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lib/PhpSpreadsheet/Calculation/MathTrig/Factorial.php

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+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
+
+use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
+use PhpOffice\PhpSpreadsheet\Calculation\Exception;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+class Factorial
+{
+    use ArrayEnabled;
+
+    /**
+     * FACT.
+     *
+     * Returns the factorial of a number.
+     * The factorial of a number is equal to 1*2*3*...* number.
+     *
+     * Excel Function:
+     *        FACT(factVal)
+     *
+     * @param array|float $factVal Factorial Value, or can be an array of numbers
+     *
+     * @return array|float|int|string Factorial, or a string containing an error
+     *         If an array of numbers is passed as the argument, then the returned result will also be an array
+     *            with the same dimensions
+     */
+    public static function fact($factVal): array|string|float|int
+    {
+        if (is_array($factVal)) {
+            return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $factVal);
+        }
+
+        try {
+            $factVal = Helpers::validateNumericNullBool($factVal);
+            Helpers::validateNotNegative($factVal);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $factLoop = floor($factVal);
+        if ($factVal > $factLoop) {
+            if (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_GNUMERIC) {
+                return Statistical\Distributions\Gamma::gammaValue($factVal + 1);
+            }
+        }
+
+        $factorial = 1;
+        while ($factLoop > 1) {
+            $factorial *= $factLoop--;
+        }
+
+        return $factorial;
+    }
+
+    /**
+     * FACTDOUBLE.
+     *
+     * Returns the double factorial of a number.
+     *
+     * Excel Function:
+     *        FACTDOUBLE(factVal)
+     *
+     * @param array|float $factVal Factorial Value, or can be an array of numbers
+     *
+     * @return array|float|int|string Double Factorial, or a string containing an error
+     *         If an array of numbers is passed as the argument, then the returned result will also be an array
+     *            with the same dimensions
+     */
+    public static function factDouble($factVal): array|string|float|int
+    {
+        if (is_array($factVal)) {
+            return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $factVal);
+        }
+
+        try {
+            $factVal = Helpers::validateNumericNullSubstitution($factVal, 0);
+            Helpers::validateNotNegative($factVal);
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $factLoop = floor($factVal);
+        $factorial = 1;
+        while ($factLoop > 1) {
+            $factorial *= $factLoop;
+            $factLoop -= 2;
+        }
+
+        return $factorial;
+    }
+
+    /**
+     * MULTINOMIAL.
+     *
+     * Returns the ratio of the factorial of a sum of values to the product of factorials.
+     *
+     * @param mixed[] $args An array of mixed values for the Data Series
+     *
+     * @return float|int|string The result, or a string containing an error
+     */
+    public static function multinomial(...$args): string|int|float
+    {
+        $summer = 0;
+        $divisor = 1;
+
+        try {
+            // Loop through arguments
+            foreach (Functions::flattenArray($args) as $argx) {
+                $arg = Helpers::validateNumericNullSubstitution($argx, null);
+                Helpers::validateNotNegative($arg);
+                $arg = (int) $arg;
+                $summer += $arg;
+                $divisor *= self::fact($arg);
+            }
+        } catch (Exception $e) {
+            return $e->getMessage();
+        }
+
+        $summer = self::fact($summer);
+
+        return is_numeric($summer) ? ($summer / $divisor) : ExcelError::VALUE();
+    }
+}