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IF_THEN - Conditional execution of operations (Scripting operation)

(09/16/06)

PURPOSE

Allow conditional execution of sections of the SPIDER operation stream, depending on the logical value of an expression. Modeled after the FORTRAN 'IF...ELSEIF...ELSE...ENDIF'.

SEE ALSO

ELSEIF_THEN [Conditional execution of operations (Scripting operation)]
ELSE [Conditional execution of operations (Scripting operation)]
IF [Conditional expression execution (Scripting operation)]
IF_GOTO [Conditional jump (Scripting operation)]

USAGE

.OPERATION: IF(<EXP>.<LC>.<EXP>) THEN
~~~~~~~
~~~~~~~
ENDIF

Where:

  1. <EXP> is an expression
  2. <LC> is a logical comparator. The following comparators are allowed:
  3. EQ equal
    NE not equal
    GT greater
    GE greater/equal
    LT less
    LE less/equal

EXAMPLES:

IF([ysize].GE.15) THEN
AC
input001
output001
ENDIF

IF([ysize].LT.15) THEN
AC
input001
output001
ELSEIF ([ysize].LT.150) THEN
AC
input001
output002
ELSE
AC
input001
output003
ENDIF

NOTES

  1. Nesting of IF_THEN..ELSE...ENDIF is limited to MAXPRC levels. See: CMLIMIT.INC for current value of MAXPRC.

  2. For every 'IF_THEN' there must be a closing ENDIF!

  3. There is no '.AND.' comparator.

  4. The operation 'ELSEIF' was not available prior to SPIDER release 15.0.

  5. Implemented by: ArDean Leith

SUBROUTINES

LOGIFQ

CALLER

SPIDER

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