Element-wise operations: Difference between revisions

=={{header|Kotlin}}==

<lang scala>// version 1.1.51

typealias Matrix = Array<DoubleArray>

typealias Op = Double.(Double) -> Double

fun Double.dPow(exp: Double) = Math.pow(this, exp)

fun Matrix.elementwiseOp(other: Matrix, op: Op): Matrix {

require(this.size == other.size && this[0].size == other[0].size)

val result = Array(this.size) { DoubleArray(this[0].size) }

for (i in 0 until this.size) {

for (j in 0 until this[0].size) result[i][j] = this[i][j].op(other[i][j])

}

return result

}

fun Matrix.elementwiseOp(d: Double, op: Op): Matrix {

val result = Array(this.size) { DoubleArray(this[0].size) }

for (i in 0 until this.size) {

for (j in 0 until this[0].size) result[i][j] = this[i][j].op(d)

}

return result

}

fun Matrix.print(name: Char?, scalar: Boolean? = false) {

println(when (scalar) {

true -> "m $name s"

false -> "m $name m"

else -> "m"

} + ":")

for (i in 0 until this.size) println(this[i].asList())

println()

}

fun main(args: Array<String>) {

val ops = listOf(Double::plus, Double::minus, Double::times, Double::div, Double::dPow)

val names = "+-*/^"

val m = arrayOf(

doubleArrayOf(3.0, 5.0, 7.0),

doubleArrayOf(1.0, 2.0, 3.0),

doubleArrayOf(2.0, 4.0, 6.0)

)

m.print(null, null)

for ((i, op) in ops.withIndex()) m.elementwiseOp(m, op).print(names[i])

val s = 2.0

println("s = $s:\n")

for ((i, op) in ops.withIndex()) m.elementwiseOp(s, op).print(names[i], true)

}</lang>

{{out}}

<pre>

m:

[3.0, 5.0, 7.0]

[1.0, 2.0, 3.0]

[2.0, 4.0, 6.0]

m + m:

[6.0, 10.0, 14.0]

[2.0, 4.0, 6.0]

[4.0, 8.0, 12.0]

m - m:

[0.0, 0.0, 0.0]

[0.0, 0.0, 0.0]

[0.0, 0.0, 0.0]

m * m:

[9.0, 25.0, 49.0]

[1.0, 4.0, 9.0]

[4.0, 16.0, 36.0]

m / m:

[1.0, 1.0, 1.0]

[1.0, 1.0, 1.0]

[1.0, 1.0, 1.0]

m ^ m:

[27.0, 3125.0, 823543.0]

[1.0, 4.0, 27.0]

[4.0, 256.0, 46656.0]

s = 2.0:

m + s:

[5.0, 7.0, 9.0]

[3.0, 4.0, 5.0]

[4.0, 6.0, 8.0]

m - s:

[1.0, 3.0, 5.0]

[-1.0, 0.0, 1.0]

[0.0, 2.0, 4.0]

m * s:

[6.0, 10.0, 14.0]

[2.0, 4.0, 6.0]

[4.0, 8.0, 12.0]

m / s:

[1.5, 2.5, 3.5]

[0.5, 1.0, 1.5]

[1.0, 2.0, 3.0]

m ^ s:

[9.0, 25.0, 49.0]

[1.0, 4.0, 9.0]

[4.0, 16.0, 36.0]

</pre>