public function testLogGamma()
{
$this->assertEquals(857.9336698, Math::logGamma(200), '', 3.0E-7);
$this->assertEquals(log(120), Math::logGamma(6), '', 3.0E-9);
$this->assertEquals(3.9578139676187, Math::logGamma(5.5), '', 3.0E-9);
}
/**
* Evaluate a FunctionNode
*
* Computes the value of a FunctionNode `f(x)`, where f is
* an elementary function recognized by StdMathLexer and StdMathParser.
*
* @see \MathParser\Lexer\StdMathLexer StdMathLexer
* @see \MathParser\StdMathParser StdMathParser
* @throws UnknownFunctionException if the function respresented by the
* FunctionNode is *not* recognized.
*
* @param FunctionNode $node AST to be evaluated
* @retval float
*/
public function visitFunctionNode(FunctionNode $node)
{
$inner = $node->getOperand()->accept($this);
switch ($node->getName()) {
// Trigonometric functions
case 'sin':
return sin($inner);
case 'cos':
return cos($inner);
case 'tan':
return tan($inner);
case 'cot':
return 1 / tan($inner);
// Trigonometric functions, argument in degrees
// Trigonometric functions, argument in degrees
case 'sind':
return sin(deg2rad($inner));
case 'cosd':
return cos(deg2rad($inner));
case 'tand':
return tan(deg2rad($inner));
case 'cotd':
return 1 / tan(deg2rad($inner));
// Inverse trigonometric functions
// Inverse trigonometric functions
case 'arcsin':
return asin($inner);
case 'arccos':
return acos($inner);
case 'arctan':
return atan($inner);
case 'arccot':
return pi() / 2 - atan($inner);
// Exponentials and logarithms
// Exponentials and logarithms
case 'exp':
return exp($inner);
case 'log':
return log($inner);
case 'lg':
return log10($inner);
// Powers
// Powers
case 'sqrt':
return sqrt($inner);
// Hyperbolic functions
// Hyperbolic functions
case 'sinh':
return sinh($inner);
case 'cosh':
return cosh($inner);
case 'tanh':
return tanh($inner);
case 'coth':
return 1 / tanh($inner);
// Inverse hyperbolic functions
// Inverse hyperbolic functions
case 'arsinh':
return asinh($inner);
case 'arcosh':
return acosh($inner);
case 'artanh':
return atanh($inner);
case 'arcoth':
return atanh(1 / $inner);
case 'abs':
return abs($inner);
case 'sgn':
return $inner >= 0 ? 1 : 0;
case '!':
$logGamma = Math::logGamma(1 + $inner);
return exp($logGamma);
case '!!':
if (round($inner) != $inner) {
throw new \UnexpectedValueException("Expecting positive integer (semifactorial)");
}
return Math::SemiFactorial($inner);
default:
throw new UnknownFunctionException($node->getName());
}
}
