Elegant users forum

Hi Michael,

Is there a command to output the last entry of a specified column in an SDDS file (e.g. you want the exit beta functions from a .twi file)? I have no doubt that this can be done, but a from a quick glance through the OAG manual, it wasn't clear to me how to do it.

Thanks,
chris

Chris,

You need to use several commands togther. One way using SDDS tools only is

sddsprocess data.twi -clip=0,1,invert -pipe=out | sdds2stream -pipe -column=betax

Another way is

sdds2stream data.twi -column=betax | tail -1

If you are using the data inside elegant in an optimization term, you can use rpn_load. If you want to continue beta function calculations from a previous segment, you can use the reference_file feature of twiss_output.

--Michael