Guest User

Untitled

a guest
Jul 23rd, 2019
72
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. # Newton–Raphson Method : algorithm for finding roots
  2. # ragulbalaji19
  3.  
  4. import math
  5.  
  6. def f(x): return pow(math.e,-x) + x * pow(math.e,-x) - 0.5 # function we want to study
  7. def fprime(x): return -(x * pow(math.e, -x)) # first derivative of said function
  8.  
  9. starting = [-0.5,0.0,0.5,3.0,3.449,3.5,5.0,6.0,7.0,10.0,40.0] # some starting points to start the process
  10.  
  11. for pt in starting:
  12. print("starting @",pt)
  13. ptn = pt
  14. for i in range(100): # TIMEOUT ARBITRARILY SET AT 100
  15. ptnold = ptn
  16. try:
  17. ptn = ptn - (f(ptn)/fprime(ptn))
  18. except Exception as e:
  19. print("DED", e)
  20. break;
  21. print(ptn)
  22. if abs(ptnold - ptn) < 0.0000001:
  23. print("CONVERGED.")
  24. break
  25. print("---\n")
RAW Paste Data