indexing sparse gpuArrays?

2017 4 7
1 个回答
回答已采纳
更新时间：2017 4 13
6 次查看（30 天）

0 个投票

I have a sparse gpuArray (adj) and gpuArray A. Trying to execute
for i =1:length(A)
[~,c] = find(adj(A(i,1),:));
.
.
.
end
i get an error about matlab not allowing this way of indexing in sparse gpuArrays. After doing some search i understand that operator : inside adj(A(i,1),:) is causing the problem. Any suggestions of a solution or at least a way around this?

2 个评论
显示 无 隐藏 无

Matt J
Matt J 2017-4-7
编辑：Matt J 2017-4-7
Hmmm...I'd like to see what the rest of the loop is doing.
Charis L
Charis L 2017-4-7
the loop is supposed to find every triangle the edges stored in A, participate in, and adj is the adjacency matrix, but it never moves beyond the fist line.

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

Joss Knight
Joss Knight 2017-4-13

0 个投票

Generally if you are indexing scalar values in a sparse gpuArray then you're trying to do something very inefficient. Still, if you want the values in the j'th column of a sparse matrix you could go:
[I,J,V] = find(A);
j = 1;
ind = find(J==j);
Ij = I(ind);
Vj = V(ind);
Aj = zeros(size(A,1),1);
Aj(Ij) = Vj;
However, I get the impression that your A matrix is a column vector, in which case storing it as a sparse array is completely pointless since it saves you no space whatsoever. You may as well convert it to full.

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Sparse Matrices 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by