Python 能量系统的 GEKKO MINLP 优化:如何构建二维数组的中间体

Python GEKKO MINLP optimization of energy system: How to build intermediates that are 2D arrays

我目前正在 Python GEKKO 中实施 MINLP 优化问题,以确定三联产能源系统的最佳运行策略。由于我将不同代表性日期的所有时段的能源需求视为输入数据,因此基本上我所有的决策变量、中间值等都是二维数组。 我怀疑二维中间体的声明是我的问题。现在我使用列表理解来声明 2D 中间体,但似乎 python 不能使用这些中间体。此外,错误 This steady-state IMODE only allows scalar values. 发生。

每当我像这样使用 GEKKO m.Array 函数时: e_GT = m.Array(m.Intermediate(E_GT[z][p]/E_max_GT) for z in range(Z) for p in range(P), (Z,P)) 它说,无法调用 GEKKO 对象 m.Intermediate。

如果有人能给我提示,我将不胜感激。

完整代码如下:

"""
Created on Fri Nov 22 10:18:33 2019

@author: julia
"""
# __Get GEKKO & numpy___
from gekko import GEKKO
import numpy as np

# ___Initialize model___
m = GEKKO()

# ___Global options_____
m.options.SOLVER = 1                                                            # APOPT is MINLP Solver

# ______Constants_______                                                       
i = m.Const(value=0.05)                                                        
n = m.Const(value=10)                                                          
C_GT = m.Const(value=100000)                                                                         
C_RB = m.Const(value=10000)                                                            
C_HB = m.Const(value=10000)                                                            
C_RS = m.Const(value=10000)                                                           
C_RE = m.Const(value=10000)                                                          
Z = 12                                                                         
P = 24                                                                       
E_min_GT = m.Const(value=1000)                                                 
E_max_GT = m.Const(value=50000)                                                
F_max_GT = m.Const(value=100000)                                               
Q_max_GT = m.Const(value=100000)                                               
a = m.Const(value=1)                                                           
b = m.Const(value=1)                                                           
c = m.Const(value=1)                                                            
d = m.Const(value=1)                                                           
eta_RB = m.Const(value=0.01)                                                   
eta_HB = m.Const(value=0.01)                                                   
eta_RS = m.Const(value=0.01)                                                   
eta_RE = m.Const(value=0.01)                                                    
alpha = m.Const(value=0.01)                                                     

# ______Parameters______
T_z = m.Param([31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31])                
C_p_Gas = m.Param(np.ones([P]))  
C_p_Elec = m.Param(np.ones([P]))
E_d = np.ones([Z,P])
H_d = np.ones([Z,P])
K_d = np.ones([Z,P])

# _______Variables______
E_purch = m.Array(m.Var, (Z,P), lb=0)                                           
E_GT = m.Array(m.Var, (Z,P), lb=0)                                              
F_GT = m.Array(m.Var, (Z,P), lb=0)                                              
Q_GT = m.Array(m.Var, (Z,P), lb=0)                                              
Q_GT_RB = m.Array(m.Var, (Z,P), lb=0)                                          
Q_disp = m.Array(m.Var, (Z,P), lb=0)                                           
Q_HB = m.Array(m.Var, (Z,P), lb=0)                                              
K_RS = m.Array(m.Var, (Z,P), lb=0)                                              
K_RE = m.Array(m.Var, (Z,P), lb=0)                                              
delta_GT = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_RB = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_HB = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_RS = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                     
delta_RE = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      

# ____Intermediates_____      
R = m.Intermediate((i*(1+i)**n)/((1+i)**n-1))                                   
e_min_GT = m.Intermediate(E_min_GT/E_max_GT)                                    
e_GT = [m.Intermediate(E_GT[z][p]/E_max_GT) for z in range(Z) for p in range(P)]
f_GT = [m.Intermediate(F_GT[z][p]/F_max_GT) for z in range(Z) for p in range(P)]      
q_GT = [m.Intermediate(Q_GT[z][p]/Q_max_GT) for z in range(Z) for p in range(P)]                                  
Q_RB = [m.Intermediate(eta_RB*Q_GT_RB[z][p]*delta_RB[z][p]) for z in range(Z) for p in range(P)]   
F_HB = [m.Intermediate(eta_HB*Q_HB[z][p]*delta_HB[z][p]) for z in range(Z) for p in range(P)]       
Q_RS = [m.Intermediate(eta_RS*K_RS[z][p]*delta_RS[z][p]) for z in range(Z) for p in range(P)]       
E_RE = [m.Intermediate(eta_RE*K_RE[z][p]*delta_RE[z][p])  for z in range(Z) for p in range(P)]      
F_Gas = [m.Intermediate(F_GT[z][p] + eta_HB*Q_HB[z][p]*delta_HB[z][p]) for z in range(Z) for p in range(P)]                 
Cc = m.Intermediate(R*(C_GT + C_RB + C_HB + C_RS + C_RE))                                           
Cr_z = m.Intermediate((sum(C_p_Gas[p]*F_Gas[z][p] + C_p_Elec[p]*E_purch[z][p]) for p in range(P)) for z in range(Z)) 
Cr = m.Intermediate(sum(Cr_z[z]*T_z[z]) for z in range(Z))                                           

