I think you want the `matrix-ref` function. Sam On Sun, Oct 7, 2018 at 12:30 AM Ricardo Iglesias <ricardoa.igles...@gmail.com> wrote: > > Sorry for the confusing wording. > Basically, All I want is to be able to do > G[ row ][ col ] = value > > In Racket. I've been messing with Racket this afternoon and have an engine > that is able to index into matrices, and just implemented several common > matrix operations, such as transpose, matrix multiplication, etc..., so for > now, I'm good. > > > On Saturday, October 6, 2018 at 8:47:41 PM UTC-7, cwebber wrote: >> >> Ricardo Iglesias writes: >> >> > Good afternoon. I'm trying to move away from things like Matlab and SciPy >> > to do linear algebra work. >> > Something I notice I do a lot is indexing operations, such as >> > MATRIX[ row ] [ column ] >> > >> > I'm looking at the "math/matrix" library provided here: >> > https://docs.racket-lang.org/math/matrices.html, and don't see anything of >> > this sort; I only see things like >> > (matrix-map-rows) >> > >> > and >> > (matrix-map-cols) >> > >> > Being able to access and modify a particular entry in the matrix would be >> > very useful in specifying operations to matrices. For example, given a >> > matrix *G*, one might want to perform indexing operations to get the matrix >> > attached. >> > >> > Is this possible with the math/matrix library? >> > >> > Additionally, would there be a way to implement a version of >> > matrix-map-row/cols that uses an index? >> >> Not quite what you're asking, but someone at RacketCon suggested to me >> that maybe we should get GNU Scientific Library bindings added to >> Racket, so we can better compete with Python and R for scientific / >> statistical work... > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout.

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