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Improve CSTR model #56

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Improve CSTR model #56

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23 changes: 7 additions & 16 deletions gdplib/cstr/gdp_reactor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -90,12 +90,6 @@ def F0_Def(m, i):
# Unreacted feed in reactor n
m.YF = pyo.BooleanVar(m.N, doc="Unreacted feed in reactor n")

# Existence of recycle flow in unit n
m.YR = pyo.BooleanVar(m.N, doc="Existence of recycle flow in unit n")

# Unit operation in n (True if unit n is a CSTR, False if unit n is a bypass)
m.YP = pyo.BooleanVar(m.N, doc="Unit operation in n")

# REAL VARIABLES

# Network Variables
Expand Down Expand Up @@ -784,11 +778,6 @@ def YR_is_recycle_or_not(m, n):
"""
return [m.YR_is_recycle[n], m.YR_is_not_recycle[n]]

# Associate Boolean variables with with disjunctions
for n in m.N:
m.YP[n].associate_binary_var(m.YP_is_cstr[n].indicator_var)
m.YR[n].associate_binary_var(m.YR_is_recycle[n].indicator_var)

# Logic Constraints
# Unit must be a CSTR to include a recycle

Expand All @@ -809,7 +798,7 @@ def cstr_if_recycle_rule(m, n):
Pyomo.LogicalConstraint
Logical constraint for the unit to be a CSTR to include a recycle.
"""
return m.YR[n].implies(m.YP[n])
return m.YR_is_recycle[n].indicator_var.implies(m.YP_is_cstr[n].indicator_var)

m.cstr_if_recycle = pyo.LogicalConstraint(
m.N, rule=cstr_if_recycle_rule, doc="Unit must be a CSTR to include a recycle"
Expand Down Expand Up @@ -853,7 +842,9 @@ def one_recycle_rule(m):
Pyomo.LogicalConstraint
Logical constraint for the existence of only one recycle stream.
"""
return pyo.exactly(1, m.YR)
return pyo.exactly(
1, [m.YR_is_recycle[n].indicator_var for n in range(1, NT + 1)]
)

m.one_recycle = pyo.LogicalConstraint(
rule=one_recycle_rule, doc="There is only one recycle stream"
Expand Down Expand Up @@ -881,9 +872,9 @@ def unit_in_n_rule(m, n):
Logical constraint for the unit operation in n.
"""
if n == 1:
return m.YP[n].equivalent_to(True)
return m.YP_is_cstr[n].indicator_var.equivalent_to(True)
else:
return m.YP[n].equivalent_to(
return m.YP_is_cstr[n].indicator_var.equivalent_to(
pyo.lor(pyo.land(~m.YF[n2] for n2 in range(1, n)), m.YF[n])
)

Expand Down Expand Up @@ -915,7 +906,7 @@ def obj_rule(m):


if __name__ == "__main__":
m = build_model()
m = build_model(NT=5)
pyo.TransformationFactory("core.logical_to_linear").apply_to(m)
pyo.TransformationFactory("gdp.bigm").apply_to(m)
pyo.SolverFactory("gams").solve(
Expand Down
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