Changeset 87964ac in sasmodels

Timestamp:

May 17, 2018 7:10:20 PM (6 years ago)

Author:

Paul Kienzle <pkienzle@…>

Branches:

master, core_shell_microgels, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests

Children:

65fbf7c

Parents:

df0d2ca

Message:

correct pinhole demo for truncated gaussian weight

File:

• sasmodels/resolution.py (modified) (4 diffs)

sasmodels/resolution.py

@@ -106 +106 @@
     *q* points at which the data is measured.
 
-    *dqx* slit width in qx
-
-    *dqy* slit height in qy
+    *qx_width* slit width in qx
+
+    *qy_width* slit height in qy
 
     *q_calc* is the list of points to calculate, or None if this should
@@ -513 +513 @@
 
 
-def gaussian(q, q0, dq):
-    """
-    Return the Gaussian resolution function.
+def gaussian(q, q0, dq, nsigma=2.5):
+    """
+    Return the truncated Gaussian resolution function.
 
     *q0* is the center, *dq* is the width and *q* are the points to evaluate.
     """
-    return exp(-0.5*((q-q0)/dq)**2)/(sqrt(2*pi)*dq)
+    # Calculate the density of the tails; the resulting gaussian needs to be
+    # scaled by this amount in ordere to integrate to 1.0
+    two_tail_density = 2 * (1 + erf(-nsigma/sqrt(2)))/2
+    return exp(-0.5*((q-q0)/dq)**2)/(sqrt(2*pi)*dq)/(1-two_tail_density)
 
 
@@ -696 +699 @@
         output = resolution.apply(theory)
         np.testing.assert_equal(output, self.y)
+
+    # TODO: turn pinhole/slit demos into tests
 
     def test_pinhole(self):
@@ -1104 +1109 @@
 
     if isinstance(resolution, Slit1D):
-        width, height = resolution.dqx, resolution.dqy
+        width, height = resolution.qx_width, resolution.qy_width
         Iq_romb = romberg_slit_1d(resolution.q, width, height, model, pars)
     else: