Lu decomposition, JavaScript code

A is a matrix, written here as a one-dimensional array, such as "1", "1,2,3,4" function Getlu (a) {var n = a.length;//Matrix total data number var s = math.sqrt (n);//The Order of the matrix var L = new Arra Y (n), var U = new Array (n), if (Getdet (a)! = 0) {var Allordernotequleszero = true;for (var i = 0; i < s; i++) {if (Getdet (G        Etordermatrix (A, i)) = = 0) {Allordernotequleszero = False;break;}} if (Allordernotequleszero) {for (var i = 0, i < s; i++) {for (var j = 0; J < S; j + +) {if (i = = j) {l[i*s + j] = 1;}            else if (I < j) {L[i*s+j] = 0;}            if (i > J) u[i*s+j] = 0;            U[0*S+J] = A[0*s+j]; L[I*S+0] = a[i*s+0]/u[0*s+0];}}            for (var k = 1, k < S; k++) {for (var j = k; J < S; j + +) {tmp = 0;            for (var m = 0; m < K; m++) {tmp + = l[k*s+m] * U[m*s+j];        } U[k*s+j] = a[k*s+j]-tmp;            } for (var i = k+1; i < S; i++) {tmp = 0;           for (var m = 0; m < K; m++) {     TMP + = l[i*s+m] * U[m*s+k];        } L[i*s+k] = (a[i*s+k]-tmp)/u[k*s+k]; }}}else {alert (' The matrix has 0 in the order of the master style!  ') Console.log (Getlastmatrix (a)), for (var i = 0, i < s; i++) {for (var j = 0; J < S; j + +) {if (J > i) {u[i * s + j] = A[i * s + j]; L[i * s + j] = 0;} else if (j = = i) {U[i * s + j] = A[i * s + j]; L[i * s + j] = 1;} Else{l[i * s + j] = A[i * s + j]; U[i * s + j] = 0;}}} Console.log (L); Console.log (U);} Else{alert (' The matrix is a singular matrix and cannot be decomposed by Lu! ‘);}} function Getdet (a) {var n = total data of a.length;//matrix var s = math.sqrt (n);//The Order of the matrix var sum = 0;if (n = = 1) {return a[0];} for (var i = 0; i < s; i++) {if (i 2 = = 0) {sum + = a[i] * Getdet (Getsubmatrix (A, i))}else{sum-= a[i] * Getdet (GETSUBMA Trix (A, i))}}return sum;}  Gets the number of matrix function Getlastmatrix (a) {var n = a.length;//Matrix after the nth column is compared var s = math.sqrt (n);//The Order of the matrix var p = [];for (var i = 0; I < S; i++) {for (var j = 0; J < S; j + +) {if (i = = j) {P.push (1);} else {p.push (0);}}} for (var i = 0; i < s-1; i++) {a = Getnewmatrix (A, I, p); }console.log (P); return A;} function Getnewmatrix (A, K, p) {var n = Total data number of a.length;//matrix var s = math.sqrt (n);//order of matrix var result = [];var Maxrownum = 0;va R MAXValue = Math.Abs (a[k * s + K]); for (var i = 1; i < S; i++) {if (i >= k && math.abs (A[i * s + K]) > MAXValue) {maxrownum = i; MAXValue = Math.Abs (A[i * s + K]);}} Console.log (' maxrownum: ' + maxrownum);//console.log (' MAXValue: ' + MAXValue '); if (maxrownum! = k) {for (var i = 0; I < s ; i++) {var temp = A[k * s + i];a[k * s + i] = A[maxrownum * s + i]a[maxrownum * s + i] = Temp;var TMP1 = p[k * s + i];p [k * S + i] = P[maxrownum * s + i]p[maxrownum * s + i] = TMP1;} Console.log (a);//console.log (P); if (MAXValue! = 0) {for (var i = k + 1; i < S; i++) {if (A[i * s + K]! = 0) {A[i * s + k ] = parsefloat (A[i * s + K]/a[k * s + K]) for (var j = k + 1; j< s; j + +) {A[i * s + j] = parsefloat (A[i * s + j]-A[i * s + K] * A[k * s + j])}}}}}else{if (MAXValue! = 0) {for (var i = k + 1; i < S; i++) {if (A[i * s + K]! = 0) {a[I * s + K] = parsefloat (A[i * s + K]/a[k * s + k)) for (var j = k + 1; j< s; j + +) {A[i * s + j] = parsefloat (A[K * s + J]-A[i * s + K] * A[i * s + j])}}}}}//console.log (a); return A; A is the original matrix, K is the number of columns in the function Getsubmatrix (A, k) {var n = Total data of the a.length;//matrix var s = math.sqrt (n);//The Order of the Matrix var = []; for ( var i = 1; I < S; i++) {for (var j = 0; J < S; j + +) {if (k! = j) {Result.push (a[i*s +j]);}} return result;} Get the Order Master matrix, K for order function Getordermatrix (A, k) {var n = a.length;//Matrix total data number var s = math.sqrt (n);//The Order of the Matrix var = []; f or (var i = 0; i < s; i++) {for (var j = 0; J < S; j + +) {if (I <= k && J <= k) {Result.push (a[i*s +j]);} }}return result;}

　　

Lu decomposition, JavaScript code