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cgelss.f(3)				      LAPACK				      cgelss.f(3)

NAME
       cgelss.f -

SYNOPSIS
   Functions/Subroutines
       subroutine cgelss (M, N, NRHS, A, LDA, B, LDB, S, RCOND, RANK, WORK, LWORK, RWORK, INFO)
	    CGELSS solves overdetermined or underdetermined systems for GE matrices

Function/Subroutine Documentation
   subroutine cgelss (integerM, integerN, integerNRHS, complex, dimension( lda, * )A, integerLDA,
       complex, dimension( ldb, * )B, integerLDB, real, dimension( * )S, realRCOND, integerRANK,
       complex, dimension( * )WORK, integerLWORK, real, dimension( * )RWORK, integerINFO)
	CGELSS solves overdetermined or underdetermined systems for GE matrices

       Purpose:

	    CGELSS computes the minimum norm solution to a complex linear
	    least squares problem:

	    Minimize 2-norm(| b - A*x |).

	    using the singular value decomposition (SVD) of A. A is an M-by-N
	    matrix which may be rank-deficient.

	    Several right hand side vectors b and solution vectors x can be
	    handled in a single call; they are stored as the columns of the
	    M-by-NRHS right hand side matrix B and the N-by-NRHS solution matrix
	    X.

	    The effective rank of A is determined by treating as zero those
	    singular values which are less than RCOND times the largest singular
	    value.

       Parameters:
	   M

		     M is INTEGER
		     The number of rows of the matrix A. M >= 0.

	   N

		     N is INTEGER
		     The number of columns of the matrix A. N >= 0.

	   NRHS

		     NRHS is INTEGER
		     The number of right hand sides, i.e., the number of columns
		     of the matrices B and X. NRHS >= 0.

	   A

		     A is COMPLEX array, dimension (LDA,N)
		     On entry, the M-by-N matrix A.
		     On exit, the first min(m,n) rows of A are overwritten with
		     its right singular vectors, stored rowwise.

	   LDA

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

	   B

		     B is COMPLEX array, dimension (LDB,NRHS)
		     On entry, the M-by-NRHS right hand side matrix B.
		     On exit, B is overwritten by the N-by-NRHS solution matrix X.
		     If m >= n and RANK = n, the residual sum-of-squares for
		     the solution in the i-th column is given by the sum of
		     squares of the modulus of elements n+1:m in that column.

	   LDB

		     LDB is INTEGER
		     The leading dimension of the array B.  LDB >= max(1,M,N).

	   S

		     S is REAL array, dimension (min(M,N))
		     The singular values of A in decreasing order.
		     The condition number of A in the 2-norm = S(1)/S(min(m,n)).

	   RCOND

		     RCOND is REAL
		     RCOND is used to determine the effective rank of A.
		     Singular values S(i) <= RCOND*S(1) are treated as zero.
		     If RCOND < 0, machine precision is used instead.

	   RANK

		     RANK is INTEGER
		     The effective rank of A, i.e., the number of singular values
		     which are greater than RCOND*S(1).

	   WORK

		     WORK is COMPLEX array, dimension (MAX(1,LWORK))
		     On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

	   LWORK

		     LWORK is INTEGER
		     The dimension of the array WORK. LWORK >= 1, and also:
		     LWORK >=  2*min(M,N) + max(M,N,NRHS)
		     For good performance, LWORK should generally be larger.

		     If LWORK = -1, then a workspace query is assumed; the routine
		     only calculates the optimal size of the WORK array, returns
		     this value as the first entry of the WORK array, and no error
		     message related to LWORK is issued by XERBLA.

	   RWORK

		     RWORK is REAL array, dimension (5*min(M,N))

	   INFO

		     INFO is INTEGER
		     = 0:  successful exit
		     < 0:  if INFO = -i, the i-th argument had an illegal value.
		     > 0:  the algorithm for computing the SVD failed to converge;
			   if INFO = i, i off-diagonal elements of an intermediate
			   bidiagonal form did not converge to zero.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 178 of file cgelss.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			      cgelss.f(3)
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