odebook.py 文件源码

def plottrajectories(fs, x0, t=np.linspace(1,400,10000), **kw):
    """
    plots trajectory of the solution

    f  -- must accept an array of X and t=0, and return a 2D array of \dot y and \dot x
    x0 -- vector

    Example
    =======

    plottrajectories(lambda X,t=0:array([ X[0] -   X[0]*X[1] ,
                   -X[1] + X[0]*X[1] ]), [ 5,5], color='red')
    """
    x0 = np.array(x0)
    #f = lambda X,t=0: array(fs(X[0],X[1]))
    #fa = lambda X,t=0:array(fs(X[0],X[1]))
    X = integrate.odeint( fs, x0, t)
    plt.plot(X[:,0], X[:,1], **kw)