From a79a4ddbabaec1f1865ca2ff4fffa15e20e2cf39 Mon Sep 17 00:00:00 2001
From: Mark Baker <mark@lange.demon.co.uk>
Date: Thu, 4 Mar 2021 21:45:56 +0100
Subject: [PATCH] Statistical refactoring - Confidence() and Trend() (#1898)

- Move TREND() functions into the Statistical Trends class
- Unit tests for TREND()
- Create Confidence class for Statistical Confidence functions, and the CONFIDENCE() method
---
 .../Calculation/Calculation.php               |  6 +--
 .../Calculation/Statistical.php               | 46 ++++++-------------
 .../Calculation/Statistical/Confidence.php    | 41 +++++++++++++++++
 .../Calculation/Statistical/Trends.php        | 32 +++++++++++++
 .../Functions/Statistical/GrowthTest.php      |  5 +-
 .../Functions/Statistical/TrendTest.php       | 33 +++++++++++++
 tests/PhpSpreadsheetTests/Shared/FontTest.php | 15 +++---
 tests/PhpSpreadsheetTests/Style/ColorTest.php | 15 +++---
 tests/data/Calculation/Statistical/TREND.php  | 34 ++++++++++++++
 9 files changed, 177 insertions(+), 50 deletions(-)
 create mode 100644 src/PhpSpreadsheet/Calculation/Statistical/Confidence.php
 create mode 100644 tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/TrendTest.php
 create mode 100644 tests/data/Calculation/Statistical/TREND.php

diff --git a/src/PhpSpreadsheet/Calculation/Calculation.php b/src/PhpSpreadsheet/Calculation/Calculation.php
index 04b8ffab..0d06f04e 100644
--- a/src/PhpSpreadsheet/Calculation/Calculation.php
+++ b/src/PhpSpreadsheet/Calculation/Calculation.php
@@ -579,12 +579,12 @@ class Calculation
         ],
         'CONFIDENCE' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'CONFIDENCE'],
+            'functionCall' => [Statistical\Confidence::class, 'CONFIDENCE'],
             'argumentCount' => '3',
         ],
         'CONFIDENCE.NORM' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'CONFIDENCE'],
+            'functionCall' => [Statistical\Confidence::class, 'CONFIDENCE'],
             'argumentCount' => '3',
         ],
         'CONFIDENCE.T' => [
@@ -2454,7 +2454,7 @@ class Calculation
         ],
         'TREND' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'TREND'],
+            'functionCall' => [Statistical\Trends::class, 'TREND'],
             'argumentCount' => '1-4',
         ],
         'TRIM' => [
diff --git a/src/PhpSpreadsheet/Calculation/Statistical.php b/src/PhpSpreadsheet/Calculation/Statistical.php
index 4b5c8094..8a9e3fea 100644
--- a/src/PhpSpreadsheet/Calculation/Statistical.php
+++ b/src/PhpSpreadsheet/Calculation/Statistical.php
@@ -4,6 +4,7 @@ namespace PhpOffice\PhpSpreadsheet\Calculation;
 
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Averages;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Conditional;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Confidence;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Maximum;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Minimum;
@@ -832,6 +833,11 @@ class Statistical
      *
      * Returns the confidence interval for a population mean
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Statistical\Confidence::CONFIDENCE()
+     *      Use the CONFIDENCE() method in the Statistical\Confidence class instead
+     *
      * @param float $alpha
      * @param float $stdDev Standard Deviation
      * @param float $size
@@ -840,23 +846,7 @@ class Statistical
      */
     public static function CONFIDENCE($alpha, $stdDev, $size)
     {
-        $alpha = Functions::flattenSingleValue($alpha);
-        $stdDev = Functions::flattenSingleValue($stdDev);
-        $size = Functions::flattenSingleValue($size);
-
-        if ((is_numeric($alpha)) && (is_numeric($stdDev)) && (is_numeric($size))) {
-            $size = floor($size);
-            if (($alpha <= 0) || ($alpha >= 1)) {
-                return Functions::NAN();
-            }
-            if (($stdDev <= 0) || ($size < 1)) {
-                return Functions::NAN();
-            }
-
-            return self::NORMSINV(1 - $alpha / 2) * $stdDev / sqrt($size);
-        }
-
-        return Functions::VALUE();
+        return Confidence::CONFIDENCE($alpha, $stdDev, $size);
     }
 
