Changeset 3d40839 in sasmodels for doc/guide/orientation

Timestamp:

Oct 28, 2017 9:28:22 PM (7 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:

0db85af

Parents:

e964ab1

Message:

update orientation docs

File:

• doc/guide/orientation/orientation.rst (modified) (4 diffs)

doc/guide/orientation/orientation.rst

@@ -8 +8 @@
 or orientation in a magnetic field.
 
-In general we first need to define the mean, or a reference orientation
+In general we first need to define the reference orientation
 of the particles with respect to the incoming neutron or X-ray beam. This
 is done using three angles: $\theta$ and $\phi$ define the orientation of
@@ -29 +29 @@
 
     Definition of angles for oriented elliptical cylinder, where axis_ratio
-    b/a is shown >1, Note that rotation $\theta$, initially in the $xz$
-    plane, is carried out first, then rotation $\phi$ about the $z$ axis,
+    b/a is shown >1, Note that rotation $\theta$, initially in the $x$-$z$
+    plane, is carried out first, then rotation $\phi$ about the $z$-axis,
     finally rotation $\Psi$ is around the axis of the cylinder. The neutron
     or X-ray beam is along the $z$ axis.
@@ -42 +42 @@
 Having established the mean direction of the particle we can then apply
 angular orientation distributions. This is done by a numerical integration
-over a range of angles in a similar way to polydispersity for particle size.
+over a range of angles in a similar way to particle size dispersity.
 In the current version of sasview the orientational dispersity is defined
 with respect to the axes of the particle.
 
-The $\theta$ and $\phi$ parameters to orient the cylinder only appear in the
-model when fitting 2d data. On introducing "Orientational Distribution" in
+The $\theta$ and $\phi$ orientation parameters for the cylinder only appear
+when fitting 2d data. On introducing "Orientational Distribution" in
 the angles, "distribution of theta" and "distribution of phi" parameters will
 appear. These are actually rotations about the axes $\delta_1$ and $\delta_2$
 of the cylinder, the $b$ and $a$ axes of the cylinder cross section. (When
 $\theta = \phi = 0$ these are parallel to the $Y$ and $X$ axes of the
-instrument.) The third orientation distribution, in $\psi$, is about the $c$
+instrument.) The third orientation distribution, in $\Psi$, is about the $c$
 axis of the particle. Some experimentation may be required to understand the
 2d patterns fully. A number of different shapes of distribution are
@@ -65 +65 @@
 numerical integrations over one or more variables, so care should be taken,
 especially with very large particles or more extreme aspect ratios. Users can
-experiment with the values of Npts and Nsigs, the number of steps used in the
+experiment with the values of *Npts* and *Nsigs*, the number of steps used in the
 integration and the range spanned in number of standard deviations. The
 standard deviation is entered in units of degrees. For a rectangular
-(uniform) distribution the full width should be $\pm\sqrt(3)$ ~ 1.73 standard
+(uniform) distribution the full width should be $\pm \sqrt(3)$ ~ 1.73 standard
 deviations (this may be changed soon).