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Ublas : |
From: Jesse Manning (manning.jesse_at_[hidden])
Date: 2007-11-30 12:29:58
In visual studio 2003 .NET (MSVC 7.1) when I compiled in release mode which
uses #define NDEBUG and optimizes for maximum speed the time reported by the
program was 0.141 seconds which I consider to be fast.
the command line for release mode looks like this:
/O2 /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_MBCS" /FD /EHsc /ML /GS
/Fo"Release/" /Fd"Release/vc70.pdb" /W3 /nologo /c /Wp64 /Zi /TP
To me it looks like you just need to tweak your compiler settings and it
will run much faster.
good luck,
Jesse
On Nov 30, 2007 12:03 PM, nisha kannookadan <nishak44_at_[hidden]> wrote:
>
> Hey everybody
>
> Finally I got to the ublas mailing list and I hope u guys can help me.
> Im quite new with boost and everything else than an expert.
>
> Im programming in C++ and have to translate a program from matlab
> to C++. I did it, but my program is way to slow.
>
> I got already suggestions from the boost users and developpers:
> - to do pass by refernce
> - define DNDEBUG
> - to compile with full optimization
> - to use bindings (but I dont think, I need it, since its not high level
> matrix stuff)
> - and that I should go to post the question here :).
>
> I did some of the changes already and it got little better, but its still
> bad.
>
> The program is quite huge, so I took a part out of it, which is now even
> runnable
> for you.
> I post here the maltab and c++ code, so u maybe can help me.
>
> 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
>
>
> Id be so thankful for any help.
> Bye
> Nisha K
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