49 lines
1.4 KiB
Python
49 lines
1.4 KiB
Python
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"""valley2.py
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~~~~~~~~~~~~~
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Plots a function of two variables to minimize. The function is a
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fairly generic valley function.
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Note that this is a duplicate of valley.py, but omits labels on the
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axis. It's bad practice to duplicate in this way, but I had
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considerable trouble getting matplotlib to update a graph in the way I
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needed (adding or removing labels), so finally fell back on this as a
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kludge solution.
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"""
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#### Libraries
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# Third party libraries
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from matplotlib.ticker import LinearLocator
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# Note that axes3d is not explicitly used in the code, but is needed
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# to register the 3d plot type correctly
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from mpl_toolkits.mplot3d import axes3d
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import matplotlib.pyplot as plt
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import numpy
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fig = plt.figure()
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ax = fig.gca(projection='3d')
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X = numpy.arange(-1, 1, 0.1)
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Y = numpy.arange(-1, 1, 0.1)
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X, Y = numpy.meshgrid(X, Y)
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Z = X**2 + Y**2
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colortuple = ('w', 'b')
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colors = numpy.empty(X.shape, dtype=str)
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for x in xrange(len(X)):
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for y in xrange(len(Y)):
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colors[x, y] = colortuple[(x + y) % 2]
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surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, facecolors=colors,
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linewidth=0)
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ax.set_xlim3d(-1, 1)
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ax.set_ylim3d(-1, 1)
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ax.set_zlim3d(0, 2)
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ax.w_xaxis.set_major_locator(LinearLocator(3))
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ax.w_yaxis.set_major_locator(LinearLocator(3))
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ax.w_zaxis.set_major_locator(LinearLocator(3))
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ax.text(1.79, 0, 1.62, "$C$", fontsize=20)
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plt.show()
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