C%% TRUNCATED-NEWTON METHOD: BLAS
C   NOTE: ALL ROUTINES HERE ARE FROM LINPACK WITH THE EXCEPTION
C         OF DXPY (A VERSION OF DAXPY WITH A=1.0)
C   WRITTEN BY:  STEPHEN G. NASH
C                OPERATIONS RESEARCH AND APPLIED STATISTICS DEPT.
C                GEORGE MASON UNIVERSITY
C                FAIRFAX, VA 22030
C****************************************************************
      DOUBLE PRECISION FUNCTION DDOT(N,DX,INCX,DY,INCY)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
C
C     FORMS THE DOT PRODUCT OF TWO VECTORS.
C     USES UNROLLED LOOPS FOR INCREMENTS EQUAL TO ONE.
C     JACK DONGARRA, LINPACK, 3/11/78.
C
      DOUBLE PRECISION DX(1),DY(1),DTEMP
      INTEGER I,INCX,INCY,IX,IY,M,MP1,N
C
      DDOT = 0.0D0
      DTEMP = 0.0D0
      IF(N.LE.0)RETURN
      IF(INCX.EQ.1.AND.INCY.EQ.1)GO TO 20
C
C        CODE FOR UNEQUAL INCREMENTS OR EQUAL INCREMENTS
C          NOT EQUAL TO 1
C
      IX = 1
      IY = 1
      IF(INCX.LT.0)IX = (-N+1)*INCX + 1
      IF(INCY.LT.0)IY = (-N+1)*INCY + 1
      DO 10 I = 1,N
        DTEMP = DTEMP + DX(IX)*DY(IY)
        IX = IX + INCX
        IY = IY + INCY
   10 CONTINUE
      DDOT = DTEMP
      RETURN
C
C        CODE FOR BOTH INCREMENTS EQUAL TO 1
C
C
C        CLEAN-UP LOOP
C
   20 M = MOD(N,5)
      IF( M .EQ. 0 ) GO TO 40
      DO 30 I = 1,M
        DTEMP = DTEMP + DX(I)*DY(I)
   30 CONTINUE
      IF( N .LT. 5 ) GO TO 60
   40 MP1 = M + 1
      DO 50 I = MP1,N,5
        DTEMP = DTEMP + DX(I)*DY(I) + DX(I + 1)*DY(I + 1) +
     *   DX(I + 2)*DY(I + 2) + DX(I + 3)*DY(I + 3) + DX(I + 4)*DY(I + 4)
   50 CONTINUE
   60 DDOT = DTEMP
      RETURN
      END
      SUBROUTINE DAXPY(N,DA,DX,INCX,DY,INCY)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
C
C     CONSTANT TIMES A VECTOR PLUS A VECTOR.
C     USES UNROLLED LOOPS FOR INCREMENTS EQUAL TO ONE.
C     JACK DONGARRA, LINPACK, 3/11/78.
C
      DOUBLE PRECISION DX(1),DY(1),DA
      INTEGER I,INCX,INCY,IX,IY,M,MP1,N
C
      IF(N.LE.0)RETURN
      IF (DA .EQ. 0.0D0) RETURN
      IF(INCX.EQ.1.AND.INCY.EQ.1)GO TO 20
C
C        CODE FOR UNEQUAL INCREMENTS OR EQUAL INCREMENTS
C          NOT EQUAL TO 1
C
      IX = 1
      IY = 1
      IF(INCX.LT.0)IX = (-N+1)*INCX + 1
      IF(INCY.LT.0)IY = (-N+1)*INCY + 1
      DO 10 I = 1,N
        DY(IY) = DY(IY) + DA*DX(IX)
        IX = IX + INCX
        IY = IY + INCY
   10 CONTINUE
      RETURN
C
C        CODE FOR BOTH INCREMENTS EQUAL TO 1
C
C
C        CLEAN-UP LOOP
C
   20 M = MOD(N,4)
      IF( M .EQ. 0 ) GO TO 40
      DO 30 I = 1,M
        DY(I) = DY(I) + DA*DX(I)
   30 CONTINUE
      IF( N .LT. 4 ) RETURN
   40 MP1 = M + 1
      DO 50 I = MP1,N,4
        DY(I) = DY(I) + DA*DX(I)
        DY(I + 1) = DY(I + 1) + DA*DX(I + 1)
        DY(I + 2) = DY(I + 2) + DA*DX(I + 2)
        DY(I + 3) = DY(I + 3) + DA*DX(I + 3)
   50 CONTINUE
      RETURN
      END
      DOUBLE PRECISION FUNCTION DNRM2 ( N, DX, INCX)
      IMPLICIT         DOUBLE PRECISION (A-H,O-Z)
      INTEGER          NEXT
      DOUBLE PRECISION DX(1),CUTLO,CUTHI,HITEST,SUM,XMAX,ZERO,ONE
      DATA   ZERO, ONE /0.0D0, 1.0D0/
C
C     EUCLIDEAN NORM OF THE N-VECTOR STORED IN DX() WITH STORAGE
C     INCREMENT INCX .
