2c:null 2d:["$","title",null,{"children":"Map multiple pseudo broadcast | David | Observable"}] 32:T6b3,# Still not working - I think this is mostly working ```js const A = [1]; const B = [[10, 20], [30, 40]]; const sizes = [[1], [2, 2]]; const broadcastedSizes = [2, 2]; const offsets = sizes.map( size => broadcastedSizes.length - size.length ) const maxDepth = broadcastedSizes.length - 1; puts(map([A, B], add)); function map(arrays, fn) { const index = new Array(maxDepth + 1); return recurse(arrays); function recurse(arrs, depth = 0) { const result = []; if (depth === maxDepth) { for(let i = 0; i < broadcastedSizes[depth]; i++) { index[depth] = i; puts('index', index); result.push(fn(...arrs)); } } else { for(let i = 0; i < broadcastedSizes[depth]; i++) { index[depth] = i; result.push(recurse( arrs.map((arr, idx) => { const offset = offsets[idx]; const size = sizes[idx]; const relativeDepth = depth - offset; puts('relativeDepth', relativeDepth); puts('offset', offset); puts('size', size); if(relativeDepth < 0) { return arr; } if(size[relativeDepth] === 1) { return arr; } return arr[i]; }), depth + 1)); } } return result; } } function add(a, b) { return a + b; } function puts(...args) { console.log(...args); } ``` 33:T586,function mapMultipleMemoize(arrays, multiCallback) { // in each array in each dimension save the previous index and value // otherwise use get const newSize = broadcastedSizes; const maxDepth = newSize.length - 1; const sizes = arrays.map(array => math.size(array)); const buffers = arrays.map(()=>new Map()) const index = []; return recurse(); // maintain an array of buffers and offsets, then for each depth // find if the depth-offest has a matching index.toString() // and if so use it's value // start by using only one // use new Map get and set methods function getFromBuffer(arrayIndex, index){ const indexStr = index.toString() let result = buffers[arrayIndex].get(indexStr) if( result === undefined){ result = get(arrays[arrayIndex], index) buffers[arrayIndex].set(indexStr, result) } return result }; function recurse(depth = 0) { const result = []; if (depth < maxDepth) { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push(recurse(depth + 1)); } } else { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push( multiCallback( ...arrays.map((arr, idx) => getFromBuffer(idx, unbroadcastIndex(index, sizes[idx])) ) ) ); } } return result; } }34:T423, function mapMultipleIdeal(arrays, callback) { // const sizes = arrays.map(array => math.size(array)); const broadcastedSize = broadcastedSizes //broadcastSizes(...sizes); const maxDepth = broadcastedSize.length - 1; const offsets = sizes.map(size => maxDepth - size.length + 1); return recurse(arrays, 0); function recurse(values, depth) { const N = broadcastedSize[depth]; const relativeDepth = offsets.map(offset => depth - offset); const lengths = sizes.map((size, id) => relativeDepth[id] < 0 ? null : size[relativeDepth[id]]); const result = new Array(N); if (depth < maxDepth) { for (let i = 0; i < N; i++) { result[i] = recurse(values.map((value, id) => (relativeDepth[id] < 0 ? value : value[i])), depth + 1); } } else { for (let i = 0; i < N; i++) { result[i] = callback(...values.map((value, id) => (lengths[id] > 1 ? value[i] : value[0]))); } } return result; } } 35:T5a4,function mapMultipleMemoize1(arrays, multiCallback) { // in each array in each dimension save the previous index and value // otherwise use get const newSize = broadcastedSizes; const maxDepth = newSize.length - 1; const sizes = arrays.map(array => math.size(array)); const buffers = arrays.map(()=>({})) const index = []; return recurse(); // maintain an array of buffers and offsets, then for each depth // find if the depth-offest has a matching index.toString() // only keep a simple buffer function getFromBuffer(arrayIndex, index){ const indexStr = index.toString() const previous = buffers[arrayIndex] let result if (previous.value === undefined || previous.index !== indexStr){ result = get(arrays[arrayIndex], index) buffers[arrayIndex] = {index:indexStr, value: result} } else { result = previous.value } return result }; function recurse(depth = 0) { const result = []; if (depth < maxDepth) { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push(recurse(depth + 1)); } } else { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push( multiCallback( ...arrays.map((arr, idx) => getFromBuffer(idx, unbroadcastIndex(index, sizes[idx])) ) ) ); } } return result; } }36:T48f,function mapMultipleNoGet(arrays, multiCallback) { // this will attempt to only pass section of each array without broadcasting them according to the needs const newSize = broadcastedSizes; // Determine the broadcasted size const maxDepth = newSize.length - 1; const index = Array(maxDepth + 1).fill(0); // Initialize the index array return recurse(arrays); function recurse(values, depth = 0) { const result = []; const bcSize = broadcastedSizes.slice(depth); const sizes = values.map((value) => math.size(value)); const offsets = sizes.map((size) => bcSize.length - size.length); if (depth < maxDepth) { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push( recurse( values.map((value, idx) => { const thisOffset = offsets[idx]; return thisOffset > 0 ? value : value[i] }), depth + 1 ) ); } } else { for (let i = 0; i < newSize[depth]; i++) { index[depth] = i; result.push(multiCallback(...values)); } } console.log(result); return result; } }37:[] 30:{"id":"1b7e66a4c81f4615","slug":"map_mutiple","title":"Map multiple pseudo broadcast","thumbnail":"83ebc415c5bf2ef94530b691f4e343decf8e8160f35cc0025b45e5e6a7a63d84","access_level":"public","create_time":"$D2025-03-10T16:48:08.820Z","update_time":"$D2025-03-26T02:06:18.816Z","view_time":null,"first_public_time":"$D2025-03-25T21:09:48.021Z","has_unpublished_edits":null,"fork":{"id":"64404e368be02d9e","slug":"super-map","title":"Super map","owner":{"id":"cd42f0d98191a7df","login":"dvd101x","name":"David"}},"stars":0,"starred":false,"owner":{"type":"team","id":"cd42f0d98191a7df","login":"dvd101x","name":"David","avatar_url":"https://avatars-next.observableusercontent.com/665b28399b8c69493837e25bfd6b1e60e5c83f5f646e274cf39b5146449e30c6","tier":"starter_2024"},"version":1258,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"c454621e13d910d3","login":"dvd101x","name":"David","avatar_url":"https://avatars-next.observableusercontent.com/665b28399b8c69493837e25bfd6b1e60e5c83f5f646e274cf39b5146449e30c6","tier":null}],"members":[{"type":"individual","id":"c454621e13d910d3","login":"dvd101x","name":"David","avatar_url":"https://avatars-next.observableusercontent.com/665b28399b8c69493837e25bfd6b1e60e5c83f5f646e274cf39b5146449e30c6","tier":null,"role":"editor"},{"type":"team","id":"cd42f0d98191a7df","login":"dvd101x","name":"David","avatar_url":"https://avatars-next.observableusercontent.com/665b28399b8c69493837e25bfd6b1e60e5c83f5f646e274cf39b5146449e30c6","tier":"starter_2024","role":"viewer"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Map multiple pseudo broadcast","cells":[{"id":0,"value":"# Map multiple pseudo broadcast\n\nThe intention is to use fake indices to make map multiple faster.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":29,"value":"result = table(stats, numWarmups, numTrials, numRepeats)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":873,"value":"The main idea is to use a broadcasted index and then convert it to an index for each part.\n\n```\nA = [[1],[2]]\nB = [[3, 4]]\n```","pinned":true,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":15,"value":"viewof reRun = {\n const button = html`