def test_objective(self):
lp_str = """
Maximize
obj: x1 + 2 x2 + 3 x3 + x4 + 10
Subject To
c1: - x1 + x2 + x3 + 10 x4 <= 20
c2: x1 - 3 x2 + x3 <= 30
c3: x2 - 3.5 x4 = 0
Bounds
0 <= x1 <= 40
2 <= x4 <= 3
General
x4
Binary
x2
End
"""
lp_problem = LpReader.read(io.StringIO(lp_str))
assert lp_problem.lp_objective.to_lp_terms() == [
'x1', '+ 2 x2', '+ 3 x3', '+ x4', '+ 10.0'
]
assert lp_problem.lp_objective.name == 'obj'
assert lp_problem.lp_objective.const == 10
def test_constraints(self):
lp_str = """
Maximize
obj: x1 + 2 x2 + 3 x3 + x4 + 10
Subject To
c1: - x1 + x2 + x3 + 10 x4 <= 20
c2: x1 - 3 x2 + x3 <= 30
c3: x2 - 3.5 x4 = 0
Bounds
0 <= x1 <= 40
2 <= x4 <= 3
General
x4
Binary
x2
End
"""
lp_problem = LpReader.read(io.StringIO(lp_str))
assert lp_problem.lp_constraints['c1'].to_lp_terms() == [
'- x1', '+ x2', '+ x3', '+ 10 x4', '<=', '20.0'
]
assert lp_problem.lp_constraints['c2'].to_lp_terms() == [
'x1', '- 3 x2', '+ x3', '<=', '30.0'
]
assert lp_problem.lp_constraints['c3'].to_lp_terms() == [
'x2', '- 3.5 x4', '=', '0.0'
]
def test_constraints_exceptions(self):
lp_str = """
Maximize
obj: x1 + 2 x2 + 3 x3 + x4 + 10
Subject To
c1: - x1 + x2 + x3 + 10 x4
c2: x1 - 3 x2 + x3 <= 30
c3: x2 - 3.5 x4 = 0
Bounds
0 <= x1 <= 40
2 <= x4 <= 3
General
x4
Binary
x2
End
"""
with pytest.raises(Exception) as e:
lp_problem = LpReader.read(io.StringIO(lp_str))
assert str(
e.value
) == "constraint c1: - x1 + x2 + x3 + 10 x4\n c2: x1 - 3 x2 + x3 <= 30 doesn't appear to be valid"
def test_variable_types(self):
lp_str = """
Maximize
obj: x1 + 2 x2 + 3 x3 + x4 + 10
Subject To
c1: - x1 + x2 + x3 + 10 x4 <= 20
c2: x1 - 3 x2 + x3 <= 30
c3: x2 - 3.5 x4 = 0
Bounds
0 <= x1 <= 40
2 <= x4 <= 3
x3 <= 3
General
x4
Binary
x2
End
"""
lp_problem = LpReader.read(io.StringIO(lp_str))
assert lp_problem.lp_variables['x1'].low_bound == 0
assert lp_problem.lp_variables['x1'].up_bound == 40
assert lp_problem.lp_variables['x1'].var_type == VarType.Continuous
assert lp_problem.lp_variables['x2'].low_bound == 0
assert lp_problem.lp_variables['x2'].up_bound == 1
assert lp_problem.lp_variables['x2'].var_type == VarType.Binary
assert lp_problem.lp_variables['x3'].low_bound == 0
assert lp_problem.lp_variables['x3'].up_bound == 3.0
assert lp_problem.lp_variables['x3'].var_type == VarType.Continuous
assert lp_problem.lp_variables['x4'].low_bound == 2
assert lp_problem.lp_variables['x4'].up_bound == 3
assert lp_problem.lp_variables['x4'].var_type == VarType.Integer