在JavaScript中将两个不同维度的矩阵相乘
我们需要编写一个JavaScript函数，该函数接受两个数字的二维数组并返回其矩阵乘法结果。
假设以下是我们的两个矩阵-
//5x4- let a = [ [1, 2, 3, 1], [4, 5, 6, 1], [7, 8, 9, 1], [1, 1, 1, 1], [5, 7, 2, 6] ]; //4x6- let b = [ [1, 4, 7, 3, 4, 6], [2, 5, 8, 7, 3, 2], [3, 6, 9, 6, 7, 8], [1, 1, 1, 2, 3, 6] ];
示例
让我们为该函数编写代码-
const multiplyMatrices = (a, b) => {
if (!Array.isArray(a) || !Array.isArray(b) || !a.length || !b.length) {
throw new Error('arguments should be in 2-dimensional array format');
}
let x = a.length,
z = a[0].length,
y = b[0].length;
if (b.length !== z) {
// XxZ & ZxY => XxY
throw new Error('number of columns in the first matrix should be the same as the number of rows in the second');
}
let productRow = Array.apply(null, new
Array(y)).map(Number.prototype.valueOf, 0);
let product = new Array(x);
for (let p = 0; p < x; p++) {
product[p] = productRow.slice();
}
for (let i = 0; i < x; i++) {
for (let j = 0; j < y; j++) {
for (let k = 0; k < z; k++) {
product[i][j] += a[i][k] * b[k][j];
}
}
}
return product;
}
//5x4-
let a = [
[1, 2, 3, 1],
[4, 5, 6, 1],
[7, 8, 9, 1],
[1, 1, 1, 1],
[5, 7, 2, 6]
];
//4x6-
let b = [
[1, 4, 7, 3, 4, 6],
[2, 5, 8, 7, 3, 2],
[3, 6, 9, 6, 7, 8],
[1, 1, 1, 2, 3, 6]
];
//应产生5x6矩阵
console.log(multiplyMatrices(a, b));输出结果
控制台中的输出：-
[ [ 15, 33, 51, 37, 34, 40 ], [ 33, 78, 123, 85, 76, 88 ], [ 51, 123, 195, 133, 118, 136 ], [ 7, 16, 25, 18, 17, 22 ], [ 31, 73, 115, 88, 73, 96 ] ]