Files
edx-platform/common/lib/calc/calcfunctions.py
2013-06-10 11:35:34 -04:00

100 lines
1.5 KiB
Python

"""
Provide the mathematical functions that numpy doesn't.
Specifically, the secant/cosecant/cotangents and their inverses and
hyperbolic counterparts
"""
import numpy
# Normal Trig
def sec(arg):
"""
Secant
"""
return 1 / numpy.cos(arg)
def csc(arg):
"""
Cosecant
"""
return 1 / numpy.sin(arg)
def cot(arg):
"""
Cotangent
"""
return 1 / numpy.tan(arg)
# Inverse Trig
# http://en.wikipedia.org/wiki/Inverse_trigonometric_functions#Relationships_among_the_inverse_trigonometric_functions
def arcsec(val):
"""
Inverse secant
"""
return numpy.arccos(1. / val)
def arccsc(val):
"""
Inverse cosecant
"""
return numpy.arcsin(1. / val)
def arccot(val):
"""
Inverse cotangent
"""
if numpy.real(val) < 0:
return -numpy.pi / 2 - numpy.arctan(val)
else:
return numpy.pi / 2 - numpy.arctan(val)
# Hyperbolic Trig
def sech(arg):
"""
Hyperbolic secant
"""
return 1 / numpy.cosh(arg)
def csch(arg):
"""
Hyperbolic cosecant
"""
return 1 / numpy.sinh(arg)
def coth(arg):
"""
Hyperbolic cotangent
"""
return 1 / numpy.tanh(arg)
# And their inverses
def arcsech(val):
"""
Inverse hyperbolic secant
"""
return numpy.arccosh(1. / val)
def arccsch(val):
"""
Inverse hyperbolic cosecant
"""
return numpy.arcsinh(1. / val)
def arccoth(val):
"""
Inverse hyperbolic cotangent
"""
return numpy.arctanh(1. / val)