Stop Scipy Minimize After Set Time

I use minimize from the Scipy module on Python 3.4, specifically: resultats=minimize(margin_rate, iniprices, method='SLSQP', jac=margin_rate_deriv, bounds=pricebounds, options={'di

Solution 1:

You can use the callback argument to raise a warning or exception if the execution time exceeds some threshold:

import numpy as np
from scipy.optimize import minimize, rosen
import time
import warnings

classTookTooLong(Warning):
    passclassMinimizeStopper(object):
    def__init__(self, max_sec=60):
        self.max_sec = max_sec
        self.start = time.time()
    def__call__(self, xk=None):
        elapsed = time.time() - self.start
        if elapsed > self.max_sec:
            warnings.warn("Terminating optimization: time limit reached",
                          TookTooLong)
        else:
            # you might want to report other stuff hereprint("Elapsed: %.3f sec" % elapsed)

# example usage
x0 = [1.3, 0.7, 0.8, 1.9, 1.2]
res = minimize(rosen, x0, method='Nelder-Mead', callback=MinimizeStopper(1E-3))

Solution 2:

No. What you can do is start the optimizer in a separate process, keep track of how long it has been running and terminate it if necessary:

from multiprocessing import Process, Queue
import time
import random
from __future__ import print_function

deff(param, queue):
    #do the minimization and add result to queue#res = minimize(param)#queue.put(res)#to make this a working example I'll just sleep a #a random amount of time
    sleep_amount = random.randint(1, 10)
    time.sleep(sleep_amount)
    res = param*sleep_amount
    queue.put(res)

q = Queue()
p = Process(target=f, args=(2.2, q))
max_time = 3
t0 = time.time()

p.start()
while time.time() - t0 < max_time:
    p.join(timeout=1)
    ifnot p.is_alive():
        breakif p.is_alive():
    #process didn't finish in time so we terminate it
    p.terminate()
    result = Noneelse:
    result = q.get()
print(result)