60 lines
1.7 KiB
JavaScript
60 lines
1.7 KiB
JavaScript
/**
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* Keeps entries in the matrix when the callback function returns true, removes the entry otherwise
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*
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* @param {Matrix} a The sparse matrix
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* @param {function} callback The callback function, function will be invoked with the following args:
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* - The entry row
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* - The entry column
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* - The entry value
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* - The state parameter
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* @param {any} other The state
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*
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* @return The number of nonzero elements in the matrix
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*
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* Reference: http://faculty.cse.tamu.edu/davis/publications.html
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*/
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export function csFkeep(a, callback, other) {
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// a arrays
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var avalues = a._values;
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var aindex = a._index;
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var aptr = a._ptr;
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var asize = a._size; // columns
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var n = asize[1]; // nonzero items
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var nz = 0; // loop columns
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for (var j = 0; j < n; j++) {
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// get current location of col j
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var p = aptr[j]; // record new location of col j
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aptr[j] = nz;
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for (; p < aptr[j + 1]; p++) {
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// check we need to keep this item
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if (callback(aindex[p], j, avalues ? avalues[p] : 1, other)) {
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// keep A(i,j)
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aindex[nz] = aindex[p]; // check we need to process values (pattern only)
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if (avalues) {
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avalues[nz] = avalues[p];
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} // increment nonzero items
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nz++;
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}
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}
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} // finalize A
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aptr[n] = nz; // trim arrays
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aindex.splice(nz, aindex.length - nz); // check we need to process values (pattern only)
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if (avalues) {
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avalues.splice(nz, avalues.length - nz);
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} // return number of nonzero items
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return nz;
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} |