search for: dsyevx

Displaying 2 results from an estimated 2 matches for "dsyevx".

Did you mean: dsyevr
2004 Nov 05
1
fast partial spectral decompositions.
hello, i want to compute the top k eigenvalues+eigenvectors of a (large) real symmetric matrix. since it doesn't look like any top-level R function does this, i'll call LAPACK from a C shlib and then use .Call. the only LAPACK function i see to do this in R_ext/Lapack.h is dsyevx. however, i know that in LAPACK dsyevr can also return a partial eigendecomposition. why is dsyevr not exported in R_ext/Lapack.h? my superficial understanding is that dsyevr is "better" (faster? stabler?) for both complete and partial eigenproblems than dsyevd/dsyevx, but only the comple...
2004 Nov 05
1
fast partial spectral decompositions.
hello, i want to compute the top k eigenvalues+eigenvectors of a (large) real symmetric matrix. since it doesn't look like any top-level R function does this, i'll call LAPACK from a C shlib and then use .Call. the only LAPACK function i see to do this in R_ext/Lapack.h is dsyevx. however, i know that in LAPACK dsyevr can also return a partial eigendecomposition. why is dsyevr not exported in R_ext/Lapack.h? my superficial understanding is that dsyevr is "better" (faster? stabler?) for both complete and partial eigenproblems than dsyevd/dsyevx, but only the comple...