Krylov subspace

This is the motivation for building the Krylov subspace.

The resulting vectors are a basis of the Krylov subspace, .

The algorithm thus produces projections onto the Krylov subspace.

The method approximates the solution by the vector in a Krylov subspace with minimal residual.

In a large system, we may employ iterative methods such as Krylov subspace methods.

It is a Krylov subspace method.

It's a Krylov subspace method very similar to the much more popular conjugate gradient method, with similar construction and convergence properties.

SpectreRF now provides harmonic balance in addition to shooting methods, both of which are accelerated using Krylov subspace methods.

The application of preconditioned Krylov subspace methods allowed much larger systems to be solved, both in size of circuit and in numbers of harmonics.

All algorithms that work this way are referred to as Krylov subspace methods; they are among the most successful methods currently available in numerical linear algebra.

In 1931 he published a paper on what is now called the Krylov subspace and Krylov subspace methods.

The corresponding Krylov subspace method is the minimal residual method (MinRes) of Paige and Saunders.

Krylov subspace methods work by forming a basis of the sequence of successive matrix powers times the initial residual (the Krylov sequence).

For more general circuits, the method was considered impractical for all but these very small circuits until the mid-1990s, when Krylov subspace methods were applied to the problem.

Eventually the dominance of SpectreRF faded as the use of Krylov subspace methods propagated to other simulators, particularly those based on harmonic balance.

In the latter case, SPIKE is used as a preconditioner for iterative schemes like Krylov subspace methods and iterative refinement.

The idea of the Arnoldi iteration as an eigenvalue algorithm is to compute the eigenvalues of the orthogonal projection of A onto the Krylov subspace.

His main research interests are Krylov subspace methods, non-normal operators and spectral perturbation theory, Toeplitz matrices, random matrices, and damped wave operators.

Even in the trivial case and the resulting approximation with will be different from that obtained by the Lanczos algorithm, although both approximations will belong to the same Krylov subspace.

Such systems, particularly in 3D, are frequently too large for direct solvers, so iterative methods are used, either stationary methods such as successive overrelaxation or Krylov subspace methods.

In the case of a system of linear equations, the two main classes of iterative methods are the stationary iterative methods, and the more general Krylov subspace methods.

The matrix H can be viewed as the representation in the basis formed by the Arnoldi vectors of the orthogonal projection of A onto the Krylov subspace .

Theoretical results have shown that convergence improves with an increase in the Krylov subspace dimension n. However, an a-priori value of n which would lead to optimal convergence is not known.

The basis for the Krylov subspace is derived from the Cayley-Hamilton theorem which says that the inverse of a matrix can be found in terms of a linear combination of its powers.

It can be shown that there is no Krylov subspace method for general matrices, which is given by a short recurrence relation and yet minimizes the norms of the residuals, as GMRES does.