-
Notifications
You must be signed in to change notification settings - Fork 55
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
1 parent
9b536d9
commit 03f5f95
Showing
18 changed files
with
1,401 additions
and
30 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,227 @@ | ||
# [Block Krylov processes](@id block-krylov-processes) | ||
|
||
## [Block Hermitian Lanczos](@id block-hermitian-lanczos) | ||
|
||
If the vector $b$ in the [Hermitian Lanczos](@ref hermitian-lanczos) process is replaced by a matrix $B$ with $p$ columns, we can derive the block Hermitian Lanczos process. | ||
|
||
![block_hermitian_lanczos](./graphics/block_hermitian_lanczos.png) | ||
|
||
After $k$ iterations of the block Hermitian Lanczos process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A V_k &= V_{k+1} T_{k+1,k}, \\ | ||
V_k^H V_k &= I_{pk}, | ||
\end{align*} | ||
``` | ||
where $V_k$ is an orthonormal basis of the block Krylov subspace $\mathcal{K}_k^{\square}(A,B)$, | ||
```math | ||
T_{k+1,k} = | ||
\begin{bmatrix} | ||
\Omega_1 & \Psi_2^H & & \\ | ||
\Psi_2 & \Omega_2 & \ddots & \\ | ||
& \ddots & \ddots & \Psi_k^H \\ | ||
& & \Psi_k & \Omega_k \\ | ||
& & & \Psi_{k+1} | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`hermitian_lanczos`](@ref hermitian_lanczos(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $\Psi_1$ and $T_{k+1,k}$. | ||
|
||
```@docs | ||
hermitian_lanczos(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` | ||
|
||
## [Block Non-Hermitian Lanczos](@id block-nonhermitian-lanczos) | ||
|
||
If the vectors $b$ and $c$ in the [non-Hermitian Lanczos](@ref nonhermitian-lanczos) process are replaced by matrices $B$ and $C$ with both $p$ columns, we can derive the block non-Hermitian Lanczos process. | ||
|
||
![block_nonhermitian_lanczos](./graphics/block_nonhermitian_lanczos.png) | ||
|
||
After $k$ iterations of the block non-Hermitian Lanczos process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A V_k &= V_{k+1} T_{k+1,k}, \\ | ||
A^H U_k &= U_{k+1} T_{k,k+1}^H, \\ | ||
V_k^H U_k &= U_k^H V_k = I_{pk}, | ||
\end{align*} | ||
``` | ||
where $V_k$ and $U_k$ are bases of the block Krylov subspaces $\mathcal{K}^{\square}_k(A,B)$ and $\mathcal{K}^{\square}_k (A^H,C)$, respectively, | ||
```math | ||
T_{k+1,k} = | ||
\begin{bmatrix} | ||
\Omega_1 & \Phi_2 & & \\ | ||
\Psi_2 & \Omega_2 & \ddots & \\ | ||
& \ddots & \ddots & \Phi_k \\ | ||
& & \Psi_k & \Omega_k \\ | ||
& & & \Psi_{k+1} | ||
\end{bmatrix} | ||
, \qquad | ||
T_{k,k+1}^H = | ||
\begin{bmatrix} | ||
\Omega_1^H & \Psi_2^H & & \\ | ||
\Phi_2^H & \Omega_2^H & \ddots & \\ | ||
& \ddots & \ddots & \Psi_k^H \\ | ||
& & \Phi_k^H & \Omega_k^H \\ | ||
& & & \Phi_{k+1}^H | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`nonhermitian_lanczos`](@ref nonhermitian_lanczos(::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $\Psi_1$, $T_{k+1,k}$, $U_{k+1}$ $\Phi_1^H$ and $T_{k,k+1}^H$. | ||
|
||
```@docs | ||
nonhermitian_lanczos(::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` | ||
