AFSTATS - INTENSITY STATISTICS
==============================


INTRODUCTION
 
The program AFSTATS is used to read in data from a Laue .afout file and
give distributions of reflections with respect to wavelength or d-spacing.
Graphical output and a log file are produced. The program is designed to
aid the appropriate choice of the Laue 'soft limits' lambda-min and dmin.
The program was written by M.M. Harding, University of Liverpool.
 
 
List of sections:
 
   Data Control Cards
   Input and Output Files
   Running the Program
   Notes
   Printer Output
   Error Messages
   Program Function
   Examples
 
DATA CONTROL CARDS
 
The program is run interactively and uses the following question and answer
sequence.
 
 
Enter name of input file:
 
   The reply is the name of the .afout file containing the Laue data to be
   analysed.
 
Name of output file:
 
   The reply is the name of the output log file.
 
Statistics on wavelength (1) or d-spacing (2):
 
   The reply is '1' if intensity statistics as a function of wavelength are
   required.
 
   The reply is '2' if intensity statistics as a function of d-spacing are
   required.
 
 
One of the two following prompts will then be output depending on the reply
to the previous question
 
 
Enter wvmin, wvmax and numbins:
 
   wvmin is the minimum wavelength value in Angstroms for the wavelength
   range to be examined.
 
   wvmax is the maximum wavelength value in Angstroms for the wavelength
   range to be examined.
 
   numbins is the number of bins for the statistics.
 
Enter dmin, dmax and numbins:
 
   dmin is the minimum d-spacing value in Angstroms for the d-spacings
   range to be examined.
 
   dmax is the maximum d-spacing value in Angstroms for the d-spacing range
   to be examined.
 
   numbins is the number of bins for the statistics.
 
Use I > const * sigma(I) ; give const:
 
   The reply is a constant 'sigtest' which allows for the selection of
   reflections for which I > sigtest*sigma(I).
 
Output nbin (n) of FFmean (f):
 
   Give a reply of 'n' to select statistics giving the numbers of
   reflections in each range for the graphical output.
 
   Give a reply of 'f' to select statistics giving the F**2 mean value in
   each range for the graphical output.
 
Output graph (g) or histogram (h):
 
   Give a reply of 'g' to output the results to the graphics screen in
   'graph' form.
 
   Give a reply of 'h' to output the results to the graphics screen in
   'histogram' form.
 
Is this a unix xterm window (y/n):
 
   Reply 'y' if an X-windows display is being used with an 'xterm' window;
   otherwise reply 'n'.
 
Input title for plot (max 20 chars):
 
   The reply is a title for the plot up to 20 characters in length.
 
Input label for x-axis (max 20 characters):
 
   The reply is a label for the x-axis (wavelength of d-spacing) up to 20
   characters in length.
 
Input label for y-axis (max 20 characters):
 
   The reply is a label for the y-axis (numbers of reflections or F**2
   mean) up to 20 characters in length.
 
Do you want hard copy plot (y/n):
 
   The reply is 'y' if a hard copy plot is required or 'n' if it is not.
 
Name of output Postscript file:
 
   This prompt is only output if hard copy was requested. The reply gives
   the required name for the output Postscript file.
 
 
 
 
INPUT AND OUTPUT FILES
 
The input file is:
 
   A Laue .afout file from the program AFSCALE. The program reads this in
   free format.
 
Output file:
 
   A log file containing the statistics.
 
 
 
RUNNING THE PROGRAM
 
The program may be run via the command
 
'laue afstats'
 
 
NOTES
 
The graphics are for a T4010 (tektronix type) terminal emulation. This may,
if required, be an 'xterm' window on an X-windows display.
 
 
PRINTER OUTPUT
 
The program outputs a log file with the following information:
 
Heading with name of input .afout file.
 
Sigma cutoff being used.
 
Number of reflections read from input file.
 
Number of reflections passing the sigma cutoff test.
 
Table of statistics giving the wavelength/d-spacing ranges, the numbers of
reflections and the Imean values for the bins.
 
 
ERROR MESSAGES
 
**Error** file does not exist
 
**Error** Unable to open output file
 
 
PROGRAM FUNCTION
 
The program AFSTATS was written originally by Marjorie Harding with Ian
Dodd. Graphical output was added by Paul Carr. The program reads in data
from a Laue .afout file and gives distributions of reflections with respect
to wavelength or d-spacing. The program is designed to aid the appropriate
choice of the Laue 'soft limits' lambda-min and dmin. For the graphical
output it has options for giving the numbers of reflections or F**2 mean
values in each range. Thr graphical output can be in 'graph' or 'histogram'
form and hard copy may be produced via a Postscript output file. A log file
containing the required statistics is also produced.
 
 
EXAMPLES
 
 
Enter name of input file: pf1_ln.afout
Name of output file: afstats.log
Statistics on wavelength (1) or d-spacing (2): 1
Enter wvmin, wvmax, numbins: 0.5 1.5 10
Use I > const * sigma(I)  ; give const: 3.0
Output nbin (n) of FFmean (f): f
Output graph (g) or histogram (h): g
Is this a unix xterm window (y/n): n
Input title for plot (max 20 chars): Lambda Analysis
Input label for x-axis (max 20 characters): lambda
Input label for y-axis (max 20 characters): nrefl
Do you want hard copy plot (y/n): y
Name of output Postscript file: afstats.ps