     /**
@@ -2941,6 +2931,11 @@ class Statistical
      *
      * Returns values along a linear Trend
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Statistical\Trends::TREND()
+     *      Use the TREND() method in the Statistical\Trends class instead
+     *
      * @param mixed[] $yValues Data Series Y
      * @param mixed[] $xValues Data Series X
      * @param mixed[] $newValues Values of X for which we want to find Y
@@ -2950,22 +2945,7 @@ class Statistical
      */
     public static function TREND($yValues, $xValues = [], $newValues = [], $const = true)
     {
-        $yValues = Functions::flattenArray($yValues);
-        $xValues = Functions::flattenArray($xValues);
-        $newValues = Functions::flattenArray($newValues);
-        $const = ($const === null) ? true : (bool) Functions::flattenSingleValue($const);
-
-        $bestFitLinear = Trend::calculate(Trend::TREND_LINEAR, $yValues, $xValues, $const);
-        if (empty($newValues)) {
-            $newValues = $bestFitLinear->getXValues();
-        }
-
-        $returnArray = [];
-        foreach ($newValues as $xValue) {
-            $returnArray[0][] = $bestFitLinear->getValueOfYForX($xValue);
-        }
-
-        return $returnArray;
+        return Trends::TREND($yValues, $xValues, $newValues, $const);
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Confidence.php b/src/PhpSpreadsheet/Calculation/Statistical/Confidence.php
new file mode 100644
index 00000000..c4c2a7dd
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Confidence.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+class Confidence
+{
+    /**
+     * CONFIDENCE.
+     *
+     * Returns the confidence interval for a population mean
+     *
+     * @param float $alpha
+     * @param float $stdDev Standard Deviation
+     * @param float $size
+     *
+     * @return float|string
+     */
+    public static function CONFIDENCE($alpha, $stdDev, $size)
+    {
+        $alpha = Functions::flattenSingleValue($alpha);
+        $stdDev = Functions::flattenSingleValue($stdDev);
+        $size = Functions::flattenSingleValue($size);
+
+        if ((is_numeric($alpha)) && (is_numeric($stdDev)) && (is_numeric($size))) {
+            $size = floor($size);
+            if (($alpha <= 0) || ($alpha >= 1)) {
+                return Functions::NAN();
+            }
+            if (($stdDev <= 0) || ($size < 1)) {
+                return Functions::NAN();
+            }
+
+            return Statistical::NORMSINV(1 - $alpha / 2) * $stdDev / sqrt($size);
+        }
+
+        return Functions::VALUE();
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Trends.php b/src/PhpSpreadsheet/Calculation/Statistical/Trends.php
index 23bffced..d06214de 100644
--- a/src/PhpSpreadsheet/Calculation/Statistical/Trends.php
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Trends.php
@@ -388,4 +388,36 @@ class Trends
 
         return $bestFitLinear->getStdevOfResiduals();
     }
+
+    /**
+     * TREND.
+     *
+     * Returns values along a linear Trend
+     *
+     * @param mixed[] $yValues Data Series Y
+     * @param mixed[] $xValues Data Series X
+     * @param mixed[] $newValues Values of X for which we want to find Y
+     * @param bool $const a logical value specifying whether to force the intersect to equal 0
+     *
+     * @return array of float
+     */
+    public static function TREND($yValues, $xValues = [], $newValues = [], $const = true)
+    {
+        $yValues = Functions::flattenArray($yValues);
+        $xValues = Functions::flattenArray($xValues);
+        $newValues = Functions::flattenArray($newValues);
+        $const = ($const === null) ? true : (bool) Functions::flattenSingleValue($const);
+
+        $bestFitLinear = Trend::calculate(Trend::TREND_LINEAR, $yValues, $xValues, $const);
+        if (empty($newValues)) {
+            $newValues = $bestFitLinear->getXValues();
+        }
+
+        $returnArray = [];
+        foreach ($newValues as $xValue) {
+            $returnArray[0][] = [$bestFitLinear->getValueOfYForX($xValue)];
+        }
+
+        return $returnArray;
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/GrowthTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/GrowthTest.php
index ce4eef8a..6e1cf7bf 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/GrowthTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/GrowthTest.php
@@ -17,10 +17,11 @@ class GrowthTest extends TestCase
      * @dataProvider providerGROWTH
      *
      * @param mixed $expectedResult
+     * @param mixed $yValues
      */
-    public function testGROWTH($expectedResult, ...$args): void
+    public function testGROWTH($expectedResult, $yValues, ...$args): void
     {
-        $result = Statistical::GROWTH(...$args);
+        $result = Statistical::GROWTH($yValues, ...$args);
 
