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c  along with this program; if not, write to the Free Software
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c  along with this program; if not, write to the Free Software
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c  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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c  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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c
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c
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c-----------------------------------------------------------------------
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c-----------------------------------------------------------------------
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c
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c
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c	ch2inv() computes the inverse of a positive-definite symmetric
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c ch2inv(x, ldx, n, v, info) computes the inverse of a positive-definite
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c	matrix from its choleski factorization.	 This can be used (for
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c		symmetric matrix from its choleski factorization.
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c	example) to compute the dispersion matrix for the estimated
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c This can be used, e.g., to compute the dispersion matrix for the estimated
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c	parameters in a regression analysis.
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c parameters in a regression analysis.
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c
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c
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c	On Entry
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c On Entry
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c
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c
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c	  x	    double precision(ldx,k)
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c	x	double precision(ldx,n)	 {ldx >= n}
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c		    the choleski decomposition or the
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c		the choleski decomposition or the qr decomposition
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c		    qr decomposition as computed by dqrdc
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c		as computed by dqrdc or dqrdc2.	 Only the
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c		    or dqrdc2
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c		UPPER TRIANGULAR part,	x(i,j), 1 <= i <= j <= n, is accessed.
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c
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c
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c	  ldx	    integer
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c	ldx	integer, ldx >= n
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c		    the leading dimension of the array x
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c		the leading dimension of the array x
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c
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c
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c	  n	    integer
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c	n	integer
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c		    the number of rows of the matrix x
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c		the number of rows and columns of the matrix x
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c
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c
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c	  k	    integer
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c On Return
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c		    the number of columns in the matrix k
 - 
 
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c
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c
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c	On Return
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c	v	double precision(n,n)
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c		the value of inverse(x'x)
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c
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c
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c	  v	    double precision(k,k)
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c		    the value of inverse(x'x)
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c
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c	This version dated Aug 24, 1996.
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c This version dated Aug 24, 1996.
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c	Ross Ihaka, University of Auckland.
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c Ross Ihaka, University of Auckland.
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c
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c
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      subroutine ch2inv(x, ldx, n, v, info)
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      subroutine ch2inv(x, ldx, n, v, info)
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c     implicit none
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c     implicit none
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      integer n, ldx, info
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      integer n, ldx, info
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      double precision x(ldx, n), v(n, n)
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      double precision x(ldx, n), v(n, n)