Package lib :: Package order :: Module order_parameters
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Module order_parameters

source code

Module for the conversion of order parameters to specific model parameters and vice versa.

Functions [hide private]
float
iso_cone_theta_to_S(theta)
Convert the isotropic cone angle to the order parameter S.
source code
float
iso_cone_S_to_theta(S)
Convert the isotropic cone order parameter S into the cone angle.
source code
Variables [hide private]
  __package__ = 'lib.order'

Imports: acos, cos, pi, sqrt


Function Details [hide private]

iso_cone_theta_to_S(theta)

source code 

Convert the isotropic cone angle to the order parameter S.

This uses Woessner's diffusion in a cone order parameter defined as:

   S = 1/2 (1 + cos(theta)) * cos(theta)
Parameters:
  • theta (float) - The isotropic cone angle.
Returns: float
The order parameter value.

iso_cone_S_to_theta(S)

source code 

Convert the isotropic cone order parameter S into the cone angle.

This uses Woessner's diffusion in a cone order parameter defined as:

   S = 1/2 (1 + cos(theta)) * cos(theta)

The conversion equation is:

   theta = acos((sqrt(8.0*S + 1) - 1)/2)

Hence the cone angle is only between 0 and 2pi/3, as the order parameter for higher cone angles is ambiguous.

Parameters:
  • S (float) - The order parameter value (not squared).
Returns: float
The value of cos(theta).