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From: someone on 23 Jun 2010 17:24
"brufl-andi " <ameinel(a)ufl.edu> wrote in message <hvtrf6$8o3$1(a)fred.mathworks.com>...
> Hey,
>
> I have written the following function which contains a lot of loops. Now I want to vectorize it in terms of improving the performance of the program.

Vectorizing to remove loops does not NECESSARILY improve performance.
A lot depends on the size of your matricies and the available memory.

> In general the created structure array contains 9 matrices. Every entry of the matrix is calculated by the function sim_cpv_elem_vec, whereas p and q are points and not vectors!
>
> It would be great if anybody has a general idea how to create a system of matrices whereas every single entry has to be calculated by a complex function.
>
>
> function [C] =create_sim_defl( vol )
>
> %input values:
> % - vol.cond containing the conductivities of the three compartments
> % - vol.bnd(k).pnt is a Nx3 matrix which contains nodal points of a triangulated surface
> % - vol.bnd(k).tri is the corresponding Mx3 matrix which contains the indeces line by line of the nodal points representing a triangle on the surface
>
>
> Omega=0;
> p_defl=1/size(vol.bnd(ncmp).pnt,1); %addend which is needed for the deflation technique
>
> %preallocation
>
> for k=1:3
> for l=1:3
> k_size=size(vol.bnd(k).pnt); %the size of each matrix is determined by the number of vertices on
> l_size=size(vol.bnd(l).pnt);
> C(k,l).mat=zeros([k_size(1),l_size(1)]);% preallocating the 3x3 structure array
> C(k,l).size=[k_size(1),l_size(1)];
>
> end
> end
>
>
> for k=1:3
> for l=1:3
> prefac=(1/(2*pi))*((vol.cond(l)-vol.cond(l+1))/(vol.cond(k)+vol.cond(k+1))); % this is a constant factor depending only on k and l!
> for p=1:C(k,l).size(1)
> for q=1:C(k,l).size(2)
> b=sim_cpv_elem_vec(p,q,vol.bnd(k).pnt,vol.bnd(l).pnt, vol.bnd(l).tri);
> if l==3
> C(k,l).mat(p,q)=prefac*b-p_defl;
> else
> C(k,l).mat(p,q)=prefac*b;
> end
> end
> end
>
> end
> end
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