3. DESCRIPTION OF PROBLEM OR FUNCTION
EISPACK3 is a collection of 75 FORTRAN subroutines, both single- and double-precision, that compute the eigenvalues and eigenvectors of nine classes of matrices. The package can determine the eigensystem of complex general, complex Hermitian, real general, real symmetric, real symmetric band, real symmetric tridiagonal, special real tridiagonal, generalized real, and generalized real symmetric matrices. In addition, there are two routines which use the singular value decomposition to solve certain least squares problem. The individual subroutines are -
IDENTIFICATION DESCRIPTION
BAKVEC Back transform vectors of matrix formed by FIGI
BALANC Balance a real general matrix
BALBAK Back transform vectors of matrix formed by BALANC
BANDR Reduce sym. band matrix to sym. tridiag. matrix
BANDV Find some vectors of sym. band matrix
BISECT Find some values of sym. tridiag. matrix
BQR Find some values of sym. band matrix
CBABK2 Back transform vectors of matrix formed by CBAL
CBAL Balance a complex general matrix
CDIV Perform division of two complex quantities
CG Driver subroutine for a complex general matrix
CH Driver subroutine for a complex Hermitian matrix
CINVIT Find some vectors of complex Hess. matrix
COMBAK Back transform vectors of matrix formed by COMHES
COMHES Reduce complex matrix to complex Hess. (elementary)
COMLR Find all values of complex Hess. matrix (LR)
COMLR2 Find all values/vectors of cmplx Hess. matrix (LR)
CCMQR Find all values of complex Hessenberg matrix (QR)
COMQR2 Find all values/vectors of cmplx Hess. matrix (QR)
CORTB Back transform vectors of matrix formed by CORTH
CORTH Reduce complex matrix to complex Hess. (unitary)
CSROOT Find square root of complex quantity
ELMBAK Back transform vectors of matrix formed by ELMHES
ELMHES Reduce real matrix to real Hess. (elementary)
ELTRAN Accumulate transformations from ELMHES (for HQR2)
EPSLON Estimate unit roundoff relative to argument size
FIGI Reduce nonsym. tridiag. matrix to sym. tridiag.
FIGI2 Reduce nonsym. tridiag. matrix to sym. tridiag.
HQR Find all values of real Hess. matrix
HQR2 Find all values/vectors for real Hess. matrix
HTRIBK Back transform vectors of matrix formed by HTRIDI
HTRIB3 Back transform vectors of matrix formed by HTRID3
HTRIDI Reduce Hermitian matrix to sym. tridiag.
HTRID3 Reduce Hermitian packed matrix to sym. tridiag.
IMTQLV Find all values of sym. tridiag. matrix
IMTQL1 Find all values of sym. tridiag. matrix
IMTQL2 Find all values/vectors of sym. tridiag. matrix
INVIT Find some vectors of real Hess. matrix
MINFIT Singular value decomposition & least squares soln.
ORTBAK Back transform vectors of matrix formed by ORTHES
ORTHES Reduce real matrix to real Hess. (orthogonal)
ORTRAN Accumulate transformations from ORTHES (for HQR2)
PYTHAG Find square root of sum of squares of two quantities
QZHES Reduce real generalized matrix system
QZIT Further reduce real generalized matrix system
QZVAL Find all values of reduced real generalized system
QZVEC Find all vectors of real generalized matrix system
RATQR Find extreme values of sym. tridiag. matrix
REBAK Back transform vectors of matrix formed by REDUC
REBAKB Back transform vectors of matrix formed by REDUC2
REDUC Reduce sym. generalized matrix system to standard
REDUC2 Reduce sym. generalized matrix system to standard
RG Driver subroutine for a real general matrix
RGG Driver subroutine for a real generalized system
RS Driver subroutine for a real sym. matrix
RSB Driver subroutine for a real sym. band matrix
RSG Driver subroutine for real sym. generalized system
RSGAB Driver subroutine for real sym. generalized system
RSGBA Driver subroutine for real sym. generalized system
RSM Driver subroutine for a real symmetric matrix
RSP Driver subroutine for a real sym. packed matrix
RST Driver subroutine for a real sym. tridiag. matrix
RT Driver subroutine for a nonsym. tridiag. matrix
SVD Singular value decomposition of rectangular matrix
TINVIT Find some vectors of sym. tridiag. matrix
TQLRAT Find all values of sym. tridiag. matrix
TQL1 Find all values of sym. tridiag. matrix
TQL2 Find all values/vectors of sym. tridiag. matrix
TRBAK1 Back transform vectors of matrix formed by TRED1
TRBAK3 Back transform vectors of matrix formed by TRED3
TRED1 Reduce sym. matrix to sym. tridiag. matrix
TRED2 Reduce sym. matrix to sym. tridiag. matrix
TRED3 Reduce sym. packed matrix to sym. tridiag. matrix
TRIDIB Find some values of sym. tridiag. matrix
TSTURM Find some values/vectors of sym. tridiag. matrix