Initializing help system before first use

# constraint.getCallbackDual

Purpose
Returns the dual value for this constraint from the solution associated with the current callback.
Topic areas
Solution, Callback, Optimizer
Synopsis
`dual = constraint.getCallbackDual()`
Return value

dual | The dual value of the constraint.

Further information
1. The function always returns data in the input space, even if the problem is currently in presolved state.
2. See problem.getCallbackSolution for a list of callbacks where this function can be called. Note that a dual solution is not available in all contexts where a primal solution is available.
Related topics
var.getCallbackSolution, constraint.getCallbackSlack, var.getCallbackRedCost, problem.getCallbackPresolveDuals, constraint.getDual.
Parent Topic Xpress constraint object methods

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