Padé and Gregory error estimates for the logarithm of block triangular matrices
In this paper we give bounds for the error arising in the approximation of the logarithm of a block triangular matrix T by Padé approximants of the function f(x)=log[(1+x)/(1-x)] and partial sums of Gregory's series. These bounds show that if the norm of all diagonal blocks of the Cayley-transf...
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | article |
| Idioma: | eng |
| Publicado em: |
2006
|
| Assuntos: | |
| Texto completo: | http://hdl.handle.net/10316/4619 |
| País: | Portugal |
| Oai: | oai:estudogeral.sib.uc.pt:10316/4619 |
| Resumo: | In this paper we give bounds for the error arising in the approximation of the logarithm of a block triangular matrix T by Padé approximants of the function f(x)=log[(1+x)/(1-x)] and partial sums of Gregory's series. These bounds show that if the norm of all diagonal blocks of the Cayley-transform B=(T-I)(T+I)-1 is sufficiently close to zero, then both approximation methods are accurate. This will contribute for reducing the number of successive square roots of T needed in the inverse scaling and squaring procedure for the matrix logarithm. |
|---|