Map demoΒΆ

../_images/mapdemo.png

import random
import time
import numpy as np

from qtpy.QtWidgets import QMainWindow, QToolBar
from qtpy.QtGui import QPen, QBrush
from qtpy.QtCore import QSize, Qt
from qwt import QwtPlot, QwtSymbol, QwtPlotCurve


def standard_map(x, y, kappa):
    """provide one interate of the inital conditions (x, y)
    for the standard map with parameter kappa."""
    y_new = y - kappa * np.sin(2.0 * np.pi * x)
    x_new = x + y_new
    # bring back to [0,1.0]^2
    if (x_new > 1.0) or (x_new < 0.0):
        x_new = x_new - np.floor(x_new)
    if (y_new > 1.0) or (y_new < 0.0):
        y_new = y_new - np.floor(y_new)
    return x_new, y_new


class MapDemo(QMainWindow):
    def __init__(self, *args):
        QMainWindow.__init__(self, *args)
        self.plot = QwtPlot(self)
        self.plot.setTitle("A Simple Map Demonstration")
        self.plot.setCanvasBackground(Qt.white)
        self.plot.setAxisTitle(QwtPlot.xBottom, "x")
        self.plot.setAxisTitle(QwtPlot.yLeft, "y")
        self.plot.setAxisScale(QwtPlot.xBottom, 0.0, 1.0)
        self.plot.setAxisScale(QwtPlot.yLeft, 0.0, 1.0)
        self.setCentralWidget(self.plot)
        # Initialize map data
        self.count = self.i = 1000
        self.xs = np.zeros(self.count, float)
        self.ys = np.zeros(self.count, float)
        self.kappa = 0.2
        self.curve = QwtPlotCurve("Map")
        self.curve.attach(self.plot)
        self.curve.setSymbol(
            QwtSymbol(QwtSymbol.Ellipse, QBrush(Qt.red), QPen(Qt.blue), QSize(5, 5))
        )
        self.curve.setPen(QPen(Qt.cyan))
        toolBar = QToolBar(self)
        self.addToolBar(toolBar)
        # 1 tick = 1 ms, 10 ticks = 10 ms (Linux clock is 100 Hz)
        self.ticks = 10
        self.tid = self.startTimer(self.ticks)
        self.timer_tic = None
        self.user_tic = None
        self.system_tic = None
        self.plot.replot()

    def setTicks(self, ticks):
        self.i = self.count
        self.ticks = int(ticks)
        self.killTimer(self.tid)
        self.tid = self.startTimer(ticks)

    def moreData(self):
        if self.i == self.count:
            self.i = 0
            self.x = random.random()
            self.y = random.random()
            self.xs[self.i] = self.x
            self.ys[self.i] = self.y
            self.i += 1
            chunks = []
            self.timer_toc = time.time()
            if self.timer_tic:
                chunks.append("wall: %s s." % (self.timer_toc - self.timer_tic))
                print(" ".join(chunks))
            self.timer_tic = self.timer_toc
        else:
            self.x, self.y = standard_map(self.x, self.y, self.kappa)
            self.xs[self.i] = self.x
            self.ys[self.i] = self.y
            self.i += 1

    def timerEvent(self, e):
        self.moreData()
        self.curve.setData(self.xs[: self.i], self.ys[: self.i])
        self.plot.replot()


if __name__ == "__main__":
    from qwt import tests

    tests.test_widget(MapDemo, size=(600, 600))