@thi.ng/tensors/mulm.js

0D/1D/2D/3D/4D tensors with extensible polymorphic operations and customizable storage

import { assert } from "@thi.ng/errors/assert";
import { tensor } from "./tensor.js";
const mulM = (out, a, b) => {
  const {
    data: adata,
    offset: oa,
    shape: [sxa, sya],
    stride: [txa, tya]
  } = a;
  const {
    data: bdata,
    offset: ob,
    shape: [sxb, syb],
    stride: [txb, tyb]
  } = b;
  assert(
    sya === sxb,
    `incompatible matrix shapes, matrix b requires ${sya} rows`
  );
  if (out == null) {
    out = tensor(a.type, [sxa, syb], { storage: a.storage });
  }
  const {
    data: odata,
    offset: oo,
    shape: [sxo, syo],
    stride: [txo, tyo]
  } = out;
  assert(
    sxo === sxa && syo === syb,
    `incompatible output matrix shape, expected: [${sxa},${syb}]`
  );
  let oax, oox, oby, i, j, k, sum;
  for (i = 0; i < sxa; i++) {
    oox = oo + i * txo;
    oax = oa + i * txa;
    for (j = 0; j < syb; j++) {
      oby = ob + j * tyb;
      sum = 0;
      for (k = 0; k < sya; k++) {
        sum += adata[oax + k * tya] * bdata[oby + k * txb];
      }
      odata[oox + j * tyo] = sum;
    }
  }
  return out;
};
export {
  mulM
};