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Comment by rwlincoln | Hacker News Reader

Satisfying the BLAS/LAPACK dependency was one of the biggest challenges. I ended up passing LAPACK 3.4.2 through f2c before compiling the result with emcc. PCRE and some SuiteSparse libraries were the only additional dependencies needed for my project and they compiled with Emscripten without too much difficulty. The rest was just hacking GNU Octave's Autotools build system, which gleans a lot of information from the system environment, into working with emconfigure and emmake. My changes to the GNU Octave source code are available here:

https://github.com/rwl/octave-4.4.1/tree/web-assembly

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This is very interesting and would never have guessed that it is possible. I would love to read a more detailed write up how all this works (is everything bundled to a large blob for the octave interpreter for example?). Also is the a specific reason you used v4.4.1? And playing with the PWA everything seems instant, but Octave is ~1Gb installed, wouldn't the Octave wasm have to be downloaded to the client (which it doesn't seem to do)?

The GNU Octave interpreter and its dependencies are all in the matpower.wasm file. 19Mb is still quite large for a website, but it is loaded asynchronously and WASM get compiled as it streams in. The interpreter runs in a WebWorker using a Promise based interface so the UI doesn't get held up. Many of the dependencies (e.g. FFTW, CHOLMOD, ARPACK, Qt, HDF5) are disabled as they are not needed to run MATPOWER. There was no particular reason for using v4.4.1. The core functionality of GNU Octave doesn't change much and that version was stable and sufficient for my needs.

Thank you for explaining, I will have to explore this further as this opens up a lot of interesting possibilities. I find it very impressive that you have managed to get virtually no perceptible loading time at all, for octave running on a client (I remember threads now and then about statically compiling octave for portability which all eventually end up with it not being possible so I would never have guessed this was viable).

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