maartenbreddels

import threading
from IPython.display import display
import ipywidgets as widgets
import time
def get_ioloop():
    import IPython, zmq
    ipython = IPython.get_ipython()
    if ipython and hasattr(ipython, 'kernel'):
        return zmq.eventloop.ioloop.IOLoop.instance()
ioloop = get_ioloop()

maartenbreddels

__author__ = 'breddels'
"""
Demonstrates combining Qt and tornado, both which want to have their own event loop.
The solution is to run tornado in a thread, the issue is that callbacks will then also be executed in this thread, and Qt doesn't like that.
To fix this, I show how to use execute the callback in the main thread, using a Qt signal/event in combination with Promises.

The output of the program is:
fetch page, we are in thread <_MainThread(MainThread, started 47200787479520)>
response is 191548 bytes, we are in thread <Thread(Thread-1, started daemon 47201018689280)>
the other thread should fulfil the result to this promise, we are in thread <Thread(Thread-1, started daemon 47201018689280)>

maartenbreddels

#include <Python.h>
#include <math.h>
#include <stdexcept>
#include <cstdio>
#include <numpy/arrayobject.h>


template<typename T>
void object_to_numpy1d_nocopy(T* &ptr, PyObject* obj, long long  &count, int& stride=stride_default, int type=NPY_DOUBLE) {
		if(obj == NULL)