7.13 change_start
- type: action command.
- function: change the starting point in a lattice
- sequence: must precede run_setup.
- Command syntax, including use of equations and subcommands, is discussed in 7.2.
&change_start
STRING element_name = NULL;
long element_occurence = 1;
long ring_mode = 0;
long delta_position = 0;
&end
- element_name — Name of the element where the lattice will start, which implies removing
all elements upstream of the named element. If the element occurs more than once, the first
instance is used. The named element will be the first element in the lattice.
- element_occurence — Occurrence number of the element to use.
- ring_mode — If nonzero, the ring structure of the lattice is preserved by moving the elements
upstream of the named element to the end of the lattice.
- delta_position — The number of elements before (if negative) or after (if positive) by which
to offset the end position.