&error_element STRING name = NULL; STRING element_type = NULL; STRING item = NULL; STRING type = "gaussian"; double amplitude = 0.0; double cutoff = 3.0; long bind = 1; long bind_number = 0; longn bind_across_names = 0; long post_correction = 0; long fractional = 0; long additive = 1; long allow_missing_elements = 0; STRING after = NULL; STRING before = NULL; &end
name-- The possibly wildcarded name of the elements for which errors are being specified.
element_type-- An optional, possibly wildcarded string giving the type of elements to which the errors should be applied. E.g.,
element_type=*MON*would match all beam position monitors. If this item is given, then
namemay be left blank.
item-- The parameter of the elements to which the error pertains.
type-- The type of random distribution to use. May be one of ``uniform'', ``gaussian'', or ``plus_or_minus''. A ``plus_or_minus'' error is equal in magnitude to the amplitude given, with the sign randomly chosen.
amplitude-- The amplitude of the errors.
cutoff-- The cutoff for the gaussian random distribution in units of the amplitude. Ignored for other distribution types.
bind_across_names-- These parameters control ``binding'' of errors among elements, which means assigning the same error contribution to several elements. This occurs if
bindis nonzero, which it is by default! If
bindis negative, then the sign of the error will alternate between successive elements.
bind_numbercan be used to limit the number of elements bound together. In particular, if
bind_numberis positive, then a positive value of
bind_numbersuccessive elements having the same name will have the same error value. Finally, by default, elegant only binds the errors of objects having the same name, even if they are assigned errors by the same
error_elementcommand (i.e., through a wildcard
bind_across_namesis nonzero, then binding is done even for elements with different names.
post_correction-- A flag indicating whether the errors should be added after orbit, tune, and chromaticity correction.
fractional-- A flag indicating whether the errors are fractional, in which case the amplitude refers to the amplitude of the fractional error.
additive-- A flag indicating that the errors should be added to the prior value of the parameter. If zero, then the errors replace the prior value of the parameter.
allow_missing_elements-- A flag indicating that execution may continue even if no matching elements are found.
after-- The name of an element. If given, the error is applied only to elements that follow the named element in the beamline.
before-- The name of an element. If given, the error is applied only to elements that precede the named element in the beamline.