10.123 WATCH—A beam property/motion monitor–allowed modes are centroid, parameter, coordinate, and fft.

A beam property/motion monitor–allowed modes are centroid, parameter, coordinate, and fft.
Parallel capable? : yes
GPU capable? : no
Back-tracking capable? : yes






Parameter Name UnitsType Default

Description






FRACTION double 1

fraction of particles to dump (coordinate mode)






START_PID long -1

starting particleID for particles to dump






END_PID long -1

ending particleID for particles to dump






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 STRINGcoordinates

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 short 1

include x data in coordinate mode?






Y_DATA short 1

include y data in coordinate mode?






LONGIT_DATA short 1

include longitudinal data in coordinate mode?






EXCLUDE_SLOPES short 0

exclude slopes in coordinate mode?






FLUSH_INTERVAL long 100

file flushing interval (parameter or centroid mode)






SPARSE_INTERVAL long 1

interval for particle output (coordinate mode)






DISABLE short 0

If nonzero, no output will be generated.






USE_DISCONNECT short 0

If nonzero, files are disconnected between each write operation. May be useful for parallel operation. Ignored otherwise.






WATCH continued

A beam property/motion monitor–allowed modes are centroid, parameter, coordinate, and fft.






Parameter Name UnitsType Default

Description






INDEX_OFFSET long 0

Offset for file indices for sequential file naming.






REFERENCE_FREQUENCY double-1

If non-zero, the indicated frequency is used to define the bucket center for purposes of computing time offsets.






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.

Notes:

  1. 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.
  2. This element can adversely affect parallel efficiency. Use of the START_PASS, END_PASS, INTERVAL, and FLUSH_INTERVAL options can help reduce the impact. Also, particle output is the most expensive, by far.

WIGGLER