Aluode/PerceptionLabPortable

1from time import perf_counter2 3import numpy as np4 5import pyqtgraph as pg6 7app = pg.mkQApp()8plt = pg.PlotWidget()9 10app.processEvents()11 12## Putting this at the beginning or end does not have much effect13plt.show()   14 15## The auto-range is recomputed after each item is added,16## so disabling it before plotting helps17plt.enableAutoRange(False, False)18 19def plot():20    start = perf_counter()21    n = 1522    pts = 10023    x = np.linspace(0, 0.8, pts)24    y = np.random.random(size=pts)*0.825    for i in range(n):26        for j in range(n):27            ## calling PlotWidget.plot() generates a PlotDataItem, which 28            ## has a bit more overhead than PlotCurveItem, which is all 29            ## we need here. This overhead adds up quickly and makes a big30            ## difference in speed.31            32            plt.addItem(pg.PlotCurveItem(x=x+i, y=y+j))33            34    dt = perf_counter() - start35    print(f"Create plots took: {dt * 1000:.3f} ms")36 37## Plot and clear 5 times, printing the time it took38for _ in range(5):39    plt.clear()40    plot()41    app.processEvents()42    plt.autoRange()43 44 45 46 47 48def fastPlot():49    ## Different approach:  generate a single item with all data points.50    ## This runs many times faster.51    start = perf_counter()52    n = 1553    pts = 10054    x = np.linspace(0, 0.8, pts)55    y = np.random.random(size=pts)*0.856    shape = (n, n, pts)57    xdata = np.empty(shape)58    xdata[:] = x + np.arange(shape[1]).reshape((1,-1,1))59    ydata = np.empty(shape)60    ydata[:] = y + np.arange(shape[0]).reshape((-1,1,1))61    conn = np.ones(shape, dtype=bool)62    conn[...,-1] = False # make sure plots are disconnected63    item = pg.PlotCurveItem()64    item.setData(xdata.ravel(), ydata.ravel(), connect=conn.ravel())65    plt.addItem(item)66    67    dt = perf_counter() - start68    print("Create plots took: %0.3fms" % (dt*1000))69 70 71## Plot and clear 5 times, printing the time it took72for _ in range(5):73    plt.clear()74    fastPlot()75    app.processEvents()76    plt.autoRange()77 78if __name__ == '__main__':79    pg.exec()80