|
||
## [Block Arnoldi](@id block-arnoldi) | ||
|
||
If the vector $b$ in the [Arnoldi](@ref arnoldi) process is replaced by a matrix $B$ with $p$ columns, we can derive the block Arnoldi process. | ||
|
||
![block_arnoldi](./graphics/block_arnoldi.png) | ||
|
||
After $k$ iterations of the block Arnoldi process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A V_k &= V_{k+1} H_{k+1,k}, \\ | ||
V_k^H V_k &= I_{pk}, | ||
\end{align*} | ||
``` | ||
where $V_k$ is an orthonormal basis of the block Krylov subspace $\mathcal{K}_k^{\square}(A,B)$, | ||
```math | ||
H_{k+1,k} = | ||
\begin{bmatrix} | ||
\Psi_{1,1}~ & \Psi_{1,2}~ & \ldots & \Psi_{1,k} \\ | ||
\Psi_{2,1}~ & \ddots~ & \ddots & \vdots \\ | ||
& \ddots~ & \ddots & \Psi_{k-1,k} \\ | ||
& & \Psi_{k,k-1} & \Psi_{k,k} \\ | ||
& & & \Psi_{k+1,k} | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`arnoldi`](@ref arnoldi(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $\Gamma$, and $H_{k+1,k}$. | ||
|
||
```@docs | ||
arnoldi(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` | ||
|
||
## [Block Golub-Kahan](@id block-golub-kahan) | ||
|
||
If the vector $b$ in the [Golub-Kahan](@ref golub-kahan) process is replaced by a matrix $B$ with $p$ columns, we can derive the block Golub-Kahan process. | ||
|
||
![block_golub_kahan](./graphics/block_golub_kahan.png) | ||
|
||
After $k$ iterations of the block Golub-Kahan process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A V_k &= U_{k+1} B_k, \\ | ||
A^H U_{k+1} &= V_{k+1} L_{k+1}^H, \\ | ||
V_k^H V_k &= U_k^H U_k = I_{pk}, | ||
\end{align*} | ||
``` | ||
where $V_k$ and $U_k$ are bases of the block Krylov subspaces $\mathcal{K}_k^{\square}(A^HA,A^HB)$ and $\mathcal{K}_k^{\square}(AA^H,B)$, respectively, | ||
```math | ||
B_k = | ||
\begin{bmatrix} | ||
\Omega_1 & & & \\ | ||
\Psi_2 & \Omega_2 & & \\ | ||
& \ddots & \ddots & \\ | ||
& & \Psi_k & \Omega_k \\ | ||
& & & \Psi_{k+1} \\ | ||
\end{bmatrix} | ||
, \qquad | ||
L_{k+1}^H = | ||
\begin{bmatrix} | ||
\Omega_1^H & \Psi_2^H & & & \\ | ||
& \Omega_2^H & \ddots & & \\ | ||
& & \ddots & \Psi_k^H & \\ | ||
& & & \Omega_k^H & \Psi_{k+1}^H \\ | ||
& & & & \Omega_{k+1}^H \\ | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`golub_kahan`](@ref golub_kahan(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $U_{k+1}$, $\Psi_1$ and $L_{k+1}$. | ||
|
||
```@docs | ||
golub_kahan(::Any, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` | ||
|
||
## [Block Saunders-Simon-Yip](@id block-saunders-simon-yip) | ||
|
||
If the vectors $b$ and $c$ in the [Saunders-Simon-Yip](@ref saunders-simon-yip) process are replaced by matrices $B$ and $C$ with both $p$ columns, we can derive the block Saunders-Simon-Yip process. | ||
|
||
![block_saunders_simon_yip](./graphics/block_saunders_simon_yip.png) | ||
|
||
After $k$ iterations of the block Saunders-Simon-Yip process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A U_k &= V_{k+1} T_{k+1,k}, \\ | ||