         self::assertEqualsWithDelta($expectedResult, $result[0], 1E-12);
     }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/TrendTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/TrendTest.php
new file mode 100644
index 00000000..b4f756b5
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/TrendTest.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class TrendTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerGROWTH
+     *
+     * @param mixed $expectedResult
+     * @param mixed $yValues
+     */
+    public function testTREND($expectedResult, $yValues, ...$args): void
+    {
+        $result = Statistical::TREND($yValues, ...$args);
+
+        self::assertEqualsWithDelta($expectedResult, $result[0], 1E-12);
+    }
+
+    public function providerGROWTH()
+    {
+        return require 'tests/data/Calculation/Statistical/TREND.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Shared/FontTest.php b/tests/PhpSpreadsheetTests/Shared/FontTest.php
index 94ab74b6..bc917654 100644
--- a/tests/PhpSpreadsheetTests/Shared/FontTest.php
+++ b/tests/PhpSpreadsheetTests/Shared/FontTest.php
@@ -41,10 +41,11 @@ class FontTest extends TestCase
      * @dataProvider providerFontSizeToPixels
      *
      * @param mixed $expectedResult
+     * @param mixed $size
      */
-    public function testFontSizeToPixels($expectedResult, ...$args): void
+    public function testFontSizeToPixels($expectedResult, $size): void
     {
-        $result = Font::fontSizeToPixels(...$args);
+        $result = Font::fontSizeToPixels($size);
         self::assertEquals($expectedResult, $result);
     }
 
@@ -57,10 +58,11 @@ class FontTest extends TestCase
      * @dataProvider providerInchSizeToPixels
      *
      * @param mixed $expectedResult
+     * @param mixed $size
      */
-    public function testInchSizeToPixels($expectedResult, ...$args): void
+    public function testInchSizeToPixels($expectedResult, $size): void
     {
-        $result = Font::inchSizeToPixels(...$args);
+        $result = Font::inchSizeToPixels($size);
         self::assertEquals($expectedResult, $result);
     }
 
@@ -73,10 +75,11 @@ class FontTest extends TestCase
      * @dataProvider providerCentimeterSizeToPixels
      *
      * @param mixed $expectedResult
+     * @param mixed $size
      */
-    public function testCentimeterSizeToPixels($expectedResult, ...$args): void
+    public function testCentimeterSizeToPixels($expectedResult, $size): void
     {
-        $result = Font::centimeterSizeToPixels(...$args);
+        $result = Font::centimeterSizeToPixels($size);
         self::assertEquals($expectedResult, $result);
     }
 
diff --git a/tests/PhpSpreadsheetTests/Style/ColorTest.php b/tests/PhpSpreadsheetTests/Style/ColorTest.php
index 04028f87..2c017ff4 100644
--- a/tests/PhpSpreadsheetTests/Style/ColorTest.php
+++ b/tests/PhpSpreadsheetTests/Style/ColorTest.php
@@ -11,10 +11,11 @@ class ColorTest extends TestCase
      * @dataProvider providerColorGetRed
      *
      * @param mixed $expectedResult
+     * @param mixed $color
      */
-    public function testGetRed($expectedResult, ...$args): void
+    public function testGetRed($expectedResult, $color, ...$args): void
     {
-        $result = Color::getRed(...$args);
+        $result = Color::getRed($color, ...$args);
         self::assertEquals($expectedResult, $result);
     }
 
@@ -27,10 +28,11 @@ class ColorTest extends TestCase
      * @dataProvider providerColorGetGreen
      *
      * @param mixed $expectedResult
+     * @param mixed $color
      */
-    public function testGetGreen($expectedResult, ...$args): void
+    public function testGetGreen($expectedResult, $color, ...$args): void
     {
-        $result = Color::getGreen(...$args);
+        $result = Color::getGreen($color, ...$args);
         self::assertEquals($expectedResult, $result);
     }
 
@@ -43,10 +45,11 @@ class ColorTest extends TestCase
      * @dataProvider providerColorGetBlue
      *
      * @param mixed $expectedResult
+     * @param mixed $color
      */
-    public function testGetBlue($expectedResult, ...$args): void
+    public function testGetBlue($expectedResult, $color, ...$args): void
     {
-        $result = Color::getBlue(...$args);
+        $result = Color::getBlue($color, ...$args);
         self::assertEquals($expectedResult, $result);
     }
 
diff --git a/tests/data/Calculation/Statistical/TREND.php b/tests/data/Calculation/Statistical/TREND.php
new file mode 100644
index 00000000..418367b2
--- /dev/null
+++ b/tests/data/Calculation/Statistical/TREND.php
@@ -0,0 +1,34 @@
+<?php
+
+return [
+    [
+        [
+            [133953.33333333334],
+            [134971.51515151517],
+            [135989.69696969696],
+            [137007.87878787878],
+            [138026.0606060606],
+            [139044.24242424243],
+            [140062.42424242425],
+            [141080.60606060608],
+            [142098.78787878787],
+            [143116.9696969697],
+            [144135.15151515152],
+            [145153.33333333334],
+        ],
+        [133890, 135000, 135790, 137300, 138130, 139100, 139900, 141120, 141890, 143230, 144000, 145290],
+        [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
+    ],
+    [
+        [
+            [146171.51515151517],
+            [147189.69696969696],
+            [148207.87878787878],
+            [149226.0606060606],
+            [150244.24242424243],
+        ],
+        [133890, 135000, 135790, 137300, 138130, 139100, 139900, 141120, 141890, 143230, 144000, 145290],
+        [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
+        [13, 14, 15, 16, 17],
+    ],
+];