From 18458bbc1c68e046ba27041e67a95c37929285f5 Mon Sep 17 00:00:00 2001
From: Lazaros Psarokostas <lazarospsa@hotmail.com>
Date: Mon, 18 Dec 2023 19:54:30 +0200
Subject: [PATCH] HoldingPeriodReturnAnnualized #17

---
 gofin.go      | 13 +++++++++++++
 gofin_test.go | 26 +++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/gofin.go b/gofin.go
index 466f6ea..b099beb 100644
--- a/gofin.go
+++ b/gofin.go
@@ -83,6 +83,19 @@ func HoldingPeriodReturnPercentage(initialValue, finalValue float64) float64 {
 	return ((finalValue - initialValue) / initialValue)*100
 }
 
+// HoldingPeriodReturnAnnualized calculates the annualized holding period return (HPR)
+func HoldingPeriodReturnAnnualized(initialValue, finalValue float64, holdingPeriodInYears float64) float64 {
+	hpr := HoldingPeriodReturn(initialValue, finalValue)
+	return math.Pow(1+hpr, 1/holdingPeriodInYears) - 1
+}
+
+// HoldingPeriodReturnAnnualized calculates the annualized holding period return (HPR)
+// as a percentage
+func HoldingPeriodReturnAnnualizedPercentage(initialValue, finalValue float64, holdingPeriodInYears float64) float64 {
+	hpr := HoldingPeriodReturn(initialValue, finalValue)
+	return (math.Pow(1+hpr, 1/holdingPeriodInYears) - 1)*100
+}
+
 func PresentValueAnnuityDue(interestRate float64, periods int, cashFlows []float64) float64 {
 	presentValueAnnuityDue := 0.0
 	for i := 0; i < len(cashFlows); i++ {
diff --git a/gofin_test.go b/gofin_test.go
index 0c29bd0..5278649 100644
--- a/gofin_test.go
+++ b/gofin_test.go
@@ -76,7 +76,6 @@ func TestHoldingPeriodReturn(t *testing.T) {
 	}
 }
 
-
 func TestHoldingPeriodReturnPercentage(t *testing.T) {
 	var initialValue float64 = 1000.0
 	var finalValue float64 = 1200.0
@@ -89,6 +88,31 @@ func TestHoldingPeriodReturnPercentage(t *testing.T) {
 	}
 }
 
+func TestHoldingPeriodReturnAnnualized(t *testing.T) {
+	var initialValue float64 = 1000.0
+	var finalValue float64 = 1200.0
+	var holdingPeriodInYears = 2.0
+	var expected float64 = 0.10
+
+	actual := HoldingPeriodReturnAnnualized(initialValue, finalValue, holdingPeriodInYears)
+
+	if compareFloat64(actual, expected) {
+		t.Errorf("Test failed, expected: '%f', got: '%f'", expected, actual)
+	}
+}
+
+func TestHoldingPeriodReturnAnnualizePercentage(t *testing.T) {
+	var initialValue float64 = 1000.0
+	var finalValue float64 = 1200.0
+	var holdingPeriodInYears = 2.0
+	var expected float64 = 9.54
+
+	actual := HoldingPeriodReturnAnnualizedPercentage(initialValue, finalValue, holdingPeriodInYears)
+
+	if compareFloat64(actual, expected) {
+		t.Errorf("Test failed, expected: '%f', got: '%f'", expected, actual)
+	}
+}
 
 func TestFutureValueAnnuity(t *testing.T) {
 	var payment float64 = 100