99 lines
2.9 KiB
Markdown
99 lines
2.9 KiB
Markdown
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---
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title: Matrix Calculator
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localeTitle: 矩阵计算器
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---
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## 矩阵计算器
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矩阵计算器用于执行加法，减法或乘法。 另外，它可以执行特定于矩阵的操作，例如矩阵转置，反转或定义矩阵的等级。
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Matrix由行和列（nxm）构建。在矩阵上完成的操作通常会对矩阵的维度施加一些限制。
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##### 加成：
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通过添加两个**相同**尺寸的矩阵的值来完成添加。 结果是一个与原始数组尺寸相同的数组。
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```javascript
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// matrices a and b are represented by an array of arrays (rows of columns)
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function addMatrices(a, b) {
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// we might want to add here constraints for the same dimensions
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if (!Array.isArray(a) || !Array.isArray(a[0]) || !Array.isArray(b) || !Array.isArray(b[0])) {
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throw new Error('a, b or it\'s children is not an array');
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}
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const result = [];
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for (let i = 0; i < a.length; i++) {
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result[i] = [];
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for (let j = 0; j < a[i].length; j++) {
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result[i][j] = a[i][j] + b[i][j];
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}
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}
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return result;
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}
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```
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##### 减法：
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通过减去**相同**维度的两个矩阵的值来完成减法。 结果是一个与原始数组尺寸相同的数组。
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```javascript
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// matrices a and b are represented by an array of arrays (rows of columns)
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function subtractMatrices(a, b) {
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// we might want to add here constraints for the same dimensions
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if (!Array.isArray(a) || !Array.isArray(a[0]) || !Array.isArray(b) || !Array.isArray(b[0])) {
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throw new Error('a, b or it\'s children is not an array');
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}
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const result = [];
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for (let i = 0; i < a.length; i++) {
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result[i] = [];
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for (let j = 0; j < a[i].length; j++) {
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result[i][j] = a[i][j] - b[i][j];
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}
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}
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return result;
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}
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```
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##### 乘法：
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乘法可以通过将矩阵乘以标量或乘以矩阵来完成。 如果我们乘以两个矩阵，只有当左矩阵中的列数等于右矩阵中的行数时才能进行。
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```javascript
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// matrices a and b are represented by an array of arrays (rows of columns)
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function multiplyMatrices(a, b) {
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// we might want to add here constraints for the dimensions
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//let's assume that b has to be either a scalar or an array
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if (!Array.isArray(a) || !Array.isArray(a[0]) || ((!Array.isArray(b) || !Array.isArray(b[0])) && isNaN(b))) {
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throw new Error('a, b or it\'s children is not an array');
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}
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if (!isNaN(b)) {
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for (let i = 0; i < a.length; i++) {
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for (let j = 0; j < a[i].length; j++) {
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a[i][j] = a[i][j] * b;
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}
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}
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return a;
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}
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const result = [];
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for (let i = 0; i < a.length; i++) {
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result[i] = [];
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for (let j = 0; j < a[i].length; j++) {
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let sum = 0;
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for (let k = 0; k < b[i].length; k++) {
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sum += a[i][k] * b[k][j];
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}
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result[i][j] = sum;
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}
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}
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return result;
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}
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```
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#### 更多信息：
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https://en.wikipedia.org/wiki/Matrix\_(mathematics）
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