how to Vectorize iterative '' coordinates transformation ''loop operation for speed

2 次查看（过去 30 天）
kamal wisal
kamal wisal 2018-9-7
评论： Matt J 2018-9-10
I want to transform local coordinates(tip positions) of a rotating blade into corresponding global coords. Tip coordinates and angular distance changes in time. which means there is a unique transformation matrix for every time step. hence i used loop to multiply transformation matrix (3*3) with local coords to get me global coords each time step. for accuracy reasons i need more than million transformations,which take more than 5 hours with my core i5 computer.its a 2D transformation. i need to vectorize only following part of the code.Please check attachment for complete code.
for i = 1: vec_size
M=[cos(theta_inst(i)) -sin(theta_inst(i)) dx(i);...
sin(theta_inst(i)) cos(theta_inst(i)) dy(i); ...
0 0 1]; %transformation matrix
glbl(1:3,i)= M*local(:,i); % dx,dy ~=0;
end

请先登录，再回答此问题。

采纳的回答

Matt J
Matt J 2018-9-7
编辑：Matt J 2018-9-7
In non-homogeneous coordinates,
c=cos(theta_inst(:)).'; s=sin(theta_inst(:)).';
dx=dx(:).'; dy=dy(:).';
L=local(1:2,:);
glbl = [ sum([c;-s].*L) ; sum([+s;c].*L) ]+[dx;dy] ;
  4 个评论
显示 2更早的评论
kamal wisal
kamal wisal 2018-9-8
yes. difference of outputs (global coords) as calculated by iterative process (for loop) and by vectorized operation using sum function.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Mathematics and Optimization 的更多信息

标签

产品


版本

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by