[9a11937] | 1 | """ |
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| 2 | P(r) inversion for SANS |
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| 3 | """ |
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| 4 | ## \mainpage P(r) inversion for SANS |
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| 5 | # |
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| 6 | # \section intro_sec Introduction |
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| 7 | # This module provides calculations to transform scattering intensity data |
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| 8 | # I(q) into distance distribution function P(r). A description of the |
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| 9 | # technique can be found elsewhere [1-5]. The module is useable as a |
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| 10 | # standalone application but its functionality is meant to be presented |
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| 11 | # to end-users through the user interface developed as part of the SANS |
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| 12 | # flagship application. |
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| 13 | # |
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| 14 | # Procedure: We will follow the procedure of Moore [1]. |
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| 15 | # |
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| 16 | # [1] P.B. Moore, J.Appl. Cryst (1980) 13, 168-175. |
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[896abb3] | 17 | # |
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[9a11937] | 18 | # [2] O. Glatter, J.Appl. Cryst (1977) 10, 415-421. |
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[896abb3] | 19 | # |
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[9a11937] | 20 | # [3] D.I. Svergun, J.Appl. Cryst (1991) 24, 485-492. |
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[896abb3] | 21 | # |
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[9a11937] | 22 | # [4] D.I. Svergun, J.Appl. Cryst (1992) 25, 495-503. |
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[896abb3] | 23 | # |
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[9a11937] | 24 | # [5] S. Hansen and J. Skov Pedersen, J.Appl. Cryst (1991) 24, 541-548. |
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| 25 | # |
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[ffca8f2] | 26 | ## \subsection class Class Diagram: |
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| 27 | # The following shows a partial class diagram with the main attributes and methods of the invertor. |
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| 28 | # |
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| 29 | # \image html architecture.png |
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[9a11937] | 30 | # |
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| 31 | # \section install_sec Installation |
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| 32 | # |
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| 33 | # \subsection obtain Obtaining the Code |
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| 34 | # |
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| 35 | # The code is available here: |
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| 36 | # \verbatim |
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| 37 | #$ svn co svn://danse.us/sans/pr_inversion |
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| 38 | # \endverbatim |
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| 39 | # |
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| 40 | # \subsection depends External Dependencies |
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| 41 | # scipy, numpy, pylab |
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| 42 | # |
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| 43 | # \subsection build Building the code |
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| 44 | # The standard python package can be built with distutils. |
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| 45 | # \verbatim |
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| 46 | #$ python setup.py build |
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| 47 | #$ python setup.py install |
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| 48 | # \endverbatim |
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| 49 | # |
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| 50 | # |
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[896abb3] | 51 | # \subsection Tutorial |
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| 52 | # To create an inversion object: |
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| 53 | # \verbatim |
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| 54 | #from sans.pr.invertor import Invertor |
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| 55 | # invertor = Invertor() |
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| 56 | # \endverbatim |
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| 57 | # |
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| 58 | # To set the maximum distance between any two points: |
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| 59 | # \verbatim |
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| 60 | # invertor.d_max = 160.0 |
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| 61 | # \endverbatim |
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| 62 | # |
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| 63 | # To set the regularization constant: |
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| 64 | # \verbatim |
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| 65 | # invertor.alpha = 0.0007 |
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| 66 | # \endverbatim |
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| 67 | # |
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| 68 | # To set the q, I(q) and error on I(q): |
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| 69 | # \verbatim |
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| 70 | # invertor.x = q_vector |
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| 71 | # invertor.y = Iq_vector |
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| 72 | # invertor.err = dIq_vector |
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| 73 | # \endverbatim |
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| 74 | # |
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| 75 | # To perform the inversion. In this example, we choose |
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| 76 | # a P(r) expension wit 10 base functions. |
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| 77 | # \verbatim |
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| 78 | # c_out, c_cov = invertor.invert(10) |
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| 79 | # \endverbatim |
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| 80 | # The c_out and c_cov are the set of coefficients and the covariance |
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| 81 | # matrix for those coefficients, respectively. |
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| 82 | # |
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[ffca8f2] | 83 | # To get P(r): |
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| 84 | # \verbatim |
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| 85 | # r = 10.0 |
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| 86 | # pr = invertor.pr(c_out, r) |
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| 87 | # \endverbatim |
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| 88 | # Alternatively, one can get P(r) with the error on P(r): |
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| 89 | # \verbatim |
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| 90 | # r = 10.0 |
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| 91 | # pr, dpr = invertor.pr_err(c_out, c_cov, r) |
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| 92 | # \endverbatim |
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| 93 | # |
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| 94 | # To get the output I(q) from the set of coefficients found: |
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| 95 | # \verbatim |
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| 96 | # q = 0.001 |
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| 97 | # iq = invertor.iq(c_out, q) |
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| 98 | # \endverbatim |
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| 99 | # |
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[9a11937] | 100 | # Examples are available as unit tests under sans.pr_inversion.test. |
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| 101 | # |
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| 102 | # \section help_sec Contact Info |
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| 103 | # Code and Documentation produced as part of the DANSE project. |
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| 104 | |
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| 105 | __author__ = 'University of Tennessee' |
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