Initializing help system before first use

branchobj.addrows

Purpose
Adds new constraints to a branch of a user branching object.
Synopsis
branchobj.addrows(branch, rowtype, rhs, start, colind, rowcoef)
Arguments
branch 
The number of the branch to add the new constraints for. This branch must already have been created using branchobj.addbranches. Branches are indexed starting from zero.
rowtype 
Character array indicating the type of constraints to add:
L 
Less than type.
G 
Greater than type.
E 
Equality type.
rhs 
Array containing the right-hand side values.
start 
Array containing the offsets in the colind and rowcoef arrays of the start of the nonzero coefficients for each new constraint. The array must contain one more element than the number of rows to add, with the last element being the total number of coefficients across all rows.
colind 
Array containing the columns for the nonzero coefficients.
rowcoef 
Array containing the nonzero coefficient values.
Example
The following function will create a branching object that branches on constraints x1 + x2 ≥ 1 or x1 + x2 ≤ 0, where x1 and x2 are instances of xpress.var: 
def CreateConstraintBranch(prob, x1, x2):

    # Create the new object with two empty branches.
    bo = xpress.branchobj(prob, isoriginal=True)
    bo.addbranches(2)

    # Add the constraints to the branching object
    # x1 + x2 >= 1
    # x1 + x2 <= 0
    bo.addrows(0, ['G'], [1.0], [0], [x1, x2], [1.0, 1.0])
    bo.addrows(1, ['L'], [0.0], [0], [x1, x2], [1.0, 1.0])

    # Set a low priority value so our branch object is picked up
    # before the default branch candidates.
    bo.setpriority(100)

    return bo

Parent Topic Xpress branch object methods

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