Command-line program for Jemian/Lake desmearing¶
jldesmear.jl_api.traditional is the main program to run desmearing.
It provides the same command-line interface as its FORTRAN and C predecessors.
The main command-line interface is started with a Python command such as:
import jldesmear.api
jldesmear.jl_api.traditional.command_line_interface()
traditional user interface documentation¶
Iterative desmearing technique of Lake to small-angle scattering data
Credits¶
| author: | Pete R. Jemian |
|---|---|
| organization: | Late-Nite(tm) Software |
| note: | lake.py was derived from lake.c in 2009 |
| note: | lake.c was derived from the FORTRAN program Lake.FOR |
| note: | Lake.FOR 25 May 1991 |
| see: | P.R.Jemian,; Ph.D. thesis, Northwestern University (1990). |
| see: | J.A. Lake; ACTA CRYST 23 (1967) 191-194. |
Overview¶
This program applies the iterative desmearing technique of Lake to small-angle scattering data. The way that the program works is that the user selects a file of data (x,y,dy) to be desmeared. If a file was not chosen, the program will end. Otherwise the user is then asked to specify the slit-length (in the units of the x-axis); the x at which to begin fitting the last data points to a power-law of x, the output file name, and the number of iterations to be run. Then the data file is opened, the data is read, and the data file is closed. The program begins iterating and shows an indicator of progress on the screen in text format.
| caution: | It is important to only provide smeared data (data that has not been desmeared, even partially) to this program as you will see. The iterative desmearing technique should be made to iterate with the original, smeared data and subsequent trial solutions of desmeared data. |
|---|
The integration technique used by this program to smear the data
is the trapezoid-rule where the step-size is chosen by the
spacing of the data points themselves. A linear
interpolation of the data is performed. To avoid truncation
effects, a power-law extrapolation of the intensity
is made for all values beyond the range of available
data. This region is also integrated by the trapezoid
rule. The integration covers the region from l = 0
up to l = lo. (see module smear).
This technique allows the slit-length weighting function
to be changed without regard to the limits of integration
coded into this program.
Other deconvolution methods¶
These authors have presented desmearing/deconvolution methods that were considered or reviewed in the development of this work.
- O. Glatter. ACTA CRYST 7 (1974) 147-153.
- W.E. Blass & G.W.Halsey. (1981) “Deconvolution of Absorption Spectra.” New York City: Academic Press
- P.A. Jansson. (1984) “Deconvolution with Applications in Spectroscopy.” New York City: Academic Press.
- G.W.Halsey & W.E. Blass. (1984) “Deconvolution Examples” in “Deconvolution with Applications in Spectroscopy.” Ed. P.A. Jansson. (see above)
Source Code Documentation¶
-
jldesmear.jl_api.traditional.GetInf(params)[source]¶ Get information about the desmearing parameters. This is designed to be independent of wavelength or radiation-type (i.e. neutrons, X rays, etc.)
Parameters: params (obj) – Desmearing parameters object Returns: params or None
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jldesmear.jl_api.traditional.callback(dsm)[source]¶ this function is called after every desmearing iteration from
desmear.Desmearing.traditional()Parameters: dsm (obj) – Desmearing object Returns: should desmearing stop? Return type: bool
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jldesmear.jl_api.traditional.command_line_interface()[source]¶ SAS data desmearing, by Pete R. Jemian Based on the iterative technique of PR Jemian and JA Lake. P.R.Jemian,; Ph.D. thesis, Northwestern University (1990). J.A. Lake; ACTA CRYST 23 (1967) 191-194.
$Id$ Desmear using the same command line interface as the FORTRAN & C predecessors.