(git:6a2e663)
arnoldi_api Module Reference

arnoldi iteration using dbcsr More...

Functions/Subroutines

subroutine, public arnoldi_ev (matrix, arnoldi_data)
 Driver routine for different arnoldi eigenvalue methods the selection which one is to be taken is made beforehand in the setup call passing the generalized_ev flag or not. More...
 
subroutine, public arnoldi_extremal (matrix_a, max_ev, min_ev, converged, threshold, max_iter)
 simple wrapper to estimate extremal eigenvalues with arnoldi, using the old lanczos interface this hides some of the power of the arnoldi routines (e.g. only min or max eval, generalized eval, ritz vectors, etc.), and does not allow for providing an initial guess of the ritz vector. More...
 
subroutine, public arnoldi_conjugate_gradient (matrix_a, vec_x, matrix_p, converged, threshold, max_iter)
 Wrapper for conjugated gradient algorithm for Ax=b. More...
 

Detailed Description

arnoldi iteration using dbcsr

History
2014.09 created [Florian Schiffmann]
Author
Florian Schiffmann

Function/Subroutine Documentation

◆ arnoldi_ev()

subroutine, public arnoldi_api::arnoldi_ev ( type(dbcsr_p_type), dimension(:)  matrix,
type(arnoldi_data_type arnoldi_data 
)

Driver routine for different arnoldi eigenvalue methods the selection which one is to be taken is made beforehand in the setup call passing the generalized_ev flag or not.

Parameters
matrix...
arnoldi_data...

Definition at line 68 of file arnoldi_api.F.

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◆ arnoldi_extremal()

subroutine, public arnoldi_api::arnoldi_extremal ( type(dbcsr_type), intent(inout), target  matrix_a,
real(kind=dp), intent(out)  max_ev,
real(kind=dp), intent(out)  min_ev,
logical, intent(out)  converged,
real(kind=dp), intent(in)  threshold,
integer, intent(in)  max_iter 
)

simple wrapper to estimate extremal eigenvalues with arnoldi, using the old lanczos interface this hides some of the power of the arnoldi routines (e.g. only min or max eval, generalized eval, ritz vectors, etc.), and does not allow for providing an initial guess of the ritz vector.

Parameters
matrix_ainput mat
max_evestimated max eval
min_evestimated min eval
convergedUsually arnoldi is more accurate than claimed.
thresholdtarget precision
max_itermax allowed iterations (will be rounded up)

Definition at line 253 of file arnoldi_api.F.

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◆ arnoldi_conjugate_gradient()

subroutine, public arnoldi_api::arnoldi_conjugate_gradient ( type(dbcsr_type), intent(in), target  matrix_a,
real(kind=dp), dimension(:), intent(inout)  vec_x,
type(dbcsr_type), intent(in), optional, target  matrix_p,
logical, intent(out)  converged,
real(kind=dp), intent(in)  threshold,
integer, intent(in)  max_iter 
)

Wrapper for conjugated gradient algorithm for Ax=b.

Parameters
matrix_ainput mat
vec_xinput right hand side vector; output solution vector, fully replicated!
matrix_pinput preconditioner (optional)
converged...
thresholdtarget precision
max_itermax allowed iterations

Definition at line 302 of file arnoldi_api.F.

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