« Previous « Start » Next »
3 Using the Matlab Interface
The two main routines in the two-layer design of the interface are
shown in Table
1. Page and section references are
given to detailed descriptions on how to use the routines. The user
that is not using TOMLAB can skip reading about the routine
xpressTL. A normal user, not using callbacks, only has to read
about how to call the level 1 interface routine
xpress.
Table 1: The interface routines.
|
| Function |
Description |
Section |
|
| xpress |
The layer one Matlab interface routine, calls the
MEX-file interface xpressmp.dll |
A.1 |
| xpressTL |
The layer two TOMLAB interface routine that calls
xpress.m. Converts the input Prob format before calling
xpress.m and converts back to the output Result structure. |
A.2 |
|
The Xpress
MP control variables, see Section 7 in the Xpress-Optimizer
Reference Manual [
1], are all possible to set from
Matlab. They could be set as input to the interface routine
xpress, but also in the callback routines. The user sets fields in
a structure called
xpcontrol, where the subfield names are the
same as the names of the control variables. The following example
shows how to set the values for one integer variable
XPRS_LPITERLIMIT, one double variable XPRS_OPTIMALITYTOL, and one
character variable valued variable XPRS_OBJNAME. TOMLAB /
Xpress does not use
the prefix XPRS_ in the Matlab structures.
xpcontrol.LPITERLIMIT = 50; % Setting maximal number of global iterations
xpcontrol.OPTIMALITYTOL = 1E-5; % Changing reduced cost tolerance
xpcontrol.OBJNAME = 'ObjF1'; % New name of the objective function
Character valued variables should have ≤ 64 characters.
Note that after the call to the Xpress
MP interface, two global variables
are available, xpControlVariables and xpProblemAttrib.
As subfields they hold the current values of all
Xpress
MP control variables
see Section 7 in [
1],
and all problem attributes,
see Section 8 in [
1].
To list all their fields, just define the variables as global
and give their names
global xpControlVariables xpProblemAttrib
xpControlVariables
xpProblemAttrib
« Previous « Start » Next »
TOMLAB
