I am working with a very sparse matrix and it seems inefficient to load the full matrix as input into the Qiskit HHL algorithm. Is it possible to input only the non-zero elements, instead ? I am working with a "clean" banded, tri-diagonal matrix.
At the moment this is not possible, however in the near future it will be possible for the case of tridiagonal symmetric Toeplitz matrices.
The reason for this being that qiskit does not support QRAM or "black-box" access to the matrix elements, so to be able to partly specify the matrix one would need to develop specific methods that work with this limited information, which is only possible if the matrix has some structure.