# ______Equations_______                                                
m.Equation(e_min_GT[z][p]*delta_GT[z][p] <= e_GT[z][p] for z in range(Z) for p in range(P))         
m.Equation(e_GT[z][p] <= 1*delta_GT[z][p] for z in range(Z) for p in range(P))                      
m.Equation(f_GT [z][p]== a*delta_GT[z][p] + b*e_GT[z][p] for z in range(Z) for p in range(P))       
m.Equation(q_GT [z][p]== c*delta_GT[z][p] + d*e_GT[z][p] for z in range(Z) for p in range(P))        
m.Equation(E_purch[z][p] + E_GT[z][p] == E_RE[z][p] + E_d[z][p] for z in range(Z) for p in range(P)) 
m.Equation(Q_GT[z][p] == Q_disp[z][p] + Q_GT_RB[z][p] for z in range(Z) for p in range(P))          
m.Equation(Q_RB[z][p] + Q_HB[z][p] == Q_RS[z][p] + H_d[z][p] for z in range(Z) for p in range(P))    
m.Equation(K_RS[z][p] + K_RE[z][p] == K_d[z][p] for z in range(Z) for p in range(P))                 
m.Equation(Q_disp[z][p] <= alpha*Q_GT[z][p] for z in range(Z) for p in range(P))                     

# ______Objective_______
m.Obj(Cc + Cr)

#_____Solve Problem_____
m.solve()

为了诊断问题,我在解决命令之前添加了打开 运行 文件夹的调用。

#_____Solve Problem_____
m.open_folder()
m.solve()

我用文本编辑器打开了 gk_model0.apm 模型文件来查看模型的文本版本。最下面显示最后两个中间体和9个方程有问题

    i2327=<generator object <genexpr> at 0x0E51BC30>
    i2328=<generator object <genexpr> at 0x0E51BC30>
End Intermediates
Equations
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    <generator object <genexpr> at 0x0E51BC30>
    minimize (i2326+i2328)
End Equations

End Model

ParamVar.value 属性 是列表或 numpy 数组而不是标量值时,就会发生这种情况。

# ______Parameters______
#T_z = m.Param([31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]) 
T_z = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

还有一些其他问题,例如

  • e_min_GT 在第一个等式中被引用为列表的元素而不是标量值
  • 中间列表理解中缺少方括号,使列表成为二维的,例如 [[2 for p in range(P)] for z in range(Z)]
  • 尺寸不匹配 for z in range(Z)] for p in range(P)] 而不是 for p in range(P)] for z in range(Z)]
  • 为了提高效率,请使用 m.sum 而不是 sum

我还进行了其他一些更改。差分程序应该显示它们。

"""
Created on Fri Nov 22 10:18:33 2019

@author: julia
"""
# __Get GEKKO & numpy___
from gekko import GEKKO
import numpy as np

# ___Initialize model___
m = GEKKO()

# ___Global options_____
m.options.SOLVER = 1   # APOPT is MINLP Solver

# ______Constants_______                                                       
i = m.Const(value=0.05)                                                        
n = m.Const(value=10)                                                          
C_GT = m.Const(value=100000)                                                                         
C_RB = m.Const(value=10000)                                                            
C_HB = m.Const(value=10000)                                                            
C_RS = m.Const(value=10000)                                                           
C_RE = m.Const(value=10000)                                                          
Z = 12                                                                         
P = 24                                                                       
E_min_GT = m.Const(value=1000)                                                 
E_max_GT = m.Const(value=50000)                                                
F_max_GT = m.Const(value=100000)                                               
Q_max_GT = m.Const(value=100000)                                               
a = m.Const(value=1)                                                           
b = m.Const(value=1)                                                           
c = m.Const(value=1)                                                            
d = m.Const(value=1)                                                           
eta_RB = m.Const(value=0.01)                                                   
eta_HB = m.Const(value=0.01)                                                   
eta_RS = m.Const(value=0.01)                                                   
eta_RE = m.Const(value=0.01)                                                    
alpha = m.Const(value=0.01)                                                     

# ______Parameters______
T_z = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
C_p_Gas = np.ones(P)  
C_p_Elec = np.ones(P)
E_d = np.ones([Z,P])
H_d = np.ones([Z,P])
K_d = np.ones([Z,P])              

# _______Variables______
E_purch = m.Array(m.Var, (Z,P), lb=0)                                           
E_GT = m.Array(m.Var, (Z,P), lb=0)                                              
F_GT = m.Array(m.Var, (Z,P), lb=0)                                              
Q_GT = m.Array(m.Var, (Z,P), lb=0)                                              
Q_GT_RB = m.Array(m.Var, (Z,P), lb=0)                                          
Q_disp = m.Array(m.Var, (Z,P), lb=0)                                           
Q_HB = m.Array(m.Var, (Z,P), lb=0)                                              
K_RS = m.Array(m.Var, (Z,P), lb=0)                                              
K_RE = m.Array(m.Var, (Z,P), lb=0)                                              
delta_GT = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_RB = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_HB = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      
delta_RS = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                     
delta_RE = m.Array(m.Var, (Z,P), lb=0, ub=1, integer=True)                      

