zqrt12()

double precision function zqrt12	(	integer	M,
		integer	N,
		complex*16, dimension( lda, * )	A,
		integer	LDA,
		double precision, dimension( * )	S,
		complex*16, dimension( lwork )	WORK,
		integer	LWORK,
		double precision, dimension( * )	RWORK
	)

ZQRT12

Purpose:

 ZQRT12 computes the singular values `svlues' of the upper trapezoid
 of A(1:M,1:N) and returns the ratio

      || s - svlues||/(||svlues||*eps*max(M,N))

Parameters

[in]	M	M is INTEGER The number of rows of the matrix A.
[in]	N	N is INTEGER The number of columns of the matrix A.
[in]	A	A is COMPLEX*16 array, dimension (LDA,N) The M-by-N matrix A. Only the upper trapezoid is referenced.
[in]	LDA	LDA is INTEGER The leading dimension of the array A.
[in]	S	S is DOUBLE PRECISION array, dimension (min(M,N)) The singular values of the matrix A.
[out]	WORK	WORK is COMPLEX*16 array, dimension (LWORK)
[in]	LWORK	LWORK is INTEGER The length of the array WORK. LWORK >= M*N + 2*min(M,N) + max(M,N).
[out]	RWORK	RWORK is DOUBLE PRECISION array, dimension (2*min(M,N))

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.