lec17_ODE4 - #Lecture 17#Example 1 Lotka-Volterra#from...

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Unformatted text preview: #Lecture 17 ############# #Example 1: Lotka-Volterra ############## #from pylab import * # #def euler(x,y,tau): # for step in range(maxstep-1): # xc=x[step] # yc=y[step] # t=step*tau # times[step]=t # # #Compute accel. vector at each time step # fx=(a-b*xc-c*yc)*xc # fy=(-d+e*xc)*yc # # #Compute r and v for next time step # x[step+1]=xc+tau*fx # y[step+1]=yc+tau*fy # return x,y # #def leapfrog(x,y,tau): # for step in range(maxstep-1): # xc=x[step] # yc=y[step] # t=step*tau # times[step]=t # # #Compute accel. vector at each time step # # fy=(-d+e*xc)*yc # # #Compute y and x for next time step # y[step+1]=yc+tau*fy # # # Use updated y to compute new x (ala Euler-Cromer) # fx=(a-b*xc-c*y[step+1])*xc # x[step+1]=xc+tau*fx # # return x,y # # #close('all') # # # # ##parameters # #a=1 #prey birth rate #b=0.01 #prey death rate (other than being eaten) #c=1.4 #rate of consumption #d=12 #pred. death rate #e=0.4 #pred. growth rate # ##Initial conditions ##Y is predator population and x is prey population # #xsteady=d/e...
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This note was uploaded on 10/05/2010 for the course PHYS phy503 taught by Professor Gladden during the Spring '09 term at Ole Miss.

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lec17_ODE4 - #Lecture 17#Example 1 Lotka-Volterra#from...

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