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Differences Between: [Versions 400 and 401]

   1  <?php
   2  
   3  namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;
   4  
   5  use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
   6  use PhpOffice\PhpSpreadsheet\Calculation\Exception;
   7  use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
   8  
   9  class BesselY
  10  {
  11      use ArrayEnabled;
  12  
  13      /**
  14       * BESSELY.
  15       *
  16       * Returns the Bessel function, which is also called the Weber function or the Neumann function.
  17       *
  18       *    Excel Function:
  19       *        BESSELY(x,ord)
  20       *
  21       * @param mixed $x A float value at which to evaluate the function.
  22       *                   If x is nonnumeric, BESSELY returns the #VALUE! error value.
  23       *                      Or can be an array of values
  24       * @param mixed $ord The integer order of the Bessel function.
  25       *                       If ord is not an integer, it is truncated.
  26       *                       If $ord is nonnumeric, BESSELY returns the #VALUE! error value.
  27       *                       If $ord < 0, BESSELY returns the #NUM! error value.
  28       *                      Or can be an array of values
  29       *
  30       * @return array|float|string Result, or a string containing an error
  31       *         If an array of numbers is passed as an argument, then the returned result will also be an array
  32       *            with the same dimensions
  33       */
  34      public static function BESSELY($x, $ord)
  35      {
  36          if (is_array($x) || is_array($ord)) {
  37              return self::evaluateArrayArguments([self::class, __FUNCTION__], $x, $ord);
  38          }
  39  
  40          try {
  41              $x = EngineeringValidations::validateFloat($x);
  42              $ord = EngineeringValidations::validateInt($ord);
  43          } catch (Exception $e) {
  44              return $e->getMessage();
  45          }
  46  
  47          if (($ord < 0) || ($x <= 0.0)) {
  48              return ExcelError::NAN();
  49          }
  50  
  51          $fBy = self::calculate($x, $ord);
  52  
  53          return (is_nan($fBy)) ? ExcelError::NAN() : $fBy;
  54      }
  55  
  56      private static function calculate(float $x, int $ord): float
  57      {
  58          // special cases
  59          switch ($ord) {
  60              case 0:
  61                  return self::besselY0($x);
  62              case 1:
  63                  return self::besselY1($x);
  64          }
  65  
  66          return self::besselY2($x, $ord);
  67      }
  68  
  69      /**
  70       * Mollify Phpstan.
  71       *
  72       * @codeCoverageIgnore
  73       */
  74      private static function callBesselJ(float $x, int $ord): float
  75      {
  76          $rslt = BesselJ::BESSELJ($x, $ord);
  77          if (!is_float($rslt)) {
  78              throw new Exception('Unexpected array or string');
  79          }
  80  
  81          return $rslt;
  82      }
  83  
  84      private static function besselY0(float $x): float
  85      {
  86          if ($x < 8.0) {
  87              $y = ($x * $x);
  88              $ans1 = -2957821389.0 + $y * (7062834065.0 + $y * (-512359803.6 + $y * (10879881.29 + $y *
  89                              (-86327.92757 + $y * 228.4622733))));
  90              $ans2 = 40076544269.0 + $y * (745249964.8 + $y * (7189466.438 + $y *
  91                          (47447.26470 + $y * (226.1030244 + $y))));
  92  
  93              return $ans1 / $ans2 + 0.636619772 * self::callBesselJ($x, 0) * log($x);
  94          }
  95  
  96          $z = 8.0 / $x;
  97          $y = ($z * $z);
  98          $xx = $x - 0.785398164;
  99          $ans1 = 1 + $y * (-0.1098628627e-2 + $y * (0.2734510407e-4 + $y * (-0.2073370639e-5 + $y * 0.2093887211e-6)));
 100          $ans2 = -0.1562499995e-1 + $y * (0.1430488765e-3 + $y * (-0.6911147651e-5 + $y * (0.7621095161e-6 + $y *
 101                          (-0.934945152e-7))));
 102  
 103          return sqrt(0.636619772 / $x) * (sin($xx) * $ans1 + $z * cos($xx) * $ans2);
 104      }
 105  
 106      private static function besselY1(float $x): float
 107      {
 108          if ($x < 8.0) {
 109              $y = ($x * $x);
 110              $ans1 = $x * (-0.4900604943e13 + $y * (0.1275274390e13 + $y * (-0.5153438139e11 + $y *
 111                              (0.7349264551e9 + $y * (-0.4237922726e7 + $y * 0.8511937935e4)))));
 112              $ans2 = 0.2499580570e14 + $y * (0.4244419664e12 + $y * (0.3733650367e10 + $y * (0.2245904002e8 + $y *
 113                              (0.1020426050e6 + $y * (0.3549632885e3 + $y)))));
 114  
 115              return ($ans1 / $ans2) + 0.636619772 * (self::callBesselJ($x, 1) * log($x) - 1 / $x);
 116          }
 117  
 118          $z = 8.0 / $x;
 119          $y = $z * $z;
 120          $xx = $x - 2.356194491;
 121          $ans1 = 1.0 + $y * (0.183105e-2 + $y * (-0.3516396496e-4 + $y * (0.2457520174e-5 + $y * (-0.240337019e-6))));
 122          $ans2 = 0.04687499995 + $y * (-0.2002690873e-3 + $y * (0.8449199096e-5 + $y *
 123                      (-0.88228987e-6 + $y * 0.105787412e-6)));
 124  
 125          return sqrt(0.636619772 / $x) * (sin($xx) * $ans1 + $z * cos($xx) * $ans2);
 126      }
 127  
 128      private static function besselY2(float $x, int $ord): float
 129      {
 130          $fTox = 2.0 / $x;
 131          $fBym = self::besselY0($x);
 132          $fBy = self::besselY1($x);
 133          for ($n = 1; $n < $ord; ++$n) {
 134              $fByp = $n * $fTox * $fBy - $fBym;
 135              $fBym = $fBy;
 136              $fBy = $fByp;
 137          }
 138  
 139          return $fBy;
 140      }
 141  }