Move LAPACK trunk into position.

1 files changed, 101 insertions, 0 deletions

diff --git a/SRC/zlassq.f b/SRC/zlassq.f
new file mode 100644
index 00000000..a209984b
--- /dev/null
+++ b/SRC/zlassq.f
@@ -0,0 +1,101 @@
+      SUBROUTINE ZLASSQ( N, X, INCX, SCALE, SUMSQ )
+*
+*  -- LAPACK auxiliary routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+*     November 2006
+*
+*     .. Scalar Arguments ..
+      INTEGER            INCX, N
+      DOUBLE PRECISION   SCALE, SUMSQ
+*     ..
+*     .. Array Arguments ..
+      COMPLEX*16         X( * )
+*     ..
+*
+*  Purpose
+*  =======
+*
+*  ZLASSQ returns the values scl and ssq such that
+*
+*     ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,
+*
+*  where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is
+*  assumed to be at least unity and the value of ssq will then satisfy
+*
+*     1.0 .le. ssq .le. ( sumsq + 2*n ).
+*
+*  scale is assumed to be non-negative and scl returns the value
+*
+*     scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ),
+*            i
+*
+*  scale and sumsq must be supplied in SCALE and SUMSQ respectively.
+*  SCALE and SUMSQ are overwritten by scl and ssq respectively.
+*
+*  The routine makes only one pass through the vector X.
+*
+*  Arguments
+*  =========
+*
+*  N       (input) INTEGER
+*          The number of elements to be used from the vector X.
+*
+*  X       (input) COMPLEX*16 array, dimension (N)
+*          The vector x as described above.
+*             x( i )  = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.
+*
+*  INCX    (input) INTEGER
+*          The increment between successive values of the vector X.
+*          INCX > 0.
+*
+*  SCALE   (input/output) DOUBLE PRECISION
+*          On entry, the value  scale  in the equation above.
+*          On exit, SCALE is overwritten with the value  scl .
+*
+*  SUMSQ   (input/output) DOUBLE PRECISION
+*          On entry, the value  sumsq  in the equation above.
+*          On exit, SUMSQ is overwritten with the value  ssq .
+*
+* =====================================================================
+*
+*     .. Parameters ..
+      DOUBLE PRECISION   ZERO
+      PARAMETER          ( ZERO = 0.0D+0 )
+*     ..
+*     .. Local Scalars ..
+      INTEGER            IX
+      DOUBLE PRECISION   TEMP1
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          ABS, DBLE, DIMAG
+*     ..
+*     .. Executable Statements ..
+*
+      IF( N.GT.0 ) THEN
+         DO 10 IX = 1, 1 + ( N-1 )*INCX, INCX
+            IF( DBLE( X( IX ) ).NE.ZERO ) THEN
+               TEMP1 = ABS( DBLE( X( IX ) ) )
+               IF( SCALE.LT.TEMP1 ) THEN
+                  SUMSQ = 1 + SUMSQ*( SCALE / TEMP1 )**2
+                  SCALE = TEMP1
+               ELSE
+                  SUMSQ = SUMSQ + ( TEMP1 / SCALE )**2
+               END IF
+            END IF
+            IF( DIMAG( X( IX ) ).NE.ZERO ) THEN
+               TEMP1 = ABS( DIMAG( X( IX ) ) )
+               IF( SCALE.LT.TEMP1 ) THEN
+                  SUMSQ = 1 + SUMSQ*( SCALE / TEMP1 )**2
+                  SCALE = TEMP1
+               ELSE
+                  SUMSQ = SUMSQ + ( TEMP1 / SCALE )**2
+               END IF
+            END IF
+   10    CONTINUE
+      END IF
+*
+      RETURN
+*
+*     End of ZLASSQ
+*
+      END