Module: Mathpack::Functions

Defined in:
lib/mathpack/functions.rb

Class Method Summary collapse

Class Method Details

.beta(a, b) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 11

def self.beta(a, b)
  gamma(a) * gamma(b) / gamma(a + b)
end

.dawson_minus(x) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 19

def self.dawson_minus(x)
  Math.exp(x**2) * Mathpack::Integration.integrate(from: 0.0, to: x) { |x| Math.exp(-x**2) }
end

.dawson_plus(x) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 15

def self.dawson_plus(x)
  Math.exp(-x**2) * Mathpack::Integration.integrate(from: 0.0, to: x) { |x| Math.exp(x**2) }
end

.erf(x) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 7

def self.erf(x)
  1.0 / (2.0 * Math::PI)**0.5 * Mathpack::Integration.integrate(from: -Float::INFINITY, to: x) { |u| Math.exp(-u**2 / 2.0) }
end

.gamma(t) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 3

def self.gamma(t)
  Mathpack::Integration.integrate(from: 0.0, to: Float::INFINITY) { |x| x**(t-1) * Math.exp(-x) }
end

.heaviside(x) ⇒ Object 



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# File 'lib/mathpack/functions.rb', line 23

def self.heaviside(x)
  x <= 0.0 ? 0 : 1
end