belajar_quiver

quiver.py

# -*- coding: utf-8 -*-
"""
Created on Sat Mar 10 20:33:32 2012

@author: fajar
"""
from numpy import linspace, meshgrid, array
import pylab as pl
from scipy.integrate import odeint

# membuat vektor
u = linspace(-5,5,21)
v = linspace(-5,5,21)
U,V = meshgrid(u,v)
def fu(u,v):
    return u
def fv(u,v):
    return -2*v
FU = fu(U,V)
FV = fv(U,V)

# sistem Persamaan:
def g(x,t):
    y1 = x[0]
    y2 = -2*x[1] 
    return [y1, y2]
    
time = linspace(0,1,100)
con = array([[1.5,3],[1.5,-3],[-1.5,3],[-1.5,-3]])
pl.figure()
Q = pl.quiver(U,V,FU,FV, units='height', hold=True)

sol = odeint(g, con[0], time)
pl.plot(sol[:,0], sol[:,1], linewidth=2.1 , color='y')

sol = odeint(g, con[1], time)
pl.plot(sol[:,0], sol[:,1], linewidth=2.1,color='b')

sol = odeint(g,  con[2], time)
pl.plot(sol[:,0], sol[:,1], linewidth=2.1 , color='m')

sol = odeint(g,  con[3], time)
pl.plot(sol[:,0], sol[:,1], linewidth=2.1 , color='r')

pl.autoscale(enable=True,axis='Both', tight =True)
pl.xlabel('u', weight='bold')
pl.ylabel('v', weight='bold')
pl.title('u\'=u dan v\'=-2v',weight='bold')
pl.show()