Changeset 65fbf7c in sasmodels for sasmodels/data.py
- Timestamp:
- May 21, 2018 3:33:49 PM (6 years ago)
- Branches:
- master, core_shell_microgels, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests
- Children:
- 2b2d431
- Parents:
- 87964ac
- File:
-
- 1 edited
Legend:
- Unmodified
- Added
- Removed
-
sasmodels/data.py
rd86f0fc r65fbf7c 36 36 37 37 import numpy as np # type: ignore 38 from numpy import sqrt, sin, cos, pi 38 39 39 40 # pylint: disable=unused-import … … 301 302 302 303 303 def empty_data1D(q, resolution=0.0 ):304 def empty_data1D(q, resolution=0.0, L=0., dL=0.): 304 305 # type: (np.ndarray, float) -> Data1D 305 """306 r""" 306 307 Create empty 1D data using the given *q* as the x value. 307 308 308 *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 $q = 4\pi/\lambda \sin(\theta)$. 309 313 """ 310 314 … … 313 317 Iq, dIq = None, None 314 318 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) 316 333 data.filename = "fake data" 317 334 return data
Note: See TracChangeset
for help on using the changeset viewer.