从 IPOPT Display Pyomo 获取价值

Question

这是我的 Rosenbrock 具体模型代码。

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)

solver.solve 行通过 tee=True 时会打印出各种漂亮信息的漂亮显示。我想从 prinout 访问该信息并搜索了 Pyomo 和 IPOPT 文档，但似乎无法理解如何访问打印到屏幕上的值。我还包含了一个简短的打印输出示例，我想保存每个运行的值，以便我可以迭代并收集整个范围内的统计信息。

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值，但我在搜索文档时发现没有可行的接口来访问它们，任何向导都知道如何做到这一点？谢谢。

Answer 1

查看贡献给 Pyomo 的 Ipopt 求解器包装器。它本质上是 Ipopt 输出日志的解析器，您应该能够 generalize/expand 它来收集当前未收集的任何值。

https://github.com/Pyomo/pyomo/blob/master/pyomo/contrib/parmest/ipopt_solver_wrapper.py

从 IPOPT Display Pyomo 获取价值

Getting Values from IPOPT Display Pyomo

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