<div dir="ltr">Neil's being way too kind when he mentions RSound. It's true that I add DSP functions into RSound as I need them for first-year classes, but I would *love* to see / help with a real DSP library. It seems to me like such a library would probably be built on ... 1-d Arrays of Float? ... and probably use typed racket for speed. If you have experience using SciPy's DSP libraries, it would be lovely to see a "wish list" of the most important functions and abstractions that they use. </div><div class="gmail_extra"> <div class="gmail_quote">On Wed, Feb 4, 2015 at 9:31 AM, Neil Toronto <<a href="mailto:neil.toronto@gmail.com" target="_blank">neil.toronto@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Awesome! It's great to have you with us. On 02/04/2015 05:28 AM, Marmaduke Woodman wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> [...] 1) The plotting library doesn't seem to have the equivalent of MATLAB/MatPlotLib's imagesc/imshow, which simply plots a rectangular colormap of the matrix. [1] </blockquote> You can use Plot and `images/flomap` together to do this, but it would be nice to make it easier. To get you started, here's an adaptation of the plotting example from the "Overview" section of the flomap docs: #lang racket (require images/icons/misc ; for bomb-flomap plot/utils ; for color-seq images/flomap plot) (define icon-fm (bomb-flomap #:bomb-color "orange" #:height 64)) (flomap->bitmap icon-fm) (define-values (icon-width icon-height) (flomap-size icon-fm)) ;; Plot the red channel (plot (contour-intervals (λ (x y) (flomap-bilinear-ref icon-fm 1 x (- icon-height y))) #:levels 10 #:colors (λ (ivls) (color-seq "black" "white" (length ivls))) #:contour-styles '(transparent) #:samples (+ 1 icon-height) -0.5 (+ 0.5 icon-width) -0.5 (+ 0.5 icon-height))) <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> 2) Arbitrary meshes in 3D: say I have a set of vertices and triangles. How can I plot the mesh and change edge & face properties? Given that 3D surface plotting is possible, plotting meshes seems necessarily possible but is not documented. Do I need to use GL for this? </blockquote> Previously, Plot could only handle meshes that had two dimensions aligned to a grid. Now it has a decent 3D backend that can handle any mesh, but I haven't added a `triangles` function to it yet. The "pict3d" package, which uses OpenGL, can do this easily, but it's not ready for serious use yet. I just got it to run on all 3 of our officially supported platforms (Windows, Mac, Linux). <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> 3) The array & linear algebra libraries were a happy find. Is there any way I can contribute there? </blockquote> Yes. Very yes! We most need a `math/signal` module, and matrix LUP, SVD, and Eigen decompositions. I'd like to hook the matrix library into LAPACK on systems where it's available. But defining FFIs as an advanced task, worth trying only after you've programmed in Racket for a while. <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Are there plans to flesh out a larger set of scientific libraries as in SciPy (optimization, signal processing, for example) </blockquote> Yes! If you'd like to work on any of these, we'd love it if you'd contribute. Be aware that, like SciPy, we can't accept anything derived from GPL-licensed code such as the GNU Scientific Library or R's standard library. We *can* accept anything derived from code licensed at least as permissively as ours (which is LGPL), such as SciPy (which is BSD) or C++'s Boost (which has its own permissive license). <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> 4) Do any signal processing packages currently exist? I couldn't find anything on planet. Specifically I'd just like to design and apply a Butterworth filter to data, so maybe I can write that up myself, but existing work is welcome. </blockquote> The "rsound" package does signal processing. I don't know how much of it is in its public API. The only signal-processing-related functions in Racket's standard library are in `math/array`: `array-fft` and its inverse, and corresponding per-axis FFT functions. Again, we'd love to get contributions, and welcome to the club! Neil ⊥<div class="HOEnZb"><div class="h5"> ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </div></div></blockquote></div> </div>