Kronecker product: Difference between revisions

</pre>

=={{header|Scala}}==

<lang scala> object KroneckerProduct

{

def getDimensions(matrix : Array[Array[Int]]) : (Int,Int) = {

val dimensions = matrix.map(x => x.size)

(dimensions.size, dimensions(0))

}

def kroneckerProduct(matrix1 : Array[Array[Int]], matrix2 : Array[Array[Int]]) : Array[Array[Int]] = {

val (r1,c1) = getDimensions(matrix1)

val (r2,c2) = getDimensions(matrix2)

val res = Array.ofDim[Int](r1*r2, c1*c2)

for(

i <- 0 until r1;

j <- 0 until c1;

k <- 0 until r2;

l <- 0 until c2

){

res(r2 * i + k)(c2 * j + l) = matrix1(i)(j) * matrix2(k)(l)

}

res

}

def main(args: Array[String]): Unit = {

val m1 = Array(Array(1, 2), Array(3, 4))

val m2 = Array(Array(0, 5), Array(6, 7))

println(kroneckerProduct(m1,m2).map(_.mkString("|")).mkString("\n"))

println("----------")

val m3 = Array(Array(0, 1, 0), Array(1, 1, 1), Array(0, 1, 0))

val m4 = Array(Array(1, 1, 1, 1), Array(1, 0, 0, 1), Array(1, 1, 1, 1))

println(kroneckerProduct(m3,m4).map(_.mkString("|")).mkString("\n"))

}

}

</lang>

{{out}}

<pre>

0|5|0|10

6|7|12|14

0|15|0|20

18|21|24|28

----------

0|0|0|0|1|1|1|1|0|0|0|0

0|0|0|0|1|0|0|1|0|0|0|0

0|0|0|0|1|1|1|1|0|0|0|0

1|1|1|1|1|1|1|1|1|1|1|1

1|0|0|1|1|0|0|1|1|0|0|1

1|1|1|1|1|1|1|1|1|1|1|1

0|0|0|0|1|1|1|1|0|0|0|0

0|0|0|0|1|0|0|1|0|0|0|0

0|0|0|0|1|1|1|1|0|0|0|0