Bottom Page

• 0 Vote(s) - 0 Average
• 1
• 2
• 3
• 4
• 5
 graphing euler method rondo Unladen Swallow Posts: 1 Threads: 1 Joined: May 2019 Reputation: 0 Likes received: 0 #1 May-02-2019, 08:13 PM My program should Sketch the graph of ?(?) and the approximations ?ℎ(??) with ℎ=1,0.5,0.1 where p(t) is the approximation using Euler's method. I'm new to python and for some reason, I'm not getting three graphs for the three different h values, how can I fix this? ```import numpy as np import matplotlib.pylab as plt def Euler(): K = 12; r = 0.43; Po = 1; N=30; h=[.1,.5,1] #defining dP/dt as a function f(P) f = lambda P: r*P*(1-P/K) P = np.array([]) P = np.append(P,Po) #initializing P with Po for i in range (len(h)): for n in range(N+1):#n=0 as index for P[0], then 1<=n<=N Pn = P[n] + h[i]*f(P[n]) #euler P = np.append(P,Pn) plt. plot ( n, P[n] , 'ro' ) plt. xlabel (' Value of n ”' ) plt. ylabel (" Value of p[n] ”") plt. title (" Approximate Solution with Euler’s Method " ) plt. show ( ) Euler() ``` scidam Posts: 436 Threads: 0 Joined: Mar 2018 Reputation: 61 Likes received: 63 #2 May-03-2019, 01:03 AM I slightly rewrote your code, you can adapt it for your needs. ```import numpy as np import matplotlib.pylab as plt def volterra(P, K=1, r=1): return r * P * (1 - P / K) def euler(fun, Po, h, N, **kwargs): acc = [Po] times = np.cumsum(np.r_[0, np.ones(N) * h]) for _ in range(N): acc.append(acc[-1] + h * fun(acc[-1], K=K, r=r)) # for autonomous system's only return np.array(acc), times K = 12 r = 0.43 Po = 1 N = 30; step_values = [1, 0.5, 0.1] fig = plt.figure() ax = fig.add_subplot(111) for h, c in zip(step_values, 'rgb'): Ps, Ts = euler(volterra, Po, h, N, K=K, r=r) ax.plot(Ts, Ps, c) plt.show( ) ``` « Next Oldest | Next Newest »

Top Page

 Possibly Related Threads... Thread Author Replies Views Last Post What is the use of call method and when to use it? everyday1 1 58 Jul-14-2019, 01:02 PM Last Post: ichabod801 Method not defined diskt 1 113 Jul-03-2019, 12:55 PM Last Post: noisefloor Graphing three database in one graph Python r_e 1 152 Jun-20-2019, 05:10 PM Last Post: r_e Method not regocnized Lass86 3 182 Jun-19-2019, 09:03 AM Last Post: Lass86 3rd problem from project Euler Richard_SS 6 272 Jun-05-2019, 02:06 PM Last Post: DeaD_EyE web3 method rembrandt 3 150 Jun-04-2019, 05:43 PM Last Post: buran [split] help with While method peterd1965 3 604 Jun-20-2018, 05:45 PM Last Post: volcano63 help with While method brawdhampshire 5 1,145 Jun-20-2018, 05:38 PM Last Post: micseydel need method to look up dictionary key by value league55 3 568 Jan-17-2018, 10:58 PM Last Post: metulburr Best Method for simple GUI? PythonAndArduino 4 1,056 Nov-17-2017, 06:22 AM Last Post: heiner55

Forum Jump:

Users browsing this thread: 1 Guest(s)