Merge pull request #21 from lazarospsa/HoldingPeriodReturn-#16

HoldingPeriodReturn #16

gofin.go

@@ -72,6 +72,17 @@ func PresentValueAnnuity(interestRate float64, periods int, cashFlows []float64)
 	return presentValueAnnuity
 }
 
+// HoldingPeriodReturn calculates the holding period return (HPR)
+func HoldingPeriodReturn(initialValue, finalValue float64) float64 {
+	return (finalValue - initialValue) / initialValue
+}
+
+// HoldingPeriodReturn calculates the holding period return (HPR)
+// as a percentage
+func HoldingPeriodReturnPercentage(initialValue, finalValue float64) float64 {
+	return ((finalValue - initialValue) / initialValue)*100
+}
+
 func PresentValueAnnuityDue(interestRate float64, periods int, cashFlows []float64) float64 {
 	presentValueAnnuityDue := 0.0
 	for i := 0; i < len(cashFlows); i++ {

gofin_test.go

@@ -64,6 +64,32 @@ func TestPresentValuePerpetuity(t *testing.T) {
 	}
 }
 
+func TestHoldingPeriodReturn(t *testing.T) {
+	var initialValue float64 = 1000.0
+	var finalValue float64 = 1200.0
+	var expected float64 = 0.20
+
+	actual := HoldingPeriodReturn(initialValue, finalValue)
+
+	if compareFloat64(actual, expected) {
+		t.Errorf("Test failed, expected: '%f', got: '%f'", expected, actual)
+	}
+}
+
+
+func TestHoldingPeriodReturnPercentage(t *testing.T) {
+	var initialValue float64 = 1000.0
+	var finalValue float64 = 1200.0
+	var expected float64 = 20.0
+
+	actual := HoldingPeriodReturn(initialValue, finalValue)
+
+	if compareFloat64(actual, expected) {
+		t.Errorf("Test failed, expected: '%f', got: '%f'", expected, actual)
+	}
+}
+
+
 func TestFutureValueAnnuity(t *testing.T) {
 	var payment float64 = 100
 	var interestRate float64 = 0.1