SLASQ2(3F)SLASQ2(3F)NAMESLASQ2 - SLASQ2 computes the singular values of a real N-by-N unreduced
bidiagonal matrix with squared diagonal elements in Q and squared off-
diagonal elements in E
SYNOPSIS
SUBROUTINE SLASQ2( M, Q, E, QQ, EE, EPS, TOL2, SMALL2, SUP, KEND, INFO )
INTEGER INFO, KEND, M
REAL EPS, SMALL2, SUP, TOL2
REAL E( * ), EE( * ), Q( * ), QQ( * )
PURPOSESLASQ2 computes the singular values of a real N-by-N unreduced
bidiagonal matrix with squared diagonal elements in Q and
squared off-diagonal elements in E. The singular values are
computed to relative accuracy TOL, barring over/underflow or
denormalization.
ARGUMENTS
M (input) INTEGER
The number of rows and columns in the matrix. M >= 0.
Q (output) REAL array, dimension (M)
On normal exit, contains the squared singular values.
E (workspace) REAL array, dimension (M)
QQ (input/output) REAL array, dimension (M)
On entry, QQ contains the squared diagonal elements of the
bidiagonal matrix whose SVD is desired. On exit, QQ is
overwritten.
EE (input/output) REAL array, dimension (M)
On entry, EE(1:N-1) contains the squared off-diagonal elements of
the bidiagonal matrix whose SVD is desired. On exit, EE is
overwritten.
EPS (input) REAL
Machine epsilon.
TOL2 (input) REAL
Desired relative accuracy of computed eigenvalues as defined in
SLASQ1.
SMALL2 (input) REAL
A threshold value as defined in SLASQ1.
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SLASQ2(3F)SLASQ2(3F)
SUP (input/output) REAL
Upper bound for the smallest eigenvalue.
KEND (input/output) INTEGER
Index where minimum d occurs.
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the algorithm did not converge; i specifies
how many superdiagonals did not converge.
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