C     IF    N .LE. 0 RETURN WITH RESULT = 0.
C     IF N .GE. 1 THEN INCX MUST BE .GE. 1
C
C           C.L.LAWSON, 1978 JAN 08
C
C     FOUR PHASE METHOD     USING TWO BUILT-IN CONSTANTS THAT ARE
C     HOPEFULLY APPLICABLE TO ALL MACHINES.
C         CUTLO = MAXIMUM OF  DSQRT(U/EPS)  OVER ALL KNOWN MACHINES.
C         CUTHI = MINIMUM OF  DSQRT(V)      OVER ALL KNOWN MACHINES.
C     WHERE
C         EPS = SMALLEST NO. SUCH THAT EPS + 1. .GT. 1.
C         U   = SMALLEST POSITIVE NO.   (UNDERFLOW LIMIT)
C         V   = LARGEST  NO.            (OVERFLOW  LIMIT)
C
C     BRIEF OUTLINE OF ALGORITHM..
C
C     PHASE 1    SCANS ZERO COMPONENTS.
C     MOVE TO PHASE 2 WHEN A COMPONENT IS NONZERO AND .LE. CUTLO
C     MOVE TO PHASE 3 WHEN A COMPONENT IS .GT. CUTLO
C     MOVE TO PHASE 4 WHEN A COMPONENT IS .GE. CUTHI/M
C     WHERE M = N FOR X() REAL AND M = 2*N FOR COMPLEX.
C
C     VALUES FOR CUTLO AND CUTHI..
C     FROM THE ENVIRONMENTAL PARAMETERS LISTED IN THE IMSL CONVERTER
C     DOCUMENT THE LIMITING VALUES ARE AS FOLLOWS..
C     CUTLO, S.P.   U/EPS = 2**(-102) FOR  HONEYWELL.  CLOSE SECONDS ARE
C                   UNIVAC AND DEC AT 2**(-103)
C                   THUS CUTLO = 2**(-51) = 4.44089E-16
C     CUTHI, S.P.   V = 2**127 FOR UNIVAC, HONEYWELL, AND DEC.
C                   THUS CUTHI = 2**(63.5) = 1.30438E19
C     CUTLO, D.P.   U/EPS = 2**(-67) FOR HONEYWELL AND DEC.
C                   THUS CUTLO = 2**(-33.5) = 8.23181D-11
C     CUTHI, D.P.   SAME AS S.P.  CUTHI = 1.30438D19
C     DATA CUTLO, CUTHI / 8.232D-11,  1.304D19 /
C     DATA CUTLO, CUTHI / 4.441E-16,  1.304E19 /
      DATA CUTLO, CUTHI / 8.232D-11,  1.304D19 /
C
      IF(N .GT. 0) GO TO 10
         DNRM2  = ZERO
         GO TO 300
C
   10 ASSIGN 30 TO NEXT
      SUM = ZERO
      NN = N * INCX
C                                                 BEGIN MAIN LOOP
      I = 1
   20    GO TO NEXT,(30, 50, 70, 110)
   30 IF( DABS(DX(I)) .GT. CUTLO) GO TO 85
      ASSIGN 50 TO NEXT
      XMAX = ZERO
C
C                        PHASE 1.  SUM IS ZERO
C
   50 IF( DX(I) .EQ. ZERO) GO TO 200
      IF( DABS(DX(I)) .GT. CUTLO) GO TO 85
C
C                                PREPARE FOR PHASE 2.
      ASSIGN 70 TO NEXT
      GO TO 105
C
C                                PREPARE FOR PHASE 4.
C
  100 I = J
      ASSIGN 110 TO NEXT
      SUM = (SUM / DX(I)) / DX(I)
  105 XMAX = DABS(DX(I))
      GO TO 115
C
C                   PHASE 2.  SUM IS SMALL.
C                             SCALE TO AVOID DESTRUCTIVE UNDERFLOW.
C
   70 IF( DABS(DX(I)) .GT. CUTLO ) GO TO 75
C
C                     COMMON CODE FOR PHASES 2 AND 4.
C                     IN PHASE 4 SUM IS LARGE.  SCALE TO AVOID OVERFLOW.
C
  110 IF( DABS(DX(I)) .LE. XMAX ) GO TO 115
         SUM = ONE + SUM * (XMAX / DX(I))**2
         XMAX = DABS(DX(I))
         GO TO 200
C
  115 SUM = SUM + (DX(I)/XMAX)**2
      GO TO 200
C
C
C                  PREPARE FOR PHASE 3.
