Changeset 65fbf7c in sasmodels


Ignore:
Timestamp:
May 21, 2018 5:33:49 PM (7 months ago)
Author:
Paul Kienzle <pkienzle@…>
Branches:
master, F1F2models_grethe, beta_approx, cuda-test, py3, ticket-1015-gpu-mem-error, ticket-1015-quick-fix, ticket-1157, ticket-608-user-defined-weights, ticket_1156
Children:
2b2d431
Parents:
87964ac
Message:

play with resolution defined by fixed dtheta,dlambda

Location:
sasmodels
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • sasmodels/compare.py

    r1198f90 r65fbf7c  
    667667        if opts['zero']: 
    668668            q = np.hstack((0, q)) 
    669         data = empty_data1D(q, resolution=res) 
     669        # TODO: provide command line control of lambda and Delta lambda/lambda 
     670        #L, dLoL = 5, 0.14/np.sqrt(6)  # wavelength and 14% triangular FWHM 
     671        L, dLoL = 0, 0 
     672        data = empty_data1D(q, resolution=res, L=L, dL=L*dLoL) 
    670673        index = slice(None, None) 
    671674    return data, index 
     
    871874    # Plot if requested 
    872875    view = opts['view'] 
     876    #view = 'log' 
    873877    if limits is None: 
    874878        vmin, vmax = np.inf, -np.inf 
  • sasmodels/data.py

    rd86f0fc r65fbf7c  
    3636 
    3737import numpy as np  # type: ignore 
     38from numpy import sqrt, sin, cos, pi 
    3839 
    3940# pylint: disable=unused-import 
     
    301302 
    302303 
    303 def empty_data1D(q, resolution=0.0): 
     304def empty_data1D(q, resolution=0.0, L=0., dL=0.): 
    304305    # type: (np.ndarray, float) -> Data1D 
    305     """ 
     306    r""" 
    306307    Create empty 1D data using the given *q* as the x value. 
    307308 
    308     *resolution* dq/q defaults to 5%. 
     309    rms *resolution* $\Delta q/q$ defaults to 0%.  If wavelength *L* and rms 
     310    wavelength divergence *dL* are defined, then *resolution* defines 
     311    rms $\Delta \theta/\theta$ for the lowest *q*, with $\theta$ derived from 
     312    $q = 4\pi/\lambda \sin(\theta)$. 
    309313    """ 
    310314 
     
    313317    Iq, dIq = None, None 
    314318    q = np.asarray(q) 
    315     data = Data1D(q, Iq, dx=resolution * q, dy=dIq) 
     319    if L != 0 and resolution != 0: 
     320        theta = np.arcsin(q*L/(4*pi)) 
     321        dtheta = theta[0]*resolution 
     322        ## Solving Gaussian error propagation from 
     323        ##   Dq^2 = (dq/dL)^2 DL^2 + (dq/dtheta)^2 Dtheta^2 
     324        ## gives 
     325        ##   (Dq/q)^2 = (DL/L)**2 + (Dtheta/tan(theta))**2 
     326        ## Take the square root and multiply by q, giving 
     327        ##   Dq = (4*pi/L) * sqrt((sin(theta)*dL/L)**2 + (cos(theta)*dtheta)**2) 
     328        dq = (4*pi/L) * sqrt((sin(theta)*dL/L)**2 + (cos(theta)*dtheta)**2) 
     329    else: 
     330        dq = resolution * q 
     331 
     332    data = Data1D(q, Iq, dx=dq, dy=dIq) 
    316333    data.filename = "fake data" 
    317334    return data 
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