# Delta2D¶

class sherpa.models.basic.Delta2D(name='delta2d')[source]

Two-dimensional delta function.

The model is only defined at a single point (or bin for integrated grids).

xpos

The coordinate of the signal on the x0 axis.

ypos

The coordinate of the signal on the x1 axis.

ampl

The amplitude.

Notes

The functional form of the model for points is:

f(x0, x1) = ampl if x0 == xpos and x1 == ypos
= 0         otherwise


and for an integrated grid it is:

f(x0lo, x1lo, x0hi, x1hi) = ampl if x0lo <= xpos <= x0hi
x1lo <= ypos <= x1hi
= 0    otherwise


This behavior is different to how the amplitude is handled in other models, such as Const2D.

Attributes Summary

Methods Summary

 apply(outer, *otherargs, **otherkwargs) calc(*args, **kwargs) Evaluate the model on a grid. get_center() guess(dep, *args, **kwargs) Set an initial guess for the parameter values. regrid(*arrays) reset() set_center(xpos, ypos, *args, **kwargs) startup() Called before a model may be evaluated multiple times. teardown() Called after a model may be evaluated multiple times.

Attributes Documentation

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Documentation

apply(outer, *otherargs, **otherkwargs)
calc(*args, **kwargs)[source]

Evaluate the model on a grid.

Parameters: p (sequence of numbers) – The parameter values to use. The order matches the pars field. *args – The model grid. The values can be scalar or arrays, and the number depends on the dimensionality of the model and whether it is being evaluated over an integrated grid or at a point (or points).
get_center()[source]
guess(dep, *args, **kwargs)[source]

Set an initial guess for the parameter values.

Attempt to set the parameter values, and ranges, for the model to match the data values. This is intended as a rough guess, so it is expected that the model is only evaluated a small number of times, if at all.

regrid(*arrays)
reset()
set_center(xpos, ypos, *args, **kwargs)[source]
startup()

Called before a model may be evaluated multiple times.

teardown()

Called after a model may be evaluated multiple times.

setup()