add functions for appending vector to matrix in columns and rows

Author: jbytecode

src/main/scala/matrix.scala

@@ -94,6 +94,10 @@ object Matrix:
 
   def size(a: Mat): (Int, Int) = (a.length, a(0).length)
 
+  def appendColumnVec(a: Mat, b: Vec): Mat = a :+ b
+
+  def appendRowVec(a: Mat, b: Vec): Mat = (a.transpose :+ b).transpose
+
   def euclideanDistance(a: Vec, b: Vec): Double =
     math.sqrt(a.zip(b).map((x, y) => (x - y) * (x - y)).sum)
 

src/test/scala/testmatrix.scala

@@ -217,4 +217,18 @@ class TestMatrix extends munit.FunSuite {
     val expected = Array(1.0 + 2.0 + 3.0 + 4.0, 4.0 + 5.0 + 6.0 + 7.0, 7.0 + 8.0 + 9.0 + 10.0)
     A.assert(Matrix.elementwise_equal(result, expected))
   }
+  test("Append a Column Vector to Matrix"){
+    val mat = Array(Array(1.0, 2.0, 3.0), Array(4.0, 5.0, 6.0), Array(7.0, 8.0, 9.0))
+    val col = Array(10.0, 11.0, 12.0)
+    val newmat = Matrix.appendcol(mat, col)
+    val expected = Array(Array(1.0, 2.0, 3.0, 10.0), Array(4.0, 5.0, 6.0, 11.0), Array(7.0, 8.0, 9.0, 12.0))
+    A.assert(Matrix.elementwise_equal(newmat, expected, 1e-6))
+  }
+  test("Append a Row Vector to Matrix"){
+    val mat = Array(Array(1.0, 2.0, 3.0), Array(4.0, 5.0, 6.0))
+    val row = Array(7.0, 8.0, 9.0)
+    val newmat = Matrix.appendrow(mat, row)
+    val expected = Array(Array(1.0, 2.0, 3.0), Array(4.0, 5.0, 6.0), Array(7.0, 8.0, 9.0))
+    A.assert(Matrix.elementwise_equal(newmat, expected, 1e-6))
+  }
 }