Map demoΒΆ

../_images/MapDemo.png
import random
import sys
import time
import numpy as np

from qwt.qt.QtGui import QApplication, QPen, QBrush, QMainWindow, QToolBar
from qwt.qt.QtCore import QSize
from qwt.qt.QtCore import 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, np.float)
        self.ys = np.zeros(self.count, np.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 resizeEvent(self, event):
        self.plot.resize(event.size())
        self.plot.move(0, 0)

    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()


def make():
    demo = MapDemo()
    demo.resize(600, 600)
    demo.show()
    return demo


if __name__ == '__main__':
    app = QApplication(sys.argv)
    demo = make()
    sys.exit(app.exec_())