
> domain error issues with matrix inverse and matrix product operations. See
> the following:
>
>
>
> f=.2 2$3 4 1 4
>
> g=.2 2$i.2
>
> h=.2 2$_3 4 2 _3
>
>
>
> 2 3$'f';'g';'h';f;g;h
>
> ┌───┬───┬─────┐
>
> │f │g │h │
>
> ├───┼───┼─────┤
>
> │3 4│0 1│_3 4│
>
> │1 4│0 1│ 2 _3│
>
> └───┴───┴─────�
>
>
>
> 2 3$'$f';'$g';'$h';($f);($g);($h)
>
> ┌───┬───┬───┐
>
> │$f │$g │$h │
>
> ├───┼───┼───┤
>
> │2 2│2 2│2 2│
>
> └───┴───┴───�
>
>
>
> f . g
>
> |domain error
>
> | f .g
>
> f . h
>
> |domain error
>
> | f .h
>
> %. f
>
> 0.5 _0.5
>
> _0.125 0.375
>
> %. g
>
> |domain error
>
> | %.g
>
> f . f
>
> |domain error
>
> | f .f
>
> g . g
>
> |domain error
>
> | g .g
>
> h . h
>
> |domain error
>
> | h .h
>
> h * g
>
> 0 4
>
> 0 _3
>
>
>
> The answers to all these operations are simple. Why are there these domain
> errors?
>
>
>
> Here is the project this issue is coming up in, although I believe it is more
> basic than that.
>
>
>
> vw=: (,@(((_ 0)$~#@:])`]`(1$~,~@:}.@[)}))`(,@(((0
> _)$~#@:])`]`(1$~,~@:}.@[)}))@.(<:@:({.@:[))
>
> NB. (moveno boardsz) nw (x1 y1;x2 y2; etc)
>
> NB. Gives vertex weights for a move list of a game as vector
>
>
>
>
>
> rows=: <"1
>
> cols=: <"1@|:
>
> diags=: (-.((0;_1)&{))@:(</.)
>
> a=: 3 3$i.9
>
> conndiag=: 3 : 0
>
> r=. r,.|.r [ r=. >0{z [ i=. 1 [ n=. #z [ z=. diags y
>
> while. i<n do.
>
> col=. >i{z
>
> i=. >:i
>
> adds=. >2<\col
>
> r=. r,adds
>
> r=. r,(|."1 adds)
>
> end.
>
> )
>
>
>
> connsq=: 3 : 0
>
> r=. 0 2$0 [ i=. 0 [ n=. #z [ z=. y
>
> while. i<n do.
>
> col=. >i{z
>
> i=. >:i
>
> adds=. >2<\col
>
> r=. r,adds
>
> r=. r,(|."1 adds)
>
> end.
>
> )
>
> connrws=: connsq@:rows
>
> conncls=: connsq@:cols
>
>
>
> edges=: 3 : 0 NB. takes board size as argument
>
> a=. (2$bs)$i.*:bs [ bs=. y
>
> r=. (connrws a),(conncls a)
>
> r=. r,conndiag a
>
> )
>
>
>
> BOARDSZ=: 5
>
> EDGES=: edges BOARDSZ
>
> VPLYR=: 1 NB. whether the vertical player is first or second
>
>
>
> A=: 3 : 0
>
> mat=. (2$netsz)$0 [ netsz=. *:BOARDSZ [ j=. 0 [ i=. 0 [ arg=. VPLYR,BOARDSZ
>
> if. y=0 do. pcweights=. netsz$1 else. pcweights=. arg vw y end.
>
> while. i<netsz do.
>
> while. j<netsz do.
>
> mat=. (0{(((1 2$i,j) e. EDGES)*((i{pcweights)+j{pcweights))) (<(i,j))}mat
>
> j=. >:j
>
> end.
>
> j=. 0
>
> i=. >:i
>
> end.
>
> mat
>
> )
>
>
>
> D=: 3 : 0
>
> diag=. (2$netsz)$ 1,netsz#0 [ netsz=. *:BOARDSZ [ colsum=. +/y [ y=. A y
>
> r=. colsum*diag
>
> )
>
>
>
> L=: D-A NB. the Laplacian
>
>
>
> NB. %. Laplacian or . (dot) for Laplacian times current gives domain errors
>
>
>
> Any help would be appreciated!
>
>
>
> Brian Babiak MD
>
> https://drbabiak.com
>
>
>
>
>
> ----------------------------------------------------------------------
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----------------------------------------------------------------------
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