Sage Reference Manual: Numerical Optimization - Mirrors

Sage Reference Manual: Numerical Optimization, Release 6.1.1
sage: p.add_variable(binary=True)
1
sage: p.add_variable(lower_bound=-2.0, integer=True)
2
sage: p.add_variable(continuous=True, integer=True)
Traceback (most recent call last):
...
ValueError: ...
sage: p.add_variable(name=’x’,obj=1.0)
3
sage: p.col_name(3)
’x’
sage: p.objective_coefficient(3)
1.0
add_variables(number, lower_bound=0.0, upper_bound=None, binary=False, continuous=False,
integer=False, obj=0.0, names=None)
Add number new variables.
This amounts to adding new columns to the matrix. By default, the variables are both positive, real and
theor coefficient in the objective function is 0.0.
INPUT:
•n - the number of new variables (must be > 0)
•lower_bound - the lower bound of the variable (default: 0)
•upper_bound - the upper bound of the variable (default: None)
•binary - True if the variable is binary (default: False).
•continuous - True if the variable is binary (default: True).
•integer - True if the variable is binary (default: False).
•obj - (optional) coefficient of all variables in the objective function (default: 0.0)
•names - optional list of names (default: None)
OUTPUT: The index of the variable created last.
EXAMPLE:
sage: from sage.numerical.backends.generic_backend import get_solver
sage: p = get_solver(solver = "GLPK")
sage: p.ncols()
0
sage: p.add_variables(5)
4
sage: p.ncols()
5
sage: p.add_variables(2, lower_bound=-2.0, integer=True, names=[’a’,’b’])
6
col_bounds(index)
Return the bounds of a specific variable.
INPUT:
•index (integer) – the variable’s id.
OUTPUT:
64 Chapter 5. LP Solver backends