Content-type: text/html Man page of X-GEN


Section: X-GEN Commands (1)
Updated: April 2005
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X-GEN - strategy  


strategy [-a] [-yval] [resmin] [resmax]  


strategy examines the sample and detector parameters contained in a UPARAMS file and uses them to calculate and plot an appropriate data acquisition strategy. Currently the program works only for simple geometries, i.e. either an omega rotation or a phi rotation with chi or kappa equal to zero.

The output is a matrix showing the range of phi required to achieve various levels of data completeness for each starting value of phi. Thus if it determines that 99% completeness can be obtained for a start value of phi equal to 68 degrees only if we cover 120 degrees (68-188), then the matrix element in the phi=68 row and the 99% completeness column will be 120. By default it examines phi values on a 4 degree granularity (0, 4, 8, ...) and reports on the delta-phi required for completeness levels of 0.50, 0.75, 0.90, 0.94, 0.99, 0.995, 0.999, and 1.0000. For each level of completeness it reports relative to both achievable reflections and total reflections; thus if we can only achieve 98.1% completeness (a typical value, given Lorentz exclusions), then the top of the table will look like  

Symmetry-transformed reflections under scrutiny:

predictable unobtainable
1801 97285
Summary of strategy calculation
| Deltaphi required for the fractional completeness of:
Start phi | 0.5000 0.7500 0.9000 0.9400 0.9700 0.9900 0.9950 0.9990 1.0000
| 0.4907 0.7361 0.8833 0.9226 0.9520 0.9717 0.9766 0.9805 0.9815
0.00 |
24.00 36.00 68.00 96.00 132.00 196.00 228.00 332.00 360.00
4.00 |
20.00 36.00 68.00 100.00 136.00 196.00 224.00 332.00 360.00

where the top row of completeness values (0.5000, 0.7500, . . . ) correspond to the fraction of achievable reflections, whereas the next row (0.4907, 0.7361, 0.8833 ...) corresponds to the fraction of total reflections.

The output of "strategy" is written to the log file and to a file called strategy.out in the current directory. The strategy.out version is designed to be compatible with BLT-based or WxPython-based plotting packages.

-a If specified, strategy will treat a reflection as
unobtainable _only_ if its Lorentz correction is truly zero. Otherwise reflections will be treated as unobtainable if their Lorentz correction is smaller than a cutoff, by default 0.03.
If specified, the Lorentz correction cutoff (see above) is set to the value <val>.
This specifies a high-resolution cutoff, such that reflections at higher resolution than this cutoff (smaller D spacing) will not be predicted. Setting this parameter to a more restrictive value than the edge of the detector will make the program run faster.
This specifies the low-resolution cutoff below which reflections will not be predicted.


strategy -y0.01 50 1.8
Perform a strategy calculation with the
Lorentz correction cutoff set to 0.01 over a resolution range of 50 to 1.8 Angstroms:


Report bugs to Andy Howard at or 312-567-5881.  


Copyright © 2002, Illinois Institute of Technology. See the file 'LICENSE' for information on usage and redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES



Symmetry-transformed reflections under scrutiny:

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Time: 02:08:09 GMT, October 03, 2005