Initializing help system before first use

problem.chgColType

Purpose
Used to change the type of a specified set of columns in the matrix.
Topic areas
Problem Modification, MIP Entities
Synopsis
problem.chgColType(colind, coltype)
Arguments
colind 
Integer array containing the indices of the columns.
coltype 
Character array giving the new column types:
C 
indicates a continuous column;
B 
indicates a binary column;
I 
indicates an integer column.
S 
indicates a semi–continuous column. The semi–continuous lower bound will be set to 1.0.
R 
indicates a semi–integer column. The semi–integer lower bound will be set to 1.0.
P 
indicates a partial integer column. The partial integer limit will be set to 1.0.
Further information
1. The column types can only be changed before the tree search is started.
2. Calling problem.chgColType to change any variable into a binary variable causes the bounds previously defined for the variable to be deleted and replaced by bounds of 0 and 1.
3. Calling problem.chgColType to change a continuous variable into an integer variable cause its lower bound to be rounded up to the nearest integer value and its upper bound to be rounded down to the nearest integer value.
4. After changing the type of a column to semi-continuous, semi-integer or partial integer, call problem.chgGlbLimit to set the limit value.
5. This function cannot be called while the current problem is being solved or when it is in an interrupted state. Use problem.postSolve to restore the problem to a non-solving state.
6. For performance reasons, avoid turning MIP entities into continuous columns by calling problem.chgColType many times in the presence of SOS constraints. If an application has this requirement, it is recommended to first collect all such columns beforehand and then change their type in a single call to this function.
7. Argument colind may contain xpress.var objects instead of indices.
Related topics
problem.addCols, problem.chgRowType, problem.delCols, problem.getColType, problem.chgGlbLimit.

Parent Topic Methods of the class problem

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