SPEX Reference manual (PDF) - SRON

2.29 System 43
Warning: One should first rebin the data, before running syserr. Run syserr however before fitting the
data or finding errors on the fit.
Warning: Running syserr multiple times will increase the error every time. If the input to syserr is
wrong one should restart SPEX and rerun syserr with the correct values to calculate the total error correctly.
Syntax
The following syntax rules apply:
syserr #i: #r1 #r2 - The shortest version of this command. #i: is the range in data channels for
which the systematic error is to be calculated and added (in quadrature) to the Poissonian error. #r1 is
then the the relative systematic error due to the source and #r2 the relative systematic error due to the
background.
syserr [instrument #i1:] [region #i2:] #i3: #r1 #r2 - In this syntax one can also specify the
instrument and the region one wants to calculate the combined error for. Both can be ranges as well.
#i3: has the same role as #i: in the above command, and #r1 and #r2 are the same as above.
syserr [instrument #i1:] [region #i2:] #i3: #r1 #r2 [unit #a] - Exact same command as
above, except that now the data range (#i3:) for which the errors are to be calculated are given in units
different than data channels. These units can be Å (ang), eV (ev), keV (kev), Rydbergs (ryd), Joules (j),
Hertz (hz) and nanometers (nm). This is the most general command.
Examples
syserr 1:100000 0.3 0.5 - Calculates the combined Poissonian and systematic error for data channels
1:100000, where the fraction of the systematic error of the source is 0.3 and the background is 0.5.
syserr 0:2000 0.3 0.5 unit ev - The same as the above command, expect that now the error calculation
is performed between 0 and 2000 eV instead of data channels.
syserr instrument 2 region 1 0:2000 0.3 0.5 unit ev - The same as the above command, but
now the error calculation is only performed for the data set from the second instrument and the first
region thereof.
2.29 System
Overview
Sometimes it can be handy if SPEX interacts with the computer system, for example if you run it in
command mode. You might want to check the existence of certain file, or run other programs to produce
output for you, and depending on that output you want to continue SPEX.
Therefore there is an option to execute any shell type commands on your machine, using the fortran ”call
system” subroutine.
Another useful goody is the possibility to stop SPEX automatically if you find some condition to occur;
this might be useful for example if you have a program running that calls SPEX, and depending on the
outcome of SPEX you might want to terminate the execution. This is achieved in SPEX by testing for
the existence of a file with a given filename; if the file exists, SPEX stops immediately execution and
terminates; if the file does not exist, SPEX continues normally.
Syntax
The following syntax rules apply: