从IPOPT显示器Pyomo中获取值

Question

这是我的罗森布罗克模型的代码。

from pyomo.environ import *
from pyomo.opt import SolverFactory
import numpy as np
import math
import statistics
import time

m = ConcreteModel()

m.x = Var()
m.y = Var()
m.z = Var()

def rosenbrock(model):
    return (1.0-m.x)2 + 100.0*(m.y - m.x2)2 + (1.0-m.y)2 + 100.0*(m.z - m.y2)2

m.obj = Objective(rule=rosenbrock, sense=minimize)

dist = 0.0
xval = yval = zval = error = times = []
for i in range(50):
    m.x = np.random.uniform(low=-5.0, high=5.0)
    m.y = np.random.uniform(low=-5.0, high=5.0)
    m.z = np.random.uniform(low=-5.0, high=5.0)
    solver = SolverFactory('ipopt')
    t1 = time.time()
    results = solver.solve(m, tee=True)

当传递solver.solve行时，tee=True会打印出各种精美信息的漂亮显示。我希望从打印输出中访问这些信息，并且已经浏览了Pyomo和IPOPT文档，并且似乎无法理解如何访问打印到屏幕上的值。我还提供了一个打印输出的简短示例，我希望保存每次运行中的值，以便可以迭代和收集整个范围的统计信息。

Number of nonzeros in equality constraint Jacobian...:        0
Number of nonzeros in inequality constraint Jacobian.:        0
Number of nonzeros in Lagrangian Hessian.............:        5

Total number of variables............................:        3
                     variables with only lower bounds:        0
                variables with lower and upper bounds:        0
                     variables with only upper bounds:        0
Total number of equality constraints.................:        0
Total number of inequality constraints...............:        0
        inequality constraints with only lower bounds:        0
   inequality constraints with lower and upper bounds:        0
        inequality constraints with only upper bounds:        0

*省略*

Number of objective function evaluations             = 45
Number of objective gradient evaluations             = 23
Number of equality constraint evaluations            = 0
Number of inequality constraint evaluations          = 0
Number of equality constraint Jacobian evaluations   = 0
Number of inequality constraint Jacobian evaluations = 0
Number of Lagrangian Hessian evaluations             = 22
Total CPU secs in IPOPT (w/o function evaluations)   =      0.020
Total CPU secs in NLP function evaluations           =      0.000

我需要这些值中的一些，但我发现没有任何可行的接口可以通过我对文档的搜索来访问它们，任何向导都知道如何做到这一点？谢谢。

Answer 1

参见这个Ipopt解决器包装，它是对Pyomo的贡献。它本质上是Ipopt输出日志的解析器，您应该能够对它进行泛化/扩展，以收集当前未收集的任何值。

wrapper.py