From 479dde385222e6dafb50d143c3f52482973df857 Mon Sep 17 00:00:00 2001
From: Simon Parten <quafadas@gmail.com>
Date: Thu, 12 Sep 2024 23:17:49 +0200
Subject: [PATCH] transpose

---
 vecxt/src/package.scala             | 23 +++++++++++++++++++++++
 vecxt/test/src/TensorExt.test.scala | 16 ++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/vecxt/src/package.scala b/vecxt/src/package.scala
index 79db1c4..0dea622 100644
--- a/vecxt/src/package.scala
+++ b/vecxt/src/package.scala
@@ -69,7 +69,9 @@ object Tensors:
 
   extension (m: Matrix)
     inline def rows: Int = m._2._1
+
     inline def cols: Int = m._2._2
+
     inline def row(i: Int): NArray[Double] =
       val start = i * m.cols
       val end = (i + 1) * m.cols
@@ -83,6 +85,27 @@ object Tensors:
       end while
       result
     end row
+
+    inline def print: String =
+      val arrArr = for i <- 0 until m.rows yield m.row(i).mkString(" ")
+      arrArr.mkString("\n")
+    end print
+
     inline def col(i: Int): NArray[Double] = NArray.tabulate(m.rows)(j => m._1(j * m.cols + i))
+
+    inline def transpose: Matrix =
+      val newArr = NArray.ofSize[Double](m._1.length)
+      var i = 0
+      while i < m.cols do
+        var j = 0
+        while j < m.rows do
+          newArr(i * m.rows + j) = m._1(j * m.cols + i)
+          j += 1
+        end while
+        i += 1
+      end while
+      Matrix(newArr, (m.cols, m.rows))
+    end transpose
   end extension
+
 end Tensors
diff --git a/vecxt/test/src/TensorExt.test.scala b/vecxt/test/src/TensorExt.test.scala
index aae3876..44a51f5 100644
--- a/vecxt/test/src/TensorExt.test.scala
+++ b/vecxt/test/src/TensorExt.test.scala
@@ -24,6 +24,22 @@ class TensorExtensionSuite extends FunSuite:
     assertVecEquals(result.raw, NArray(58.0, 139.0, 64.0, 154.0))
   }
 
+  test("Matrix transpose") {
+    val originalArray = NArray[Double](1, 2, 3, 4, 5, 6)
+    val matrix = Matrix(originalArray, (2, 3))
+
+    println(matrix.print)
+
+    val transposedMatrix = matrix.transpose
+
+    val expectedArray = NArray[Double](1, 4, 2, 5, 3, 6)
+    val expectedMatrix = Matrix(expectedArray, (3, 2))
+
+    assertEquals(transposedMatrix.raw.toList, expectedMatrix.raw.toList)
+    assertEquals(transposedMatrix.rows, expectedMatrix.rows)
+    assertEquals(transposedMatrix.cols, expectedMatrix.cols)
+  }
+
   test("Tensor raw array retrieval") {
     val vec = Vector(NArray[Double](1.0, 2.0, 3.0))
     assertVecEquals(vec.raw, NArray(1.0, 2.0, 3.0))