EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

Edit a Beam Line Sequence

With the help of the commands explained below, a sequence may be modified in many ways: the starting point can be moved to another place; the order of elements can be inverted; elements can be inserted one by one, or as a whole group with one single command; single elements, or classes thereof can be removed; elements can be replaced by others; finally, the sequence can be "flattened", i.e. all inserted sequences are replaced by their actual elements, such that a flattened sequence contains only elements. It is good practice to add a flatten; statement at the end of a seqedit operation to ensure a fully operational sequence. And this is particularly useful for the save command to properly save shared sequences and to write out in MAD-8 format.

• SEQEDIT

  seqedit, sequence=s_name;
  

  selects the sequence named for editing. The editing is performed on the non-expanded sequence; after having finished the editing, one has to re-expand the sequence if necessary.

• EXTRACT

  extract,sequence=s_name,from=MARKER_1,to=MARKER_2,newname=p;
  

  From the sequence named "s_name" is extracted a new sequence with name "p" starting from MARKER_1 and ending at MARKER_2. The new sequence "p" can be USEd as any other sequence. It is declared as "shared" and can therefore be combined E.G. into the cycled original sequence.

• FLATTEN

  flatten;
  

  This command includes all sequences in the sequence being edited, if any. The resulting sequence contains only elements.

• INSTALL

  install, element=name,class=class_name,at=real,from=place|selected;
  

  where the parameters have the following meaning:
  • element: name of the (new) element to be inserted (mandatory)
  • class: class of the new element to be inserted (mandatory)
  • at: position where the element is to be inserted; if no "from" is given,this is relative to the start of the sequence. If "from" is given, it is relative to the position specified there.
  • from:either a place (i.e. the name(+occurrence count) of an element already existing in the sequence, e.g. mb[15], or mq.a..i1..4 etc.; or the string "selected"; in this latter case an element of the type specified will be inserted behind all elements in the sequence that are currently selected by one or several SELECT commands of the type

    select,flag=seqedit,class=.., pattern=.., range=..;
    

  • Attention: No element definitions inside seqedit.

• MOVE

  move, element=name|selected,by=real,to=real,from=place;
  

  • element: name of the existing element to be moved, or "selected", in which case all elements from existing SELECT commands will be moved; in the latter case, "by" must be given.
  • by: amount by which the element(s) is/are to be moved; no "to" nor "from" in this case.
  • to: position to which the element has to be moved; if no from, then this is relative to the start of the sequence; otherwise, it is relative to the place given in "from".
  • from: place in the sequence with respect to which the element is to be positioned.

• REMOVE

  remove, element=name|selected;
  

  • element: name of the existing element to be removed, or "selected", in which case all elements from existing SELECT commands will be removed.
  • Attention: It is a bad idea to remove all markers from a sequence! In particular the "start=" marker and the new markers added by "cycle" must never be removed from a sequence.

• CYCLE

  cycle,start=place;
  

  This makes the sequence start at the place given, which must be a marker.

  In the case there is a shared sequence in the used sequence, the command FLATTEN has to be used before the command CYCLE. Example:

  flatten ; cycle,start=place;

• REFLECT

  reflect;
  

  This inverts the order of element in the sequence, starting from the last element.

  If there are shared sequences inside the USEd sequence, the command FLATTEN must be used before the command REFLECT. Alternatively each shared sequence must first be reflected. Example:

  flatten ; reflect;

• REPLACE

  replace,element=name1|selected,by=name2;
  

  Element with name1 is replaced by element with name2. If name1 is "selected", then all elements selected by SELECT commands will be replaced by the element name2.

• ENDEDIT

  endedit;
  

  terminates the sequence editing process. The nodes in the sequence are renumbered according to their occurrence which might have changed during editing.
  hansg, June 17, 2002