Source code for pyspeckit.spectrum.models.modelgrid

Model Grid
Fit a line based on parameters output from a grid of models

Module API
import numpy as np
from pyspeckit.mpfit import mpfit
import matplotlib.cbook as mpcb
import copy
    import scipy.interpolate
    import scipy.ndimage
    scipyOK = True
except ImportError:

[docs]def gaussian_line(xax, maxamp, tau, offset, width): """ A Gaussian line function in which the """ return np.exp(-(xax-offset)**2/(2.0*width**2)) * maxamp * (1.0-np.exp(-1*tau))
[docs]def line_params_2D(gridval1, gridval2, griddim1, griddim2, valuegrid): """ Given a 2D grid of modeled line values - the amplitude, e.g. excitation temperature, and the optical depth, tau - return the model spectrum griddims contains the names of the axes and their values... it should have the same number of entries as gridpars """ if not scipyOK: raise ImportError("Scipy could not be imported, therefore interpolation is not available.") #matchpt1 = np.argmin( np.abs( gridval1 - griddim1[0,:] )) #matchpt2 = np.argmin( np.abs( gridval2 - griddim2[:,0] )) return scipy.ndimage.map_coordinates(valuegrid,np.array([[gridval2],[gridval1]]),order=1) interpgrid = scipy.interpolate.interp2d( griddim1[ gridval1-5:gridval1+5, gridval2-5:gridval2+5].ravel(), griddim2[ gridval1-5:gridval1+5, gridval2-5:gridval2+5].ravel(), valuegrid[gridval1-5:gridval1+5, gridval2-5:gridval2+5].ravel()) return interpgrid(gridval1,gridval2)
[docs]def line_model_2par(xax, center, width, gridval1, gridval2, griddim1, griddim2, maxampgrid, taugrid, linefunction=gaussian_line): """ Returns the spectral line that matches the given x-axis xax, center, width must be in the same units! """ maxamp = line_params_2D(gridval1, gridval2, griddim1, griddim2, maxampgrid) tau = line_params_2D(gridval1, gridval2, griddim1, griddim2, taugrid) return linefunction(xax,maxamp,tau,offset,width)