LOCUS--Display and Analyze Database Data

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LOCUS--Display and Analyze Database Data

LOCUS is the PPL standard utility for manipulating and displaying databases . An example of its use is the determination of scaling laws. To do this you can enter and modify data, define subsidiary variables as arbitrary functions of original data, plot such variables, and perform linear and multiple linear regression analysis. A cursor option in LOCUS lets you see parameters that correspond to points on a graph. This is useful for identifying the shot number of selected points, for example. The LOCUS document is available in hardcopy or via the TFTR documents Web page.

There are two implementations of LOCUS--one uses INGRES databases and the other VMS ISAM files. You can use either implementation. If you want to share your data with other people at PPL, the INGRES version is recommended. If you want to transport your database to another VMS system that doesn't have INGRES, then use the ISAM version. There is also a program, INGRATE, that converts a LOCUS ISAM file to an INGRES database table.

TFTRLOG sets up the INGRES version of LOCUS. If you want the ISAM version, do $ SETUP LOCUS ISAM RESET after calling TFTRLOG. (RESET is necessary to force the new definition.) An extensive users' manual is available. $ HELP LOCUS tells how to get it.

The following session shows how to graph the plasma current vs the average density for shots since 73000 with beam power greater than 10MW from the table ALLSHOTS in the TFTR database.

    $ LOCUS
    <0=SD;> Select database and tables <DB>:
                DB TFTR              !TFTR Database
                PT ALLSHOTS ;;       !ALLSHOTS Parameter Table
    <1=MO;> Plot,Regress,Surface,PRint,Edit,SQL? <PL>:
                PL                   !Select Plot
    <2=N;> Set: Y,X,C,S,G,G+,K,SO,J,Mu,An,Ou,Ex,Re? <G>:
                Y IP                 !IP is Y axis
    <2=N;> Set: Y,X,C,S,G,G+,K,SO,J,Mu,An,Ou,Ex,Re? <Y>:
                X NEBAR              !NEBAR is X axis
    <2=N;> Set: Y,X,C,S,G,G+,K,SO,J,Mu,An,Ou,Ex,Re? <X>:
                C SHOT>73000 BP>10;  !set Constraints
    <2=N;> Set: Y,X,C,S,G,G+,K,SO,J,Mu,An,Ou,Ex,Re? <C>:
                ;                    !end setup, generate plot

At any prompt, typing <RETURN> gives an explanatory list of the possible responses; e.g., at the <2=N;> level prompt:

    \* Options are:
     1) Y < >
     2) X < >
     3) Constraints < >
     4) Symbols < >
          ...

You can enter either the option number or enough of the keyword to uniquely identify the option (the part displayed in capital letters). LOCUS remembers the previous response to each option and shows this in the prompt; to retain this value, type a comma.

The information in the angle brackets indicates the current level. In general, \ backs up a level. In particular, \MO backs up to the Main Option menu. At any level, you can type \X to exit, ? to see the TK user interface commands, or \H for help. LOCUS is maintained by Dick Wieland. is maintained by Jane Murphy and Dick Wieland.

Next: MINGL--Database Utilities Up: How to Look at Previous: TASKPRINT and OPERPRINT--Shot Commentary

Marilee Thompson
Fri Jul 11 11:22:04 EDT 1997