Questions tagged [sparse-operator]

Problems in which an operator or function can be represented with asymptotically less data than the naive representation. For questions that are specifically related to sparse matrices use [sparse-matrix] tag instead.

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Recover sparse matrix from linear operator

For many linear operators, it is easy to express them as a function. For example, to blur an image, simply compute a weighted sum of neighboring pixels (or even easier, import ...
John Doe's user avatar
3 votes
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Invert a huge sparse operator;

please help me with this question, I want to invert a huge sparse (non-circulant) this below in a $Ax=y$ equation: $$(\lambda I+ \beta D+ \sigma C)x=y$$ where I is an Identity Matrix,D is a Diagonal ...
Vy Trieu's user avatar
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When should I write a matrix-vector function to handle the sparse matrix vector multiplication?

This semster, I have been studying the iterative methods for large sparse matrix system. But I have some questions. For large sparse matrix, we must use an economic storage to store them. The most ...
Happy's user avatar
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6 votes
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Sparsity-Promoting Convex Optimization Over Simplex

Say we want to find a sparse approximate minimizer to the function $f(x) : \mathbb{R}^d \to \mathbb{R}$. Then in line with the work in the field of compressed sensing, we can instead minimize $$f(x) + ...
cdipaolo's user avatar
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9 votes
1 answer

preconditioner for a matrix-free method to solve Ax=b

I need to solve Ax=b, but I realize that even if it is sparse, storing the matrix coefficients of my problem will take too much memory. So now I'm considering using a matrix-free method, because the ...
nat chouf's user avatar
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