问题
I'm thinking of using Boost's Sparse Matrix for a computation where minimal memory usage is the goal. Unfortunately, the documentation page didn't include a discussion of the sparse matrix implementation's memory usage when I looked through it. Nor am I sure how to determine how much memory the sparse matrix is using at any given time.
How much memory will the sparse matrix use? Can you quote a source?
How can I find out how much memory the matrix is using at a given time t?
回答1:
I cannot give you an exact answer. But generally speaking a sparse matrix uses an amount of memory that is a multiple of the number of nonzero entries of the matrix. A common format stores all nonzero entries in an array 'A' (row by row). Stores than a second array 'B' which gives the column-index of the corresponding nonzero entry from 'A' and a third array telling me where in array 'A' row x begins. Assuming datatypes type_nnz, type_index a N*N sparse matrix with nnz nonzero elements the memory requirement is
sizeof(type_nnz)*nnz + sizeof(type_index)*(nnz+N)
来源：https://stackoverflow.com/questions/9284005/boost-sparse-matrix-memory-requirement