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Altair FlowTracer Developer Guide
Flow Description Language (FDL)
J versus T
In FDL there are two procedures that can be used to add a job to a flow: T and J. Which one should you use?

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- Flow Description Language (FDL)
  - Flow Language Procedures
  - FDL Procedures Reference
  - J versus T
    In FDL there are two procedures that can be used to add a job to a flow: T and J. Which one should you use?
  - Build Flows with vovbuild
  - Conflicts in vovbuild
  - Use O_CONFLICT to Choose Behavior in Case of Output Conflict
  - vovbuild Argument Parsing
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  - Dependencies in FDL
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  - vtk_transition_add
  - Difference Between E and ves
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- Flow Library
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- Files, Equivalences, Exclusions
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- Makefile Conversion
- Advanced Tasker Topics
- Resource Management
  The Resource Map Set represents the collection of resource maps that have been assigned to a project and the constraints associated with such resources.
- CGI Interface
- Events
  Every change in the trace is recorded as an event, which is then sent to all clients that subscribe to them.
- Miscellaneous

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J versus T

In FDL there are two procedures that can be used to add a job to a flow: T and J. Which one should you use?

The difference between J and T is that J evaluates the capsule for the tool while T does not. If the tool you are adding to the flow has no capsule, there is no difference between J and T. On the other hand, if a capsule is available, J will give you a more compact flow description. Even with a capsule, you may want to consider using T, with some explicit I's and O's in order to build the flow more quickly.


Procedure	Advantages	Disadvantages
J (with capsule evaluation)	More compact flow description. Same as T if there is no capsule.	Requires a capsule to be effective. Capsule evaluation may be slow.
T (no evaluation of capsule)	Faster evaluation.	Must declare explicit I's and O's dependencies to avoid false job executions.

For example, consider the tool cp which has a capsule ($VOVDIR/tcl/vtcl/capsules/vov_cp.tcl). The two following flow descriptions are equivalent:

# This uses the capsule vov_cp.tcl
J vw cp aa bb

# This instead does not use the capsule.
T vw cp aa bb
I aa
O bb