Matlab diary from CS 290H, Monday, May 12, 2014

This is /Users/gilbert/Documents/CS290hSpring2014/Matlab/startup.m
Starting diary file diary-12-May-2014.txt


> load PGPgiantcompo
> A = Problem.A;
> whos
  Name             Size                 Bytes  Class     Attributes

  A            10680x10680             863560  double    sparse    
  Problem          1x1                1037746  struct              

> A = laplacian(A);
> spy(A)

> d = sum(spones(A)) - 1;
> hist(d,100)
> max(d)
ans =
   205
> mean(d)
ans =
    4.5536
> sum(d==1)
ans =
        4229

> n = length(A)
n =
       10680
> b = rand(n,1);
> b = b - mean(b);
> sum(b)
ans =
   1.4038e-11

> [x, flag, relres, iter, resvec] = pcg(A,b,1e-6,n);
> iter
iter =
   640
> semilogy(resvec / resvec(1)),shg,hold on
> figure(2)
> R = chol(A);
> nnz(A)
ans =
       59312
> nnz(triu(A))
ans =
       34996
> spy(A)
> spy(R)

> clc
> close all

> [x, flag, relres, iter, resvec] = pcg(A,b,1e-6,n);
> norm(A*x-b)
ans =
   2.8163e-05

> figure
> semilogy(resvec / resvec(1)),shg,hold on
> xlabel('CG iteration')
> ylabel('residual reduction')
> title(sprintf('PGPgiantcompo: %d vertices, %d edges',length(A),nnz(triu(A))))
> shg

> D = diag(diag(A));
> [x, flag, relres, iter, resvec] = pcg(A,b,1e-6,n,D);
> semilogy(resvec / resvec(1),'g'),shg

> RR = cholinc(A,'0');
> [x, flag, relres, iter, resvec] = pcg(A,b,1e-6,n,RR',RR);
> semilogy(resvec / resvec(1),'r'),shg
> legend('no precond', 'Jacobi precond', 'IC precond'),shg
> shg



> diary off