Which is faster, the sparse or spdiag function?
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In each iteration of a for loop I'm creating a big (approximatlly 10k*10k) five diagonal sparse matrix. Does anybody knows which function work faster? The sparse or spdiags. Is there a faster way to it if I only update the values of an existing sparse matrix in each iteration?
2 个评论
Walter Roberson
2018-4-10
Be careful, updating an existing sparse matrix is slow if you are adding non-zero elements beyond what was allocated for the matrix with spalloc()
James Tursa
2018-4-10
Even if you are not exceeding the currently allocated memory for the matrix, it can be slow if the operation causes a large number of existing elements to be moved around in this memory.
回答（1 个）
Walter Roberson
2018-4-10
0 个投票
spdiags() invokes sparse() after packaging together the appropriate content and indices.
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