SUBROUTINE CQRDC(X,LDX,N,P,QRAUX,JPVT,WORK,JOB)
C***BEGIN PROLOGUE  CQRDC
C***DATE WRITTEN   780814   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  D5
C***KEYWORDS  COMPLEX,DECOMPOSITION,LINEAR ALGEBRA,LINPACK,MATRIX,
C             ORTHOGONAL TRIANGULAR
C***AUTHOR  STEWART, G. W., (U. OF MARYLAND)
C***PURPOSE  Uses Householder transformations to compute the QR factori-
C            zation of an N by P matrix X.  Column pivoting is optional.
C***DESCRIPTION
C
C     CQRDC uses Householder transformations to compute the QR
C     factorization of an N by P matrix X.  Column pivoting
C     based on the 2-norms of the reduced columns may be
C     performed at the users option.
C
C     On Entry
C
C        X       COMPLEX(LDX,P), where LDX .GE. N.
C                X contains the matrix whose decomposition is to be
C                computed.
C
C        LDX     INTEGER.
C                LDX is the leading dimension of the array X.
C
C        N       INTEGER.
C                N is the number of rows of the matrix X.
C
C        P       INTEGER.
C                P is the number of columns of the matrix X.
C
C        JVPT    INTEGER(P).
C                JVPT contains integers that control the selection
C                of the pivot columns.  The K-th column X(K) of X
C                is placed in one of three classes according to the
C                value of JVPT(K).
C
C                   If JVPT(K) .GT. 0, then X(K) is an initial
C                                      column.
C
C                   If JVPT(K) .EQ. 0, then X(K) is a free column.
C
C                   If JVPT(K) .LT. 0, then X(K) is a final column.
C
C                Before the decomposition is computed, initial columns
C                are moved to the beginning of the array X and final
C                columns to the end.  Both initial and final columns
C                are frozen in place during the computation and only
C                free columns are moved.  At the K-th stage of the
C                reduction, if X(K) is occupied by a free column
C                it is interchanged with the free column of largest
C                reduced norm.  JVPT is not referenced if
C                JOB .EQ. 0.
C
C        WORK    COMPLEX(P).
C                WORK is a work array.  WORK is not referenced if
C                JOB .EQ. 0.
C
C        JOB     INTEGER.
C                JOB is an integer that initiates column pivoting.
C                If JOB .EQ. 0, no pivoting is done.
C                If JOB .NE. 0, pivoting is done.
C
C     On Return
C
C        X       X contains in its upper triangle the upper
C                triangular matrix R of the QR factorization.
C                Below its diagonal X contains information from
C                which the unitary part of the decomposition
C                can be recovered.  Note that if pivoting has
C                been requested, the decomposition is not that
C                of the original matrix X but that of X
C                with its columns permuted as described by JVPT.
C
C        QRAUX   COMPLEX(P).
C                QRAUX contains further information required to recover
C                the unitary part of the decomposition.
C
C        JVPT    JVPT(K) contains the index of the column of the
C                original matrix that has been interchanged into
C                the K-th column, if pivoting was requested.
C
C     LINPACK.  This version dated 08/14/78 .
C     Stewart, G. W., University of Maryland, Argonne National Lab.
C
C     CQRDC uses the following functions and subprograms.
C
C     BLAS CAXPY,CDOTC,CSCAL,CSWAP,SCNRM2
C     Fortran ABS,AIMAG,AMAX1,CABS,CMPLX,CSQRT,MIN0,REAL
C***REFERENCES  DONGARRA J.J., BUNCH J.R., MOLER C.B., STEWART G.W.,
C                 *LINPACK USERS  GUIDE*, SIAM, 1979.
C***ROUTINES CALLED  CAXPY,CDOTC,CSCAL,CSWAP,SCNRM2
C***END PROLOGUE  CQRDC