?? matrix.js
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/* Copyright (c) 2004-2006, The Dojo Foundation All Rights Reserved. Licensed under the Academic Free License version 2.1 or above OR the modified BSD license. For more information on Dojo licensing, see: http://dojotoolkit.org/community/licensing.shtml*/dojo.provide("dojo.math.matrix");//// some of this code is based on// http://www.mkaz.com/math/MatrixCalculator.java// (published under a BSD Open Source License)//// the rest is from my vague memory of matricies in school [cal]//// the copying of arguments is a little excessive, and could be trimmed back in// the case where a function doesn't modify them at all (but some do!)//dojo.math.matrix.iDF = 0;dojo.math.matrix.multiply = function(a, b){ a = dojo.math.matrix.copy(a); b = dojo.math.matrix.copy(b); var ax = a[0].length; var ay = a.length; var bx = b[0].length; var by = b.length; if (ax != by){ dojo.debug("Can't multiply matricies of sizes "+ax+','+ay+' and '+bx+','+by); return [[0]]; } var c = []; for(var k=0; k<ay; k++){ c[k] = []; for(var i=0; i<bx; i++){ c[k][i] = 0; for(var m=0; m<ax; m++){ c[k][i] += a[k][m]*b[m][i]; } } } return c;}dojo.math.matrix.inverse = function(a){ a = dojo.math.matrix.copy(a); // Formula used to Calculate Inverse: // inv(A) = 1/det(A) * adj(A) var tms = a.length; var m = dojo.math.matrix.create(tms, tms); var mm = dojo.math.matrix.adjoint(a); var det = dojo.math.matrix.determinant(a); var dd = 0; if (det == 0){ dojo.debug("Determinant Equals 0, Not Invertible."); return [[0]]; }else{ dd = 1 / det; } for (var i = 0; i < tms; i++) for (var j = 0; j < tms; j++) { m[i][j] = dd * mm[i][j]; } return m;}dojo.math.matrix.determinant = function(a){ a = dojo.math.matrix.copy(a); if (a.length != a[0].length){ dojo.debug("Can't calculate the determiant of a non-squre matrix!"); return 0; } var tms = a.length; var det = 1; var b = dojo.math.matrix.upperTriangle(a); for (var i=0; i < tms; i++){ det *= b[i][i]; } det = det * dojo.math.matrix.iDF; return det;}dojo.math.matrix.upperTriangle = function(m){ m = dojo.math.matrix.copy(m); var f1 = 0; var temp = 0; var tms = m.length; var v = 1; dojo.math.matrix.iDF = 1; for (var col = 0; col < tms - 1; col++) { for (var row = col + 1; row < tms; row++) { v = 1; var stop_loop = 0; // check if 0 in diagonal while ((m[col][col] == 0) && !stop_loop){ // if so switch until not if (col + v >= tms){ // check if switched all rows dojo.math.matrix.iDF = 0; stop_loop = 1; }else{ for (var c = 0; c < tms; c++) { temp = m[col][c]; m[col][c] = m[col + v][c]; // switch rows m[col + v][c] = temp; } v++; // count row switchs dojo.math.matrix.iDF *= -1; // each switch changes determinant factor } } if (m[col][col] != 0) { f1 = (-1) * m[row][col] / m[col][col]; for (var i = col; i < tms; i++) { m[row][i] = f1 * m[col][i] + m[row][i]; } } } } return m;}dojo.math.matrix.create = function(a, b){ var m = []; for(var i=0; i<b; i++){ m[i] = []; for(var j=0; j<a; j++){ m[i][j] = 0; } } return m;}dojo.math.matrix.adjoint = function(a){ a = dojo.math.matrix.copy(a); var tms = a.length; if (a.length != a[0].length){ dojo.debug("Can't find the adjoint of a non-square matrix"); return [[0]]; } if (tms == 1){ dojo.debug("Can't find the adjoint of a 1x1 matrix"); return [[0]]; } var m = dojo.math.matrix.create(tms, tms); var ii = 0; var jj = 0; var ia = 0; var ja = 0; var det = 0; for (var i = 0; i < tms; i++){ for (var j = 0; j < tms; j++){ ia = 0; ja = 0; var ap = dojo.math.matrix.create(tms-1, tms-1); for (ii = 0; ii < tms; ii++) { for (jj = 0; jj < tms; jj++) { if ((ii != i) && (jj != j)) { ap[ia][ja] = a[ii][jj]; ja++; } } if ((ii != i) && (jj != j)) { ia++; } ja = 0; } det = dojo.math.matrix.determinant(ap); m[i][j] = Math.pow(-1 , (i + j)) * det; } } m = dojo.math.matrix.transpose(m); return m;}dojo.math.matrix.transpose = function(a){ a = dojo.math.matrix.copy(a); var m = dojo.math.matrix.create(a.length, a[0].length); for (var i = 0; i < a.length; i++) for (var j = 0; j < a[i].length; j++) m[j][i] = a[i][j]; return m;}dojo.math.matrix.format = function(a){ function format_int(x){ var dp = 5; var fac = Math.pow(10 , dp); var a = Math.round(x*fac)/fac; var b = a.toString(); if (b.charAt(0) != '-'){ b = ' ' + b;} var has_dp = 0; for(var i=1; i<b.length; i++){ if (b.charAt(i) == '.'){ has_dp = 1; } } if (!has_dp){ b += '.'; } while(b.length < dp+3){ b += '0'; } return b; } var ya = a.length; var xa = a[0].length; var buffer = ''; for (var y=0; y<ya; y++){ buffer += '| '; for (var x=0; x<xa; x++){ buffer += format_int(a[y][x]) + ' '; } buffer += '|\n'; } return buffer;}dojo.math.matrix.copy = function(a){ var ya = a.length; var xa = a[0].length; var m = dojo.math.matrix.create(xa, ya); for (var y=0; y<ya; y++){ for (var x=0; x<xa; x++){ m[y][x] = a[y][x]; } } return m;}dojo.math.matrix.scale = function(k, a){ a = dojo.math.matrix.copy(a); var ya = a.length; var xa = a[0].length; for (var y=0; y<ya; y++){ for (var x=0; x<xa; x++){ a[y][x] *= k; } } return a;}
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