problem.chgcoltype

Purpose

Changes the type of a column in the problem.

Synopsis

problem.chgcoltype(mindex, qctype)

Arguments

mindex

Array containing the columns (i.e. xpress.var objects, indices, or names) whose type is to be changed.

qctype

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 bound will be set to 1.0.

Example

The following changes the type of variable x from binary to integer:

p = xpress.problem()
x = xpress.var(vartype=xp.binary)
p.addVariable(x)
p.chgcoltype([x],['I'])

Further information

1. The column types can only be changed before the global search is started.

2. Calling 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 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.

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problem.chgcoltype

problem.chgcoltype