我在 Python 中使用多处理来计算 ecoinvent v3.2 数据库中所有功能单元的 LCA 结果以进行多次迭代时遇到问题。
代码如下:
for worker_id in range(CPUS):
# Create child processes that can work apart from parent process
child = mp.Process(target=worker_process, args=(projects.current, output_dir, worker_id, activities, ITERATIONS, status))
workers.append(child)
child.start()
print(workers)
while any(i.is_alive() for i in workers):
time.sleep(0.1)
while not status.empty():
# Flush queue of progress reports
worker, completed = status.get()
progress[worker] = completed
progbar.update(sum(progress.values()))
progbar.finish()
定义worker_process
函数如下:
def worker_process(project, output_dir, worker_id, activities, iterations, progress_queue):
# Project is string; project name in Brightway2
# output_dir is a string
# worker_id is an integer
# activities is a list of dictionaries
# iterations is an integer
# progress_queue is a Queue where we can report progress to parent process
projects.set_current(project, writable=False)
lca = DirectSolvingPVLCA(activities[0])
lca.load_data()
samples = np.empty((iterations, lca.params.shape[0]))
supply_arrays = np.empty((iterations, len(activities), len(lca.product_dict)))
for index in range(iterations):
lca.rebuild_all()
samples[index, :] = lca.sample
lca.decompose_technosphere()
for act_index, fu in enumerate(activities):
lca.build_demand_array(fu)
supply_arrays[index, act_index, :] = lca.solve_linear_system()
progress_queue.put((worker_id, index))
观察到的问题是:
对于两个以上的工人,除了两个之外,所有工人都立即死于 a
MemoryError
(见下文)。对于两个幸存的工人来说,代码似乎适用于 10、100 或 5000 个功能单元,但当我们要求所有 FU 时,它会崩溃并运行到相同的
MemoryError
.
MemoryError
每个X进程都会发生这种情况:
Process Process-X:
Traceback (most recent call last):
File "C:\bw2-python\envs\bw2\lib\multiprocessing\process.py", line 254, in_bootstrap
self.run()
File "C:\bw2-python\envs\bw2\lib\multiprocessing\process.py", line 93, in run
self._target(*self._args, **self._kwargs)
File "C:\test\Do all the calculations.py", line 49, in worker_process
supply_arrays = np.empty((iterations, len(activities), len(lca.product_dict)))
MemoryError
我的问题是:
为什么会出现这种情况?
如何解决这个问题?