CPXcopybase

The routine CPXcopybase is used to copy a basis into a CPLEX problem object. It is not necessary to copy a basis prior to optimizing an LP problem, but a good initial basis can increase the speed of optimization significantly. A basis does not need to be primal or dual feasible to be used by the optimizer.

Note

The basis is ignored by the optimizer if CPX_PARAM_ADVIND is set to CPX_OFF.

Table 1: Values of basis status for columns in cstat[j]
`CPX_AT_LOWER`	`0`	variable at lower bound
`CPX_BASIC`	`1`	variable is basic
`CPX_AT_UPPER`	`2`	variable at upper bound
`CPX_FREE_SUPER`	`3`	variable free and nonbasic

Table 2: Values of basis status for rows other than ranged rows in rstat[j]
`CPX_AT_LOWER`	`0`	associated slack/surplus/artificial variable nonbasic at value 0.0
`CPX_BASIC`	`1`	associated slack/surplus/artificial variable basic

Table 3: Values of basis status for ranged rows in rstat[j]
`CPX_AT_LOWER`	`0`	associated slack/surplus/artificial variable nonbasic at its lower bound
`CPX_BASIC`	`1`	associated slack/surplus/artificial variable basic
`CPX_AT_UPPER`	`2`	associated slack/surplus/artificial variable nonbasic at its upper bound

Example

 status = CPXcopybase (env, lp, cstat, rstat);

CPXcopybase

Parameters:

Returns:

env	A pointer to the CPLEX environment as returned by `CPXopenCPLEX`.
lp	A pointer to a CPLEX problem object as returned by `CPXcreateprob`.
cstat	An array containing the basis status of the columns in the constraint matrix. The length of the array is equal to the number of columns in the problem object. Possible values of the basis status of columns appear in Table 1.
rstat	An array containing the basis status of the slack/surplus/artificial variable associated with each row in the constraint matrix. The array's length is equal to the number of rows in the CPLEX problem object. For rows other than ranged rows, the array element `rstat[i]` has the meaning in Table 2. For ranged rows, the array element `rstat[i]` has the meaning in Table 3.