From 3bb2849e419e07d0f582537a3dc48f7a265596a8 Mon Sep 17 00:00:00 2001
From: xuri <xuri.me@gmail.com>
Date: Sun, 31 Oct 2021 00:15:17 +0800
Subject: [PATCH] ref #65: new formula functions DEVSQ and GEOMEAN

---
 calc.go      | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 calc_test.go | 12 ++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/calc.go b/calc.go
index f346fa2..97ba373 100644
--- a/calc.go
+++ b/calc.go
@@ -365,6 +365,7 @@ type formulaFuncs struct {
 //    DEC2OCT
 //    DECIMAL
 //    DEGREES
+//    DEVSQ
 //    DISC
 //    DOLLARDE
 //    DOLLARFR
@@ -389,6 +390,7 @@ type formulaFuncs struct {
 //    GAMMA
 //    GAMMALN
 //    GCD
+//    GEOMEAN
 //    HARMEAN
 //    HEX2BIN
 //    HEX2DEC
@@ -4924,6 +4926,36 @@ func (fn *formulaFuncs) COUNTBLANK(argsList *list.List) formulaArg {
 	return newNumberFormulaArg(float64(count))
 }
 
+// DEVSQ function calculates the sum of the squared deviations from the sample
+// mean. The syntax of the function is:
+//
+//    DEVSQ(number1,[number2],...)
+//
+func (fn *formulaFuncs) DEVSQ(argsList *list.List) formulaArg {
+	if argsList.Len() < 1 {
+		return newErrorFormulaArg(formulaErrorVALUE, "DEVSQ requires at least 1 numeric argument")
+	}
+	avg, count, result := fn.AVERAGE(argsList), -1, 0.0
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		for _, number := range arg.Value.(formulaArg).ToList() {
+			num := number.ToNumber()
+			if num.Type != ArgNumber {
+				continue
+			}
+			count++
+			if count == 0 {
+				result = math.Pow(num.Number-avg.Number, 2)
+				continue
+			}
+			result += math.Pow(num.Number-avg.Number, 2)
+		}
+	}
+	if count == -1 {
+		return newErrorFormulaArg(formulaErrorNA, formulaErrorNA)
+	}
+	return newNumberFormulaArg(result)
+}
+
 // FISHER function calculates the Fisher Transformation for a supplied value.
 // The syntax of the function is:
 //
@@ -5030,6 +5062,27 @@ func (fn *formulaFuncs) GAMMALN(argsList *list.List) formulaArg {
 	return newErrorFormulaArg(formulaErrorVALUE, "GAMMALN requires 1 numeric argument")
 }
 
+// GEOMEAN function calculates the geometric mean of a supplied set of values.
+// The syntax of the function is:
+//
+//    GEOMEAN(number1,[number2],...)
+//
+func (fn *formulaFuncs) GEOMEAN(argsList *list.List) formulaArg {
+	if argsList.Len() < 1 {
+		return newErrorFormulaArg(formulaErrorVALUE, "GEOMEAN requires at least 1 numeric argument")
+	}
+	product := fn.PRODUCT(argsList)
+	if product.Type != ArgNumber {
+		return product
+	}
+	count := fn.COUNT(argsList)
+	min := fn.MIN(argsList)
+	if product.Number > 0 && min.Number > 0 {
+		return newNumberFormulaArg(math.Pow(product.Number, (1 / count.Number)))
+	}
+	return newErrorFormulaArg(formulaErrorNUM, formulaErrorNUM)
+}
+
 // HARMEAN function calculates the harmonic mean of a supplied set of values.
 // The syntax of the function is:
 //
diff --git a/calc_test.go b/calc_test.go
index ffaec1a..6d46154 100644
--- a/calc_test.go
+++ b/calc_test.go
@@ -763,6 +763,9 @@ func TestCalcCellValue(t *testing.T) {
 		"=COUNTBLANK(1)":        "0",
 		"=COUNTBLANK(B1:C1)":    "1",
 		"=COUNTBLANK(C1)":       "1",
+		// DEVSQ
+		"=DEVSQ(1,3,5,2,9,7)": "47.5",
+		"=DEVSQ(A1:D2)":       "10",
 		// FISHER
 		"=FISHER(-0.9)":   "-1.47221948958322",
 		"=FISHER(-0.25)":  "-0.255412811882995",
@@ -780,6 +783,8 @@ func TestCalcCellValue(t *testing.T) {
 		// GAMMALN
 		"=GAMMALN(4.5)":    "2.45373657084244",
 		"=GAMMALN(INT(1))": "0",
+		// GEOMEAN
+		"=GEOMEAN(2.5,3,0.5,1,3)": "1.6226711115996",
 		// HARMEAN
 		"=HARMEAN(2.5,3,0.5,1,3)":               "1.22950819672131",
 		"=HARMEAN(\"2.5\",3,0.5,1,INT(3),\"\")": "1.22950819672131",
@@ -1977,6 +1982,9 @@ func TestCalcCellValue(t *testing.T) {
 		// COUNTBLANK
 		"=COUNTBLANK()":    "COUNTBLANK requires 1 argument",
 		"=COUNTBLANK(1,2)": "COUNTBLANK requires 1 argument",
+		// DEVSQ
+		"=DEVSQ()":      "DEVSQ requires at least 1 numeric argument",
+		"=DEVSQ(D1:D2)": "#N/A",
 		// FISHER
 		"=FISHER()":         "FISHER requires 1 numeric argument",
 		"=FISHER(2)":        "#N/A",
@@ -1995,6 +2003,10 @@ func TestCalcCellValue(t *testing.T) {
 		"=GAMMALN(F1)":     "GAMMALN requires 1 numeric argument",
 		"=GAMMALN(0)":      "#N/A",
 		"=GAMMALN(INT(0))": "#N/A",
+		// GEOMEAN
+		"=GEOMEAN()":      "GEOMEAN requires at least 1 numeric argument",
+		"=GEOMEAN(0)":     "#NUM!",
+		"=GEOMEAN(D1:D2)": "strconv.ParseFloat: parsing \"Month\": invalid syntax",
 		// HARMEAN
 		"=HARMEAN()":   "HARMEAN requires at least 1 argument",
 		"=HARMEAN(-1)": "#N/A",
-- 
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