> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/m/matrix_multiplication.md).

# Matrix multiplication

```ruby
func matrix_multi(a, b) {
    var m = [[]]
    for r in ^a {
        for c in ^b[0] {
            for i in ^b {
                m[r][c] := 0 += (a[r][i] * b[i][c])
            }
        }
    }
    return m
}
 
var a = [
          [1, 2],
          [3, 4],
          [5, 6],
          [7, 8]
        ]
 
var b = [
          [1, 2, 3],
          [4, 5, 6]
        ]
 
for line in matrix_multi(a, b) {
    say line.map{|i|'%3d' % i }.join(', ')
}
```

#### Output:

```
  9,  12,  15
 19,  26,  33
 29,  40,  51
 39,  54,  69
```