Eigen: divida cada fila de matriz (escasa) por su elemento diagonal correspondiente
Using the Eigen library in C++, given a sparse matrix A, what is the most efficient way (row-wise operations? how to?) to compute a sparse matrix B tal que B(i, j) = A(i, j) / A(i, i) ? That is, divide each row i by the corresponding diagonal element A(i, i).
It would be helpful to know how to do it both in-place (replacing entries in A) and out-of-place (creating a new sparse matrix B).
My sparse matrix is defined as:
typedef double Real;
typedef Eigen::SparseMatrix<Real> SparseMatrixR;
Gracias,
m.
preguntado el 28 de mayo de 14 a las 13:05
Marco Di Benedetto
1 Respuestas
In other words you want to extract the diagonal of A, view it as a diagonal matrix, and apply its inverse to A:
A = A.diagonal().asDiagonal().inverse() * A;
This operation should be slightly more efficient if A is rowmajor.
contestado el 28 de mayo de 14 a las 13:05
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