how to store big triangular matrix

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Anton 2014-8-8

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回答： Jan 2014-8-10

I need to store and operate(so time of referencing operations is very important) with thriangular matrix. How to do it effectively? I think that using of sparse matrix is not efficient because we need to store indexes. May be it is better to store as 1-d cell array of 1-d "normal" arrays? Or some other way? Please help. And sorry for my poor English

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Chris Turnes 2014-8-8

How large are your matrices? Can you fit the whole matrix in memory, and if not, can you fit only the non-zero coefficients in memory? Given the density of the matrix, you are correct that storing it as a sparse array will not be efficient. However, using a full matrix may still be your best option because of the efficiency of MATLAB's operations with triangular matrices.

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Answer 1

Jan 2014-8-10

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It depends on what you are doing with the matrices. When you only want to store the matrices, but do not perform any operations, a cell vector seems to be sufficient. When you need column or row operations only, this might be efficient also.

But e.g. for a matrix multiplication this would be a severe disadvantage and a full matrix is much better.