Matrix multiplication: Difference between revisions

=={{header|Swift}}==

<lang swift>@inlinable

public func matrixMult<T: Numeric>(_ m1: [[T]], _ m2: [[T]]) -> [[T]] {

let n = m1[0].count

let m = m1.count

let p = m2[0].count

guard m != 0 else {

return [[]]

}

precondition(n == m2.count)

var ret = Array(repeating: Array(repeating: T.zero, count: p), count: m)

for i in 0..<m {

for j in 0..<p {

for k in 0..<n {

ret[i][j] += m1[i][k] * m2[k][j]

}

}

}

return ret

}

@inlinable

public func printMatrix<T>(_ matrix: [[T]]) {

guard !matrix.isEmpty else {

print()

return

}

let rows = matrix.count

let cols = matrix[0].count

for i in 0..<rows {

for j in 0..<cols {

print(matrix[i][j], terminator: " ")

}

print()

}

}

let m1 = [

[6.5, 2, 3],

[4.5, 1, 5]

]

let m2 = [

[10.0, 16, 23, 50],

[12, -8, 16, -4],

[70, 60, -1, -2]

]

let m3 = matrixMult(m1, m2)

printMatrix(m3)</lang>

{{out}}

<pre>299.0 268.0 178.5 311.0

407.0 364.0 114.5 211.0 </pre>