Classes

class pymsg.SpecGrid(file_name)

The SpecGrid class represents a grid of spectroscopic intensity data.

This grid may be used to interpolate the intensity (or related quantities) across a wavelength abscissa and for a set of photospheric parameter values.

__init__(file_name)

SpecGrid constructor (via loading data from a specgrid file).

Parameters:

file_name (string) – Name of the file

Returns:

Constructed object.

Return type:

pymsg.SpecGrid

Raises:

• FileNotFound – If the the file cannot be found.

• TypeError – If the file contains an incorrect datatype.

property rank

Number of dimensions in grid.

Type:

int

property axis_labels

Photospheric parameter axis labels.

Type:

list

property axis_x_min

Photospheric parameter axis minima.

Type:

dict

property axis_x_max

Photospheric parameter axis maxima.

Type:

dict

property lam_min

Minimum wavelength of grid (Å).

Type:

double

property lam_max

Maximum wavelength of grid (Å).

Type:

double

property cache_lam_min

Minimum wavelength of grid cache (Å).

Type:

double

property cache_lam_max

Maximum wavelength of grid cache (Å).

Type:

double

property cache_usage

Current memory usage of grid cache (MB).

Type:

int

property cache_limit

Maximum memory usage of grid cache (MB).

Type:

int

flush_cache()

Flush the grid cache

intensity(x, mu, lam, deriv=None)

Evaluate the spectroscopic intensity.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.b

• mu (double) – Cosine of angle of emergence relative to surface normal.

• lam (numpy.ndarray) – Wavelength abscissa (Å).

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

Spectroscopic intensity (erg/cm^2/s/Å/sr) in bins delineated by lam; length len(lam)-1.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x, mu, or any part of the wavelength abscissa falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

E_moment(x, k, lam, deriv=None)

Evaluate the spectroscopic intensity E-moment.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• k (int) – Degree of moment.

• lam (numpy.ndarray) – Wavelength abscissa (Å).

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

Spectroscopic intensity E-moment (erg/cm^2/s/Å) in bins delineated by lam; length len(lam)-1.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x, k, or any part of the wavelength abscissa falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

D_moment(x, l, lam, deriv=None)

Evaluate the spectroscopic intensity D-moment.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• l (int) – Harmonic degree of moment.

• lam (numpy.ndarray) – Wavelength abscissa (Å).

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

Spectroscopic intensity D-moment (erg/cm^2/s/Å) in bins delineated by lam; length len(lam)-1.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x, l, or any part of the wavelength abscissa falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

flux(x, lam, deriv=None)

Evaluate the spectroscopic flux.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• lam (numpy.ndarray) – Wavelength abscissa (Å)

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

Spectroscopic flux (erg/cm^2/s/Å) in bins delineated by lam; length len(lam)-1.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x or any part of the wavelength abscissa falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

adjust_x(x, dx)

Adjust photospheric parameters in a specified direction, until they fall within the valid part of the grid.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• dx (dict) – Photospheric parameter adjustment direction; keys must match axis_labels property, values must be double. The overall scaling is unimportant, but at least one value must be non-zero.

Returns:

Adjusted photospheric parameters.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If no valid x can be found, or if dx is invalid.

class pymsg.PhotGrid(file_name, passband_file_name=None)

The PhotGrid class represents a grid of photometric intensity data.

This grid may be used to interpolate the intensity (or related quantities) for a set of photospheric parameter values.

__init__(file_name, passband_file_name=None)

PhotGrid constructor (via loading data from a photgrid file, or

from a specgrid file together with a passband file).

Parameters:

• file_name (string) – Name of grid file.

• passband_file_name (string) – Name of passband file (if file_name corresponds to a specgrid file)

Returns:

Constructed object.

Return type:

pymsg.PhotGrid

Raises:

• FileNotFound – If either file cannot be found.

• TypeError – If either file contains an incorrect datatype.

property rank

Number of dimensions in grid.

Type:

int

property axis_labels

Photospheric parameter axis labels.

Type:

list

property axis_x_min

Photospheric parameter axis minima.

Type:

dict

property axis_x_max

Photospheric parameter axis maxima.

Type:

dict

property cache_usage

Current memory usage of grid cache (MB).

Type:

int

property cache_limit

Maximum memory usage of grid cache (MB).

Type:

int

flush_cache()

Flush the grid cache

intensity(x, mu, deriv=None)

Evaluate the photometric intensity, normalized to the zero- point flux.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• mu (double) – Cosine of angle of emergence relative to surface normal.

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

photometric intensity (/sr).

Return type:

double

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x or mu falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

E_moment(x, k, deriv=None)

Evaluate the photometric intensity E-moment, normalized to the zero-point flux.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• k (int) – Degree of moment.

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

photometric intensity E-moment.

Return type:

double

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x or k falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

D_moment(x, l, deriv=None)

Evaluate the photometric intensity D-moment, normalized to the zero-point flux.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• l (int) – Harmonic degree of moment.

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

photometric intensity D-moment.

Return type:

double

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x or l falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

flux(x, deriv=None)

Evaluate the photometric flux, normalized to the zero-point flux.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• deriv (dict, optional) – Flags indicating whether to evaluate derivative with respect to each photospheric parameter; keys must match the axis_labels property, values must be boolean.

Returns:

photometric flux.

Return type:

double

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If x or l falls outside the bounds of the grid.

• LookupError – If x falls in a grid void.

adjust_x(x, dx)

Adjust photospheric parameters in a specified direction, until they fall within the valid part of the grid.

Parameters:

• x (dict) – Photospheric parameters; keys must match axis_labels property, values must be double.

• dx (dict) – Photospheric parameter adjustment direction; keys must match axis_labels property, values must be double. The overall scaling is unimportant, but at least one value must be non-zero.

Returns:

Adjusted photospheric parameters.

Return type:

numpy.ndarray

Raises:

• KeyError – If x does not define all keys appearing in the axis_labels property.

• ValueError – If no valid x can be found, or if dx is invalid.