Changeset 7e6bc45e in sasmodels for doc/guide/plugin.rst


Ignore:
Timestamp:
Dec 20, 2017 2:33:39 PM (2 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:
06ee63c
Parents:
93fbc34
Message:

update orientation docs

File:
1 edited

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  • doc/guide/plugin.rst

    rc654160 r7e6bc45e  
    538538If the scattering is dependent on the orientation of the shape, then you 
    539539will need to include *orientation* parameters *theta*, *phi* and *psi* 
    540 at the end of the parameter table.  Shape orientation uses *a*, *b* and *c* 
    541 axes, corresponding to the *x*, *y* and *z* axes in the laboratory coordinate 
    542 system, with *z* along the beam and *x*-*y* in the detector plane, with *x* 
    543 horizontal and *y* vertical.  The *psi* parameter rotates the shape 
    544 about its *c* axis, the *theta* parameter then rotates the *c* axis toward 
    545 the *x* axis of the detector, then *phi* rotates the shape in the detector 
    546 plane.  (Prior to these rotations, orientation dispersity will be applied 
    547 as roll-pitch-yaw, rotating *c*, then *b* then *a* in the shape coordinate 
    548 system.)  A particular *qx*, *qy* point on the detector, then corresponds 
    549 to *qa*, *qb*, *qc* with respect to the shape. 
    550  
    551 The oriented C model is called as *Iqabc(qa, qb, qc, par1, par2, ...)* where 
     540at the end of the parameter table.  As described in the section 
     541:ref:`orientation`, the individual $(q_x, q_y)$ points on the detector will 
     542be rotated into $(q_a, q_b, q_c)$ points relative to the sample in its 
     543canonical orientation with $a$-$b$-$c$ aligned with $x$-$y$-$z$ in the 
     544laboratory frame and beam travelling along $-z$. 
     545 
     546The oriented C model is called using *Iqabc(qa, qb, qc, par1, par2, ...)* where 
    552547*par1*, etc. are the parameters to the model.  If the shape is rotationally 
    553548symmetric about *c* then *psi* is not needed, and the model is called 
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