CPXgetcallbackseqinfo

Usage

Mixed Integer Users Only

The routine CPXgetcallbackseqinfo() accesses information about nodes during the MIP optimization from within user-written callbacks. This routine may be called only when the value of its wherefrom argument is CPX_CALLBACK_MIP_NODE. The information accessed from this routine can also be accessed with the routine CPXgetcallbacknodeinfo(). Nodes are not stored by sequence number but by node number, so using the routine CPXgetcallbackseqinfo() can be much more time-consuming than using the routine CPXgetcallbacknodeinfo(). A typical use of this routine would be to obtain the node number of a node for which the sequence number is known and then use that node number to select the node with the node callback.

This routine cannot retrieve information about nodes that have been moved to node files. For more information about node files, see the CPLEX User's Manual. If the argument seqnum refers to a node in a node file, CPXgetcallbacknodeinfo() returns the value CPXERR_NODE_ON_DISK.

The routine returns a zero on success, and a nonzero if an error occurs.

The return value CPXERR_NODE_ON_DISK indicates an attempt to access a node currently located in a node file on disk.

int CPXgetcallbackseqinfo (CPXCENVptr env, void *cbdata, int wherefrom, int seqnum, int whichinfo, void *result_p);

Arguments

The pointer to the ILOG CPLEX environment, as returned by one of the CPXopenCPLEX routines.

The pointer passed to the user-written callback. This parameter must be the value of cbdata passed to the user-written callback.

An integer value indicating where the user-written callback was called from. This parameter must be the value of wherefrom passed to the user-written callback.

The sequence number of the node for which information is requested.

An integer indicating which information is requested. For a summary of possible values, refer to the table Information Requested for a User-Written Node Callback in the description of CPXgetcallbacknodeinfo().

A generic pointer to a variable of type double or int, representing the value returned by whichinfo. The column C Type in the table Information Requested for a User-Written Node Callback indicates the type of various values returned by whichinfo.