C
   75 SUM = (SUM * XMAX) * XMAX
C
C
C     FOR REAL OR D.P. SET HITEST = CUTHI/N
C     FOR COMPLEX      SET HITEST = CUTHI/(2*N)
C
   85 HITEST = CUTHI/FLOAT( N )
C
C                   PHASE 3.  SUM IS MID-RANGE.  NO SCALING.
C
      DO 95 J =I,NN,INCX
      IF(DABS(DX(J)) .GE. HITEST) GO TO 100
   95    SUM = SUM + DX(J)**2
      DNRM2 = DSQRT( SUM )
      GO TO 300
C
  200 CONTINUE
      I = I + INCX
      IF ( I .LE. NN ) GO TO 20
C
C              END OF MAIN LOOP.
C
C              COMPUTE SQUARE ROOT AND ADJUST FOR SCALING.
C
      DNRM2 = XMAX * DSQRT(SUM)
  300 CONTINUE
      RETURN
      END
      SUBROUTINE DCOPY(N,DX,INCX,DY,INCY)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
C
C     COPIES A VECTOR, X, TO A VECTOR, Y.
C     USES UNROLLED LOOPS FOR INCREMENTS EQUAL TO ONE.
C     JACK DONGARRA, LINPACK, 3/11/78.
C
      DOUBLE PRECISION DX(1),DY(1)
      INTEGER I,INCX,INCY,IX,IY,M,MP1,N
C
      IF(N.LE.0)RETURN
      IF(INCX.EQ.1.AND.INCY.EQ.1)GO TO 20
C
C        CODE FOR UNEQUAL INCREMENTS OR EQUAL INCREMENTS
C          NOT EQUAL TO 1
C
      IX = 1
      IY = 1
      IF(INCX.LT.0)IX = (-N+1)*INCX + 1
      IF(INCY.LT.0)IY = (-N+1)*INCY + 1
      DO 10 I = 1,N
        DY(IY) = DX(IX)
        IX = IX + INCX
        IY = IY + INCY
   10 CONTINUE
      RETURN
C
C        CODE FOR BOTH INCREMENTS EQUAL TO 1
C
C
C        CLEAN-UP LOOP
C
   20 M = MOD(N,7)
      IF( M .EQ. 0 ) GO TO 40
      DO 30 I = 1,M
        DY(I) = DX(I)
   30 CONTINUE
      IF( N .LT. 7 ) RETURN
   40 MP1 = M + 1
      DO 50 I = MP1,N,7
        DY(I) = DX(I)
        DY(I + 1) = DX(I + 1)
        DY(I + 2) = DX(I + 2)
        DY(I + 3) = DX(I + 3)
        DY(I + 4) = DX(I + 4)
        DY(I + 5) = DX(I + 5)
        DY(I + 6) = DX(I + 6)
   50 CONTINUE
      RETURN
      END
C******************************************************************
C SPECIAL BLAS FOR Y = X+Y
C******************************************************************
      SUBROUTINE DXPY(N,DX,INCX,DY,INCY)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
C
C     VECTOR PLUS A VECTOR.
C     USES UNROLLED LOOPS FOR INCREMENTS EQUAL TO ONE.
C     STEPHEN G. NASH 5/30/89.
C
      DOUBLE PRECISION DX(1),DY(1)
      INTEGER I,INCX,INCY,IX,IY,M,MP1,N
C
      IF(N.LE.0)RETURN
      IF(INCX.EQ.1.AND.INCY.EQ.1)GO TO 20
C
C        CODE FOR UNEQUAL INCREMENTS OR EQUAL INCREMENTS
C          NOT EQUAL TO 1
C
      IX = 1
      IY = 1
      IF(INCX.LT.0)IX = (-N+1)*INCX + 1
      IF(INCY.LT.0)IY = (-N+1)*INCY + 1
      DO 10 I = 1,N
        DY(IY) = DY(IY) + DX(IX)
        IX = IX + INCX
        IY = IY + INCY
   10 CONTINUE
      RETURN
C
C        CODE FOR BOTH INCREMENTS EQUAL TO 1
C
C
C        CLEAN-UP LOOP
C
   20 M = MOD(N,4)
      IF( M .EQ. 0 ) GO TO 40
      DO 30 I = 1,M
        DY(I) = DY(I) + DX(I)
   30 CONTINUE
      IF( N .LT. 4 ) RETURN
   40 MP1 = M + 1
      DO 50 I = MP1,N,4
        DY(I) = DY(I) + DX(I)
        DY(I + 1) = DY(I + 1) + DX(I + 1)
        DY(I + 2) = DY(I + 2) + DX(I + 2)
        DY(I + 3) = DY(I + 3) + DX(I + 3)
   50 CONTINUE
      RETURN
      END
