Hi guys Thanks for all. I follow your advises, posted the code in the ublas, gonna read a C++ book and Im positive, its gonna be fine. I changed now the code to something runnable and have it also in matlab, u will see, its way slower in C++. So first C++: #include #include "MVHF.h" #include #include #include #include #include #define DNDEBUG #include using namespace std; void ttrans(matrix& At, int level) { matrix cfe1, cfe2, cfo, cfe, c, d; int N,s2; N = (At.size1()+1)/2; s2 = At.size2(); zero_matrix zer(N,s2); for (int ii = 1; ii <= level; ii++) { cfo = subslice(At, 0,2,N, 0,1,s2); cfe = subslice(At, 1,2,N-1, 0,1,s2); c = cfe + (subrange(cfo, 0,N-1, 0,s2)+subrange(cfo, 1,N, 0,s2))*0.5; zer.resize(N,s2,true); cfe1 = zer; cfe2 = zer; (subrange(cfe1, 0,N-1, 0,s2)).assign(cfe); (subrange(cfe2, 1,N, 0,s2)).assign(cfe); d = cfo-(cfe1+cfe2)*0.5; (subrange(At, 0,N-1, 0,At.size2())).assign(c); (subrange(At, N-1,2*N-1, 0,At.size2())).assign(d); N = N/2; } } void init(int dom,int llev) { int in_dofs_LA= 511; matrix Am_LA, As_LA; double mesh_size = ((double)(dom)/(in_dofs_LA+1)); scalar_matrix zer(in_dofs_LA, in_dofs_LA,0.0); Am_LA.resize(in_dofs_LA, in_dofs_LA, false); As_LA.resize(in_dofs_LA, in_dofs_LA, false); Am_LA.assign(zer); As_LA.assign(zer); Am_LA(0,0) = 4.0; Am_LA(1,0) = 1.0; As_LA(0,0) = 2.0; As_LA(1,0) = -1.0; for (int ii = 1; ii < (in_dofs_LA-1); ii++){ Am_LA(ii-1,ii) = 1.0; Am_LA(ii,ii) = 4.0; Am_LA(ii+1,ii) = 1.0; As_LA(ii-1,ii) = -1.0; As_LA(ii,ii) = 2.0; As_LA(ii+1,ii) = -1.0; } Am_LA(in_dofs_LA-2,in_dofs_LA-1) = 1.0; Am_LA(in_dofs_LA-1,in_dofs_LA-1) = 4.0; As_LA(in_dofs_LA-2,in_dofs_LA-1) = -1.0; As_LA(in_dofs_LA-1,in_dofs_LA-1) = 2.0; Am_LA = Am_LA*(mesh_size/6.0); As_LA = As_LA*(1.0/mesh_size); ttrans(Am_LA,llev); Am_LA = trans(Am_LA); ttrans(Am_LA,llev); Am_LA = trans(Am_LA); ttrans(As_LA,llev); As_LA = trans(As_LA); ttrans(As_LA,llev); As_LA = trans(As_LA); } int main() { clock_t start, end; start = clock(); init(1,8); end = clock(); std::cout << " " << std::endl; std::cout << "Elapsed time is " << (double)(end-start)/CLOCKS_PER_SEC << "." << std::endl; } Here the matlab version of it: function test() tic R = 1; L = 8; n = 2^(L+1)-1; h = R/(n+1); e = ones(n,1); Am = h/6*spdiags([e, 4*e, e], -1:1, n, n); % compute stiffness matrix As = 1/h*spdiags([-e, 2*e, -e], -1:1, n, n); % transform into wavelets Am = ttrans(ttrans(Am,L)',L)'; As = ttrans(ttrans(As,L)',L)'; toc return function cd = ttrans(cl,L) N = size(cl,1)+1; N = N/2; m = size(cl,2); z = zeros(1,m); cd = cl; for i=1:L cfo = cd(1:2:2*N-1,:); cfe = cd(2:2:2*N-2,:); % wavelets c = cfe + (cfo(1:end-1,:)+cfo(2:end,:))/2; d = cfo - ([cfe;z]+[z;cfe])/2; cd(1:2*N-1,:) = [c;d]; N = N/2; end return But I really gotta say, this mailing list is great. I really appreciate all of your replies. Thanks, Nisha K _________________________________________________________________ News, entertainment and everything you care about at Live.com. Get it now! http://www.live.com/getstarted.aspx