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Some of The Clp Executable Commands

Convention
The command syntax
     abcd(efgh)
means that the leading characters abcd must appear in the command and that any number of the characters efgh may follow (in that order and are optional). The characters ( and ) do not appear in the command.

Some of the commands below are of limited use or not helpful at all when using e-mail with the Neos interface to Clp . In this case, a comment to this effect is added at the end of the command description.

direction
The syntax for this command is one of the following three choices:
     direction min(imize)
     direction max(imize)
     direction zero
This sets the objective direction for optimization (the default is minimize). You can also set the objective direction using the commands ClpCommand and ClpCommand .

directory
The syntax for this command is
     directory default_directory
This sets the default directory for reading and writing files; i.e., for commands like import . This default directory is initialized to the current working directory; i.e. ./

This command is not useful with the e-mail Neos interface to Clp.

import
The syntax for this command is
     import mps_file_name
This will read the MPS format file specified by mps_file_name. It will use the default directory as specified by the directory command. If mps_file_name is equal to $, the previous value for the file name is used. The file name is initially empty; i.e. it must be set. If you have libgz, Clp can read compressed files by ending mps_file_name with the three characters .gz.

This command is not useful with the e-mail Neos interface to Clp.

maximize
The syntax for this command
     max(imize)
This sets the optimization direction to maximize. (The default optimization direction is to minimize.) You can also use the command direction to set the optimization direction to maximize.

minimize
The syntax for this command is
     min(imize)
This sets the optimization direction to minimize. (the default optimization direction). You can also use the command direction to set the optimization direction to minimize.

primalPivot
The syntax for this command is
     primalP(ivot) selection
This command determines the primal pivot selection method. The possible values for selection are: auto(matic), exa(ct), dant(zig), part(ial), steep(est), change, sprint. The Dantzig method is implemented to show a simple method but its use is deprecated. Exact devex is the method of choice and there are two variants which keep all weights updated but only scan a subset each iteration. Partial switches this on while change initially does dantzig until the factorization becomes denser. This is still a work in progress.

primalSimplex
The syntax for this command is
     primalS(implex)
This command solves the current model using the primal simplex algorithm. The default is to use the exact devex column selection method. The time and iterations may be affected by settings such as presolve, scaling, crash and also by column selection method, infeasibility weight and dual and primal tolerances.

solution
The syntax for this command is
     solu(tion) solu_file_name
print the current solution to the file specified by solu_file_name. This will use the default directory as specified by the previous directory command. If solu_file_name is $, the previous value for the solution file name is used. This solution file name is initialized to stdout (but using this default does not seem to work).

We use  m for the number of rows and  n for the number of columns in the matrix specified by the MPS input file. The solution is output in two parts: The first part is the following values for  i = 0 , \ldots , m-1
     i   row_name_i   row_primal_i   row_dual_value_i
The second part is the following values for  j = 0 , \ldots , n-1
     j   column_name_j   column_primal_j   column_dual_j

If you are using this command with the e-mail Noes interface to Clp, you should use solu_file_name equal to - which instructs Clp to write the solution to standard output.
Input File: ClpCommand.omh