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- import IllegalArgumentException from '../../../../java/lang/IllegalArgumentException'
- export default class Matrix {
- static solve(a, b) {
- const n = b.length
- if (a.length !== n || a[0].length !== n) throw new IllegalArgumentException('Matrix A is incorrectly sized')
- for (let i = 0; i < n; i++) {
- let maxElementRow = i
- for (let j = i + 1; j < n; j++) if (Math.abs(a[j][i]) > Math.abs(a[maxElementRow][i])) maxElementRow = j
- if (a[maxElementRow][i] === 0.0) return null
- Matrix.swapRows(a, i, maxElementRow)
- Matrix.swapRows(b, i, maxElementRow)
- for (let j = i + 1; j < n; j++) {
- const rowFactor = a[j][i] / a[i][i]
- for (let k = n - 1; k >= i; k--) a[j][k] -= a[i][k] * rowFactor
- b[j] -= b[i] * rowFactor
- }
- }
- const solution = new Array(n).fill(null)
- for (let j = n - 1; j >= 0; j--) {
- let t = 0.0
- for (let k = j + 1; k < n; k++) t += a[j][k] * solution[k]
- solution[j] = (b[j] - t) / a[j][j]
- }
- return solution
- }
- static swapRows() {
- if (Number.isInteger(arguments[2]) && (arguments[0] instanceof Array && Number.isInteger(arguments[1]))) {
- const m = arguments[0], i = arguments[1], j = arguments[2]
- if (i === j) return null
- for (let col = 0; col < m[0].length; col++) {
- const temp = m[i][col]
- m[i][col] = m[j][col]
- m[j][col] = temp
- }
- } else if (Number.isInteger(arguments[2]) && (arguments[0] instanceof Array && Number.isInteger(arguments[1]))) {
- const m = arguments[0], i = arguments[1], j = arguments[2]
- if (i === j) return null
- const temp = m[i]
- m[i] = m[j]
- m[j] = temp
- }
- }
- }
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