tps/chap3/jjm.py

   1 from math import *
   2
   3 def f(x):
   4     return cos(x)-x
   5
   6
   7 def iteration_lagrange(x0, q0, m, epsilon, f):
   8     def maj_test(xn,xnm1):
   9         return f(xn)!=0 and abs(xn-xnm1)>epsilon
  10
  11     n=0
  12     test=f(x0)!=0
  13     X=[x0]
  14     xnm1=x0
  15     xn=float(x0-f(x0))/q0
  16     qn=q0
  17     print(xn,q0)
  18     while n<=m and test:
  19         qn=float((f(xn)-f(xnm1)))/(xn-xnm1)
  20         xnm1=xn
  21         xn=xnm1-f(xnm1)/qn
  22
  23         X+=[xn]
  24         test=maj_test(xn,xnm1)
  25         n+=1
  26     return (n,X)
  27
  28 print(iteration_lagrange(pi/4,1,200,0.0000001,f))
  29
  30
  31 def iteration_lagrange(x0, x1, m, epsilon, f):
  32     def maj_test(xn,xnm1):
  33         return f(xn)!=0 and abs(xn-xnm1)>epsilon
  34
  35     n=2
  36     test=f(x0)!=0
  37     X=[x0,x1]
  38     xnm1=x0
  39     xn=x1
  40     while n<=m and test:
  41         qn=float((f(xn)-f(xnm1)))/(xn-xnm1)
  42         xnm1=xn
  43         xn=xnm1-f(xnm1)/qn
  44
  45         X+=[xn]
  46         test=maj_test(xn,xnm1)
  47         n+=1
  48     return (n,X)
  49
  50
  51
  52 print(iteration_lagrange(0,pi/4,200,0.0000001,f))