WATCH

A beam property/motion monitor-allowed modes are centroid, parameter, coordinate, and fft.
Parallel capable? : yes

Parameter Name	Units	Type	Default	Description
FRACTION		double	1	fraction of particles to dump (coordinate mode)
INTERVAL		long	1	interval for data output (in turns)
START_PASS		long	0	pass on which to start
END_PASS		long	-1	pass on which to end (inclusive). Ignored if negative.
FILENAME		STRING		output filename, possibly incomplete (see below)
LABEL		STRING		output label
MODE		STRING	coordinates	coordinate, parameter, centroid, or fft. For fft mode, you may add a space and a qualifer giving the window type: hanning (default), parzen, welch, or uniform.
X_DATA		long	1	include x data in coordinate mode?
Y_DATA		long	1	include y data in coordinate mode?
LONGIT_DATA		long	1	include longitudinal data in coordinate mode?
EXCLUDE_SLOPES		long	0	exclude slopes in coordinate mode?
FLUSH_INTERVAL		long	100	file flushing interval (parameter or centroid mode)
DISABLE		long	0	If nonzero, no output will be generated.
USE_DISCONNECT		long	0	If nonzero, files are disconnected between each write operation. May be useful for parallel operation. Ignored otherwise.
INDEX_OFFSET		long	0	Offset for file indices for sequential file naming.
GROUP		string	NULL	Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup

The output filename may be an incomplete filename. In the case of the WATCH point element, this means it may contain one instance of the string format specification ``%s'' and one occurence of an integer format specification (e.g., ``%ld''). elegant will replace the format with the rootname (see run_setup) and the latter with the element's occurrence number. For example, suppose you had a repetitive lattice defined as follows:

W1: WATCH,FILENAME=''%s-%03ld.w1''
Q1: QUAD,L=0.1,K1=1
D: DRIFT,L=1
Q2: QUAD,L=0.1,K1=-1
CELL: LINE=(W1,Q1,D,2*Q2,D,Q1)
BL: LINE=(100*CELL)

The element W1 appears 100 times. Each instance will result in a new file being produced. Successive instances have names like ``rootname-001.w1'', ``rootname-002.w1'', ``rootname-003.w1'', and so on up to ``rootname-100.w1''. (If instead of ``%03ld'' you used ``%ld'', the names would be ``rootname-1.w1'', ``rootname-2.w1'', etc. up to ``rootname-100.w1''. This is generally not as convenient as the names don't sort into occurrence order.)

The files can easily be plotted together, as in

% sddsplot -column=t,p *-???.w1 -graph=dot -separate 

They may also be combined into a single file, as in

% sddscombine *-???.w1 all.w1 

In passing, note that if W1 was defined as

W1: WATCH,FILENAME=''%s.w1''

or

W1: WATCH,FILENAME=''output.w1''

only a single file would be produced, containing output from the last instance only.

N.B.: confusion sometimes occurs about some of the quantities related to the s coordinate in this file when in parameter mode. Please see Section 4 above.