A^H V_k &= U_{k+1} T_{k,k+1}^H, \\ | ||
V_k^H V_k &= U_k^H U_k = I_{pk}, | ||
\end{align*} | ||
``` | ||
where $\begin{bmatrix} V_k & 0 \\ 0 & U_k \end{bmatrix}$ is an orthonormal basis of the block Krylov subspace $\mathcal{K}^{\square}_k \left(\begin{bmatrix} 0 & A \\ A^H & 0 \end{bmatrix}, \begin{bmatrix} B & 0 \\ 0 & C \end{bmatrix}\right)$, | ||
```math | ||
T_{k+1,k} = | ||
\begin{bmatrix} | ||
\Omega_1 & \Phi_2 & & \\ | ||
\Psi_2 & \Omega_2 & \ddots & \\ | ||
& \ddots & \ddots & \Phi_k \\ | ||
& & \Psi_k & \Omega_k \\ | ||
& & & \Psi_{k+1} | ||
\end{bmatrix} | ||
, \qquad | ||
T_{k,k+1}^H = | ||
\begin{bmatrix} | ||
\Omega_1^H & \Psi_2^H & & \\ | ||
\Phi_2^H & \Omega_2^H & \ddots & \\ | ||
& \ddots & \ddots & \Psi_k^H \\ | ||
& & \Phi_k^H & \Omega_k^H \\ | ||
& & & \Phi_{k+1}^H | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`saunders_simon_yip`](@ref saunders_simon_yip(::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $\Psi_1$, $T_{k+1,k}$, $U_{k+1}$, $\Phi_1^H$ and $T_{k,k+1}^H$. | ||
|
||
```@docs | ||
saunders_simon_yip(::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` | ||
|
||
## [Block Montoison-Orban](@id block-montoison-orban) | ||
|
||
If the vectors $b$ and $c$ in the [Montoison-Orban](@ref montoison-orban) process are replaced by matrices $D$ and $C$ with both $p$ columns, we can derive the block Montoison-Orban process. | ||
|
||
![block_montoison_orban](./graphics/block_montoison_orban.png) | ||
|
||
After $k$ iterations of the block Montoison-Orban process, the situation may be summarized as | ||
```math | ||
\begin{align*} | ||
A U_k &= V_{k+1} H_{k+1,k}, \\ | ||
B V_k &= U_{k+1} F_{k+1,k}, \\ | ||
V_k^H V_k &= U_k^H U_k = I_{pk}, | ||
\end{align*} | ||
``` | ||
where $\begin{bmatrix} V_k & 0 \\ 0 & U_k \end{bmatrix}$ is an orthonormal basis of the block Krylov subspace $\mathcal{K}^{\square}_k \left(\begin{bmatrix} 0 & A \\ B & 0 \end{bmatrix}, \begin{bmatrix} D & 0 \\ 0 & C \end{bmatrix}\right)$, | ||
```math | ||
H_{k+1,k} = | ||
\begin{bmatrix} | ||
\Psi_{1,1}~ & \Psi_{1,2}~ & \ldots & \Psi_{1,k} \\ | ||
\Psi_{2,1}~ & \ddots~ & \ddots & \vdots \\ | ||
& \ddots~ & \ddots & \Psi_{k-1,k} \\ | ||
& & \Psi_{k,k-1} & \Psi_{k,k} \\ | ||
& & & \Psi_{k+1,k} | ||
\end{bmatrix} | ||
, \qquad | ||
F_{k+1,k} = | ||
\begin{bmatrix} | ||
\Phi_{1,1}~ & \Phi_{1,2}~ & \ldots & \Phi_{1,k} \\ | ||
\Phi_{2,1}~ & \ddots~ & \ddots & \vdots \\ | ||
& \ddots~ & \ddots & \Phi_{k-1,k} \\ | ||
& & \Phi_{k,k-1} & \Phi_{k,k} \\ | ||
& & & \Phi_{k+1,k} | ||
\end{bmatrix}. | ||
``` | ||
|
||
The function [`montoison_orban`](@ref montoison_orban(::Any, ::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat)) returns $V_{k+1}$, $\Gamma$, $H_{k+1,k}$, $U_{k+1}$, $\Lambda$, and $F_{k+1,k}$. | ||
|
||
```@docs | ||
montoison_orban(::Any, ::Any, ::AbstractMatrix{FC}, ::AbstractMatrix{FC}, ::Int) where FC <: (Union{Complex{T}, T} where T <: AbstractFloat) | ||
``` |
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.