Changeset c97d76a in sasview

Timestamp:

Aug 22, 2016 5:03:51 AM (8 years ago)

Author:

lewis

Branches:

master, ESS_GUI, ESS_GUI_Docs, ESS_GUI_batch_fitting, ESS_GUI_bumps_abstraction, ESS_GUI_iss1116, ESS_GUI_iss879, ESS_GUI_iss959, ESS_GUI_opencl, ESS_GUI_ordering, ESS_GUI_sync_sascalc, costrafo411, magnetic_scatt, release-4.1.1, release-4.1.2, release-4.2.2, ticket-1009, ticket-1094-headless, ticket-1242-2d-resolution, ticket-1243, ticket-1249, ticket885, unittest-saveload

Children:

93b145a

Parents:

9a15a87

git-author:

Lewis O'Driscoll <lewis.o'driscoll@…> (08/22/16 04:41:19)

git-committer:

Lewis O'Driscoll <lewis.o'driscoll@…> (08/22/16 05:03:51)

Message:

Add constraint that sigma > 0

Also update the help file to reflect this change

Location:

src/sas

Files:

• sascalc/corfunc/corfunc_calculator.py (modified) (1 diff)
• sasgui/perspectives/corfunc/media/corfunc_help.rst (modified) (2 diffs)

src/sas/sascalc/corfunc/corfunc_calculator.py

@@ -240 +240 @@
         """Fit the Porod region of the curve"""
         fitp = curve_fit(lambda q, k, sig, bg: self._porod(q, k, sig, bg)*q**2,
-                         q, iq*q**2)[0]
+                         q, iq*q**2, bounds=([-np.inf, 0, -np.inf], [np.inf, np.inf, np.inf]))[0]
         k, sigma, bg = fitp
         return k, sigma, bg

src/sas/sasgui/perspectives/corfunc/media/corfunc_help.rst

@@ -51 +51 @@
 
 .. math::
-    I(Q) = B + KQ^{-4}e^{-Q^2\sigma^2}
+    I(Q) = Bg + KQ^{-4}e^{-Q^2\sigma^2}
 
-Where :math:`B` is the Bonart thermal background, :math:`K` is the Porod
-constant, and :math:`\sigma` describes the electron (or neutron scattering
+Where :math:`Bg` is the Bonart thermal background, :math:`K` is the Porod
+constant, and :math:`\sigma > 0` describes the electron (or neutron scattering
 length) density profile at the interface between crystalline and amorphous
 regions (see figure 1).
@@ -133 +133 @@
 Usage
 -----
-Upon sending data for correlation function analysis, it will be plotted,  
-along with a red bar indicating the lower Q range (used for back-extrapolation), 
-and 2 purple bars indicating the upper qrange (used for forward-extrapolation) 
-[figure 3]. These bars may be moved my clicking and dragging, or by entering 
+Upon sending data for correlation function analysis, it will be plotted,
+along with a red bar indicating the lower Q range (used for back-extrapolation),
+and 2 purple bars indicating the upper qrange (used for forward-extrapolation)
+[figure 3]. These bars may be moved my clicking and dragging, or by entering
 the appropriate value in the Q range input boxes.