DBDT01 reconstructs a general matrix A from its bidiagonal form


    A = Q * B * P**T


 where Q (m by min(m,n)) and P**T (min(m,n) by n) are orthogonal


 matrices and B is bidiagonal.


 The test ratio to test the reduction is


    RESID = norm(A - Q * B * P**T) / ( n * norm(A) * EPS )


 where EPS is the machine precision.

M

          M is INTEGER


          The number of rows of the matrices A and Q.

N

          N is INTEGER


          The number of columns of the matrices A and P**T.

KD

          KD is INTEGER


          If KD = 0, B is diagonal and the array E is not referenced.


          If KD = 1, the reduction was performed by xGEBRD; B is upper


          bidiagonal if M >= N, and lower bidiagonal if M < N.


          If KD = -1, the reduction was performed by xGBBRD; B is


          always upper bidiagonal.

A

          A is DOUBLE PRECISION array, dimension (LDA,N)


          The m by n matrix A.

LDA

          LDA is INTEGER


          The leading dimension of the array A.  LDA >= max(1,M).

Q

          Q is DOUBLE PRECISION array, dimension (LDQ,N)


          The m by min(m,n) orthogonal matrix Q in the reduction


          A = Q * B * P**T.

LDQ

          LDQ is INTEGER


          The leading dimension of the array Q.  LDQ >= max(1,M).

D

          D is DOUBLE PRECISION array, dimension (min(M,N))


          The diagonal elements of the bidiagonal matrix B.

E

          E is DOUBLE PRECISION array, dimension (min(M,N)-1)


          The superdiagonal elements of the bidiagonal matrix B if


          m >= n, or the subdiagonal elements of B if m < n.

PT

          PT is DOUBLE PRECISION array, dimension (LDPT,N)


          The min(m,n) by n orthogonal matrix P**T in the reduction


          A = Q * B * P**T.

LDPT

          LDPT is INTEGER


          The leading dimension of the array PT.


          LDPT >= max(1,min(M,N)).

WORK

          WORK is DOUBLE PRECISION array, dimension (M+N)

RESID

          RESID is DOUBLE PRECISION


          The test ratio:


          norm(A - Q * B * P**T) / ( n * norm(A) * EPS )

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