# tablepress/3.4/libraries/vendor/PhpSpreadsheet/Calculation/Engineering/Erf.php

TablePress – Tables in WordPress made easy, version 3.4. 114 lines.

- Page: https://pluginprobe.com/plugins/tablepress/3.4/code/libraries/vendor/PhpSpreadsheet/Calculation/Engineering/Erf.php
- Raw: https://pluginprobe.com/plugins/tablepress/3.4/raw/libraries/vendor/PhpSpreadsheet/Calculation/Engineering/Erf.php
- Modified: 2025-08-26T04:06:14+00:00

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```php
<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Calculation\Engineering;

use TablePress\PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Functions;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;

class Erf
{
	use ArrayEnabled;

	private const TWO_SQRT_PI = 1.128379167095512574;

	/**
	 * ERF.
	 *
	 * Returns the error function integrated between the lower and upper bound arguments.
	 *
	 *    Note: In Excel 2007 or earlier, if you input a negative value for the upper or lower bound arguments,
	 *            the function would return a #NUM! error. However, in Excel 2010, the function algorithm was
	 *            improved, so that it can now calculate the function for both positive and negative ranges.
	 *            PhpSpreadsheet follows Excel 2010 behaviour, and accepts negative arguments.
	 *
	 *    Excel Function:
	 *        ERF(lower[,upper])
	 *
	 * @param mixed $lower Lower bound float for integrating ERF
	 *                      Or can be an array of values
	 * @param mixed $upper Upper bound float for integrating ERF.
	 *                           If omitted, ERF integrates between zero and lower_limit
	 *                      Or can be an array of values
	 *
	 * @return array<mixed>|float|string If an array of numbers is passed as an argument, then the returned result will also be an array
	 *            with the same dimensions
	 */
	public static function ERF($lower, $upper = null)
	{
		if (is_array($lower) || is_array($upper)) {
			return self::evaluateArrayArguments([self::class, __FUNCTION__], $lower, $upper);
		}

		if (is_numeric($lower)) {
			if ($upper === null) {
				return self::erfValue($lower);
			}
			if (is_numeric($upper)) {
				return self::erfValue($upper) - self::erfValue($lower);
			}
		}

		return ExcelError::VALUE();
	}

	/**
	 * ERFPRECISE.
	 *
	 * Returns the error function integrated between the lower and upper bound arguments.
	 *
	 *    Excel Function:
	 *        ERF.PRECISE(limit)
	 *
	 * @param mixed $limit Float bound for integrating ERF, other bound is zero
	 *                      Or can be an array of values
	 *
	 * @return array<mixed>|float|string If an array of numbers is passed as an argument, then the returned result will also be an array
	 *            with the same dimensions
	 */
	public static function ERFPRECISE($limit)
	{
		if (is_array($limit)) {
			return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $limit);
		}

		return self::ERF($limit);
	}

	/**
				 * @param mixed $value
				 */
				private static function makeFloat($value): float
	{
		return is_numeric($value) ? ((float) $value) : 0.0;
	}

	/**
				 * Method to calculate the erf value.
				 * @param float|int|string $value
				 */
				public static function erfValue($value): float
	{
		$value = (float) $value;
		if (abs($value) > 2.2) {
			return 1 - self::makeFloat(ErfC::ERFC($value));
		}
		$sum = $term = $value;
		$xsqr = ($value * $value);
		$j = 1;
		do {
			$term *= $xsqr / $j;
			$sum -= $term / (2 * $j + 1);
			++$j;
			$term *= $xsqr / $j;
			$sum += $term / (2 * $j + 1);
			++$j;
			if ($sum == 0.0) {
				break;
			}
		} while (abs($term / $sum) > Functions::PRECISION);

		return self::TWO_SQRT_PI * $sum;
	}
}

```