xopto.pf.util.pfmapbase module¶

class PfMap2DBase(param1: Optional[numpy.ndarray] = None, param2: Optional[numpy.ndarray] = None, ng: Optional[int] = None, pf: Optional[xopto.pf.pfbase.PfBase] = None, filename: Optional[str] = None, ncostheta: Optional[int] = None, **kwargs)[source]¶

Bases: object

Base class constructor.

Parameters

param1 (np.ndarray vector) – Sampling points of the first parameter of the scattering phase function.
param2 (np.ndarray vector) – Sampling points of the second parameter of the scattering phase function.
pf (xopto.pf.PfBase) – Scattering phase function instance used with this parameter map.
ncostheta (int) – Number of nodes used to compute the Legendre moments. Use a large number (> 1000) for accurate results. If None, adaptive step integration is used, which is accurate but can become slow.
kwargs (dict) – Additional parameters passed to the constructor of the scattering phase function.

DEFAULT_MAP_FILE = None¶: A filename for the default map. Overload this static member in derived classes.

DEFAULT_MAP_PATH = '/home/miran/.xopto/pyxopto/data/pf'¶: A directory for the precalculated default map. Overload this static member in derived classes.

PLOTSCALEFACTORX = 1.0¶

PLOTSCALEFACTORY = 1.0¶: Base class for computing maps of scattering phase function quantifiers as a function ot the scattering phase functions parameters - only for two-parametric scattering phase functions.

XLABEL = '$first parameter$'¶

YLABEL = '$second parameter$'¶

classmethod default_data_file() → str[source]¶

Creates a full filename for the default data file.

Returns: filename – Full filename of the default data file.
Return type: str

delta(param1: Optional[float] = None, param2: Optional[float] = None) → float[source]¶

Returns the values of delta=(1 - g_3)/(1 - g_1) for the scattering phase function using the specified values of the scattering phase function parameters. If one of the scattering phase function parameters is None, the full map is returned.

Parameters

param1 (float, ndarray) – Value(s) of the first parameter of the scattering phase function.
param2 (float, ndarray) – Value(s) of the second parameter of the scattering phase function.

Returns

g_p – The value(s) of delta.

Return type

float, ndarray

classmethod fromfile(filename: Optional[str] = None) → xopto.pf.util.pfmapbase.PfMap2DBase [source]¶

Loads a scattering phase function map from a file.

Parameters: filename (str) – Source file. If None load the map from the default file or create and save a new default map if a default file does not exist. Location of the default map file is defined by the DEFAULT_MAP_PATH and DEFAULT_MAP_FILE static attributes.

g(param1: Optional[float] = None, param2: Optional[float] = None, p: int = 1) → float[source]¶

Returns the value of the p-the Legendre moment for the scattering phase function using the specified values of the scattering phase function parameters. If one of the scattering phase function parameters is None, the full map is returned.

Parameters

param1 (float or np.ndarray) – Value(s) of the first phase function parameter.
param2 (float or np.ndarray) – Value(s) of the second phase function parameter.
p (int) – Requested Legendre moment (p=1 … anisotropy factor g).

Returns

g_p – The value(s) of the requested Legendre moments.

Return type

float or np.ndarray

gamma(param1: Optional[float] = None, param2: Optional[float] = None) → float[source]¶

Returns the value of $\gamma=(1 - g_2)/(1 - g_1)$ for the scattering phase function ussing the specified values of the scattering phase function parameters. If one of the scattering phase function parameters is None, the full map is returned.

Parameters

param1 (float or np.ndarray) – Value(s) of the first parameter of the scattering phase function.
param2 (float or np.ndarray) – Value(s) of the second parameter of the scattering phase function.

Returns

g_p – The value(s) of gamma.

Return type

float or np.ndarray

gammadelta(param1: Optional[float] = None, param2: Optional[float] = None) → float[source]¶

Returns the value of gamma=(1 - g_2)/(1 - g_1) for the scattering phase function using the specified values of the scattering phase function parameters. If one of the scattering phase function parameters is None, the full map is returned.

Parameters

param1 (float, ndarray) – Value(s) of the first parameter of the scattering phase function.
param2 (float, ndarray) – Value(s) of the second parameter of the scattering phase function.

Returns

g_p – The value(s) of gammas.

Return type

float, ndarray

grid1() → numpy.ndarray[source]¶: Returns a 2D array (meshgrid) of points defining the grid of the first scattering phase function parameter.

grid2() → numpy.ndarray[source]¶: Returns a 2D array (meshgrid) of points defining the grid of the second scattering phase function parameter.

invgamma(g: float, gamma: float) → Tuple[float, float][source]¶

Legendre moments, and from there gamma, are calculated on the fly, using the scattering phase function model. Calculating the scattering phase function moments on the fly is more accurate then using a precalculated map.

Parameters

g (float) – Target value of the first Legendre moment.
gamma (float) – Target value of parameter gamma.

Returns

param1, param2 – The estimated values of the scattering phase function parameters.

Return type

float, float

invgammadelta(gamma: float, delta: float, **kwargs) → Tuple[float, float][source]¶

Legendre moments, and from there gamma and delta, are calculated on the fly, using the scattering phase function model. Calculating the scattering phase function moments on the fly is more accurate then using a precalculated map.

Parameters

gamma (float) – Target value of parameter gamma.
delta (float) – Target value of parameter delta.
kwargs (dict) – Keyword arguments passed to the fmin_l_bfgs_b optimization function.

Returns

param1, param2 – The estimated values of the scattering phase function parameters.

Return type

float, float

invsigma(g: float, sigma: float) → Tuple[float, float][source]¶

Legendre moments, and from there sigma, are calculated on the fly, using the scattering phase function model. Calculating the phase function moments on the fly is more accurate then using a precalculated map.

Parameters

g (float) – Target value of the first Legendre moment.
sigma (float) – Target value of parameter sigma.

Returns

param1, param2 – The estimated values of the scattering phase function parameters.

Return type

float, float

n1() → int[source]¶: Returns the number of points defining the grid of the first scattering phase function parameter.

n2() → int[source]¶: Returns the number of points defining the grid of the second scattering phase function parameter.

ng() → int[source]¶: Returns the number of Legendre moments.

param1() → numpy.ndarray[source]¶: Returns a vector of points defining the grid of the first scattering phase function parameter.

param2() → numpy.ndarray[source]¶: Returns a vector of points defining the grid of the second scattering phase function parameter.

pf() → xopto.pf.pfbase.PfBase [source]¶: Type/class of the scattering phase function that is used in this map.

pf_type_name() → str[source]¶: Type name of the scattering phase function that is used in this map.

save(filename: str)[source]¶

Save instance to a file.

Parameters: filename (str) – The target file name.

show()[source]¶: Show the scattering phase function maps using matplotlib.

sigma(param1: Optional[float] = None, param2: Optional[float] = None, ng: int = 15) → float[source]¶

Returns the value of sigma for the scattering phase function at the specified values of the scattering phase function parameters. If one of the scattering phase function parameters is None, the full map is returned.

Parameters

param1 (float, ndarray) – Value(s) of the GK phase function parameter.
param2 (float, ndarray) – Value(s) of the GK phase function parameter.
ng (int) – The number of Legendre moments that is used for sigma calculation.

Returns

g_p – The value(s) of sigma.

Return type

float, ndarray

load_map(filename: str) → xopto.pf.util.pfmapbase.PfMap2DBase [source]¶: Loads any of the scattering phase function maps from a file. For details see the documentation of MieFractalPolystyreneMap, MiePolystyreneMap, MHgMap, GkMap and MPcMap.