Implement composed2 and composed3 functions

Author: rsdc2

QSharpMathUtils/src/HigherOrderFunctions.qs

@@ -1,5 +1,13 @@
 namespace HigherOrderFunctions {
 
+    function Composed2<'T, 'U, 'V>(f1 : 'U -> 'V, f2 : 'T -> 'U) : ('T -> 'V) {
+        x -> f1(f2(x))
+    } 
+
+    function Composed3<'T, 'U, 'V, 'W>(f1 : 'V -> 'W, f2 : 'U -> 'V, f3 : 'T -> 'U) : ('T -> 'W) {
+        x -> f1(f2(f3(x)))
+    }
+
     function Curry2<'T, 'U, 'V>(f : ('T, 'U) -> 'V) : ('T -> 'U -> 'V) {
         x -> y -> f(x, y)
     }
@@ -16,6 +24,6 @@ namespace HigherOrderFunctions {
         y -> x -> f(x)(y)
     }
 
-    export Curry2, Curry3, Flip2, Flip2_;
+    export Composed2, Composed3, Curry2, Curry3, Flip2, Flip2_;
 
 }

QSharpMathUtils/src/Main.qs

@@ -11,13 +11,15 @@ import Matrices.Identity.*;
 import Matrices.Multiply.*;
 import Complex.*;
 import Categories.Monoid.*;
+import HigherOrderFunctions.*;
 
 @EntryPoint()
-function Main() :   Double[][] {
+function Main() : Int {
+    let add : (Int, Int) -> Int = (x, y) -> x + y;
+    let mul3 : Int -> Int = x -> x * 3;
 
-    let matrix = [[1., 2.], [3., 4.]];
-    let matrix2 = [[-1., 3./2.], [1., -1.]];
-    MatMulD(matrix2, Invert2x2D(matrix2))
+    let f = Composed2(add(1, _), mul3);
+    f(1)
 
 }
 

tests/utilities/test_higher_order_functions.py

@@ -0,0 +1,74 @@
+import qsharp # type: ignore
+from .setup import init_qsharp
+
+init_qsharp()
+
+def test_compose2_normal():
+    # Arrange
+    qscode = ("import Std.Math.*;"
+             "import HigherOrderFunctions.*;"
+             "let add1 : Int -> Int = x -> x + 1;"
+             "let mul3 : Int -> Int = x -> x * 3;"
+             "Composed2(add1, mul3)(1)")
+
+    # Act
+    result = qsharp.eval(qscode)
+
+    # Assert
+    assert result == 4
+
+
+def test_compose2_partial():
+    # Arrange
+    qscode = ("import Std.Math.*;"
+             "import HigherOrderFunctions.*;"
+             "let add : (Int, Int) -> Int = (x, y) -> x + y;"
+             "let mul3 : Int -> Int = x -> x * 3;"
+             "Composed2(add(1, _), mul3)(1)")
+
+    # Act
+    result = qsharp.eval(qscode)
+
+    # Assert
+    assert result == 4
+
+
+def test_compose3_normal():
+    # Arrange
+    qscode = ("import Std.Math.*;"
+             "import HigherOrderFunctions.*;"
+             "let add1 : Int -> Int = x -> x + 1;"
+             "let mul3 : Int -> Int = x -> x * 3;"
+             "let minus1 : Int -> Int = x -> x - 1;"
+             "Composed3(minus1, add1, mul3)(1)")
+
+    # Act
+    result = qsharp.eval(qscode)
+
+    # Assert
+    assert result == 3
+
+
+def test_complex_equal_sad():
+    # Arrange
+    qscode = ("import Std.Math.*;"
+             "import Complex.*;"
+             "EqualC(Complex(1., 0.), Complex(1., 1.));")
+
+    # Act
+    result = qsharp.eval(qscode)
+
+    # Assert
+    assert result == False
+
+
+def test_to_complex():
+    # Arrange
+    qscode = ("import Complex.*;"
+              "ToC(1.3)")
+    
+    # Act
+    result = qsharp.eval(qscode)
+
+    # Assert
+    assert result == (1.3, 0.0)