sbdt04.f3

!>
!> SBDT04 reconstructs a bidiagonal matrix B from its (partial) SVD:
!>    S = U' * B * V
!> where U and V are orthogonal matrices and S is diagonal.
!>
!> The test ratio to test the singular value decomposition is
!>    RESID = norm( S - U' * B * V ) / ( n * norm(B) * EPS )
!> where VT = V' and EPS is the machine precision.
!> 

UPLO

!>          UPLO is CHARACTER*1
!>          Specifies whether the matrix B is upper or lower bidiagonal.
!>          = 'U':  Upper bidiagonal
!>          = 'L':  Lower bidiagonal
!> 

N

!>          N is INTEGER
!>          The order of the matrix B.
!> 

D

!>          D is REAL array, dimension (N)
!>          The n diagonal elements of the bidiagonal matrix B.
!> 

E

!>          E is REAL array, dimension (N-1)
!>          The (n-1) superdiagonal elements of the bidiagonal matrix B
!>          if UPLO = 'U', or the (n-1) subdiagonal elements of B if
!>          UPLO = 'L'.
!> 

S

!>          S is REAL array, dimension (NS)
!>          The singular values from the (partial) SVD of B, sorted in
!>          decreasing order.
!> 

NS

!>          NS is INTEGER
!>          The number of singular values/vectors from the (partial)
!>          SVD of B.
!> 

U

!>          U is REAL array, dimension (LDU,NS)
!>          The n by ns orthogonal matrix U in S = U' * B * V.
!> 

LDU

!>          LDU is INTEGER
!>          The leading dimension of the array U.  LDU >= max(1,N)
!> 

VT

!>          VT is REAL array, dimension (LDVT,N)
!>          The n by ns orthogonal matrix V in S = U' * B * V.
!> 

LDVT

!>          LDVT is INTEGER
!>          The leading dimension of the array VT.
!> 

WORK

!>          WORK is REAL array, dimension (2*N)
!> 

RESID

!>          RESID is REAL
!>          The test ratio:  norm(S - U' * B * V) / ( n * norm(B) * EPS )
!> 

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