QPSMonitorSet

Sets an ADDITIONAL function to be called at every iteration to monitor the residual/error etc.

PetscErrorCode  QPSMonitorSet(QPS qps,PetscErrorCode (*monitor)(QPS,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))

Logically Collective on QPS

	qps	- iterative context obtained from QPSCreate()
	monitor	- pointer to function
	mctx	- [optional] context for private data for the monitor routine (use NULL if no context is desired)
	monitordestroy	- [optional] routine that frees monitor context (may be NULL)

    monitor (QPS qps, PetscInt it, PetscReal rnorm, void *mctx)

	qps	- iterative context obtained from QPSCreate()
	it	- iteration number
	rnorm	- 2-norm of the residual (more general, a vector whose norm determines convergence, such as a projected gradient for QPSMPGP)
	mctx	- optional monitoring context, as set by QPSMonitorSet()

	-qps_monitor	- sets QPSMonitorDefault()
	-qps_monitor_cost	- sets QPSMonitorCostFunction()
	-qps_monitor_cancel	- cancels all monitors that have been hardwired into a code by calls to QPSMonitorSet(), but does not cancel those set via the options database.

The default is to do nothing. To print the residual, use QPSMonitorDefault() as the monitoring routine, with a null monitoring context.

Several different monitoring routines may be set by calling QPSMonitorSet() multiple times; all will be called in the order in which they were set.

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