# ____Intermediates_____      
R = m.Intermediate((i*(1+i)**n)/((1+i)**n-1))                                   
e_min_GT = m.Intermediate(E_min_GT/E_max_GT)                                    
e_GT = [[m.Intermediate(E_GT[z][p]/E_max_GT) for p in range(P)] for z in range(Z)]
f_GT = [[m.Intermediate(F_GT[z][p]/F_max_GT) for p in range(P)] for z in range(Z)]      
q_GT = [[m.Intermediate(Q_GT[z][p]/Q_max_GT) for p in range(P)] for z in range(Z)]                                  
Q_RB = [[m.Intermediate(eta_RB*Q_GT_RB[z][p]*delta_RB[z][p]) for p in range(P)] for z in range(Z)]   
F_HB = [[m.Intermediate(eta_HB*Q_HB[z][p]*delta_HB[z][p]) for p in range(P)] for z in range(Z)]       
Q_RS = [[m.Intermediate(eta_RS*K_RS[z][p]*delta_RS[z][p]) for p in range(P)] for z in range(Z)]       
E_RE = [[m.Intermediate(eta_RE*K_RE[z][p]*delta_RE[z][p])  for p in range(P)] for z in range(Z)]      
F_Gas = [[m.Intermediate(F_GT[z][p] + eta_HB*Q_HB[z][p]*delta_HB[z][p]) for p in range(P)] for z in range(Z)]                 
Cc = m.Intermediate(R*(C_GT + C_RB + C_HB + C_RS + C_RE))                                           
Cr_z = [m.Intermediate(m.sum([C_p_Gas[p]*F_Gas[z][p] + C_p_Elec[p]*E_purch[z][p] for p in range(P)])) for z in range(Z)]
Cr = m.Intermediate(m.sum([Cr_z[z]*T_z[z] for z in range(Z)]))                                          

# ______Equations_______                                                
m.Equation([e_min_GT*delta_GT[z][p] <= e_GT[z][p] for z in range(Z) for p in range(P)])         
m.Equation([e_GT[z][p] <= 1*delta_GT[z][p] for z in range(Z) for p in range(P)])                      
m.Equation([f_GT [z][p]== a*delta_GT[z][p] + b*e_GT[z][p] for z in range(Z) for p in range(P)])       
m.Equation([q_GT [z][p]== c*delta_GT[z][p] + d*e_GT[z][p] for z in range(Z) for p in range(P)])        
m.Equation([E_purch[z][p] + E_GT[z][p] == E_RE[z][p] + E_d[z][p] for z in range(Z) for p in range(P)]) 
m.Equation([Q_GT[z][p] == Q_disp[z][p] + Q_GT_RB[z][p] for z in range(Z) for p in range(P)])          
m.Equation([Q_RB[z][p] + Q_HB[z][p] == Q_RS[z][p] + H_d[z][p] for z in range(Z) for p in range(P)])    
m.Equation([K_RS[z][p] + K_RE[z][p] == K_d[z][p] for z in range(Z) for p in range(P)])                 
m.Equation([Q_disp[z][p] <= alpha*Q_GT[z][p] for z in range(Z) for p in range(P)])                     

# ______Objective_______
m.Obj(Cc + Cr)

#_____Solve Problem_____
#m.open_folder()
m.solve()

问题求解时间为 1.6 sec

--------- APM Model Size ------------
 Each time step contains
   Objects      :           13
   Constants    :           20
   Variables    :         5209
   Intermediates:         2320
   Connections  :          313
   Equations    :         5213
   Residuals    :         2893

 Number of state variables:           5209
 Number of total equations: -         2905
 Number of slack variables: -          864
 ---------------------------------------
 Degrees of freedom       :           1440

 ----------------------------------------------
 Steady State Optimization with APOPT Solver
 ----------------------------------------------
Iter:     1 I:  0 Tm:      1.53 NLPi:    3 Dpth:    0 Lvs:    0 Obj:  2.69E+04 Gap:  0.00E+00
 Successful solution

 ---------------------------------------------------
 Solver         :  APOPT (v1.0)
 Solution time  :    1.59730000000854      sec
 Objective      :    26890.6404951639     
 Successful solution
 ---------------------------------------------------

二维列表定义需要额外的方括号。这给出了一个 3 行和 4 列的二维列表。

[[p+10*z for p in range(3)] for z in range(4)]
# Result: [[0, 1, 2], [10, 11, 12], [20, 21, 22], [30, 31, 32]]

如果省略内部括号,它是一个长度为 12 的一维列表。

[p+10*z for p in range(3) for z in range(4)]
# Result: [0, 10, 20, 30, 1, 11, 21, 31, 2, 12, 22, 32]

当列表的每个元素都是 Gekko 时它也有效 Intermediate

[[m.Intermediate(p+10*z) for p in range(3)] for z in range(4)]