SHARE
TWEET

Untitled

a guest Mar 14th, 2019 85 Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. clear
  2. xdel(winsid());
  3.  
  4. x0 = 0;
  5. y0 = 1;
  6. xe = 2;
  7. ye = 2;
  8.  
  9. Nx = 5;
  10. x = linspace(x0,xe,Nx)';
  11. dx = x(2)-x(1);
  12.  
  13. function wyn = fa(x)
  14.     wyn = -sqrt(5)*x/6 + sqrt(1 + x.^2)/3 + (2+x.^2)/3;
  15. endfunction
  16.  
  17. function wyn = f1(x)  // elements of the main diagonal
  18.      wyn = 4*(1+x.^2)+2*dx^2;
  19. endfunction
  20.  
  21. function wyn = f2(x) // elements of the upper diagonal
  22.      wyn = 2*(1+x.^2)+x*dx;
  23. endfunction
  24.  
  25. function wyn = f3(x) // elements of the lower diagonal
  26.      wyn = 2*(1+x.^2)-x*dx;
  27. endfunction
  28.  
  29. function wyn = f4(x)   //elements of the right han d side vector
  30.      wyn = 2*x.^2*dx^2;
  31. endfunction
  32.  
  33. A = diag(-f1(x(2:$-1))) + diag(f2(x(2:$-2)), 1) + diag(f3(x(3:$-1)),-1);
  34.  
  35. b = f4(x(2:$-1));
  36. b(1) = b(1) - f3(x(2))*y0;
  37. b($) = b($) - f2(x($-1))*ye;
  38.  
  39. y = A\b;
  40. y=[y0;y;ye];
  41.  
  42. ya = fa(x);
  43. scf();
  44.  
  45. plot2d(x,y,style=5)
  46. plot2d(x,ya,style=2)
  47. xtitle(msprintf("Numerical and analytical aolutions, %d division",Nx));
  48. legend(['numerical','analytical'],2,%f);
  49.  
  50. scf();
  51. plot2d(x,y-ya,style=5)
  52. xtitle(msprintf("Absolute errors, %g divisions",Nx));
RAW Paste Data
We use cookies for various purposes including analytics. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy. OK, I Understand
 
Top