Summary
Add a function to get the preconditioned initial residual from the iterative solvers in ReSolve.
Rationale
When using an iterative linear solver in SUNDIALS with the IDA solver, a function that returns the initial preconditioned residual $P^{-1}(b-Ax)$ is required.
Description
A getter for the initial residual vector in either SystemSolver or the iterative linear solver classes themselves.
Alternatively, this could be calculated in SUNDIALS, but it would require a Matvec operation.
Additional information
No response
Summary
Add a function to get the preconditioned initial residual from the iterative solvers in ReSolve.
Rationale
When using an iterative linear solver in SUNDIALS with the IDA solver, a function that returns the initial preconditioned residual$P^{-1}(b-Ax)$ is required.
Description
A getter for the initial residual vector in either SystemSolver or the iterative linear solver classes themselves.
Alternatively, this could be calculated in SUNDIALS, but it would require a Matvec operation.
Additional information
No response