summaryrefslogtreecommitdiff
path: root/SRC/zunml2.f
diff options
context:
space:
mode:
authorjason <jason@8a072113-8704-0410-8d35-dd094bca7971>2008-10-28 01:38:50 +0000
committerjason <jason@8a072113-8704-0410-8d35-dd094bca7971>2008-10-28 01:38:50 +0000
commitbaba851215b44ac3b60b9248eb02bcce7eb76247 (patch)
tree8c0f5c006875532a30d4409f5e94b0f310ff00a7 /SRC/zunml2.f
downloadlapack-baba851215b44ac3b60b9248eb02bcce7eb76247.tar.gz
lapack-baba851215b44ac3b60b9248eb02bcce7eb76247.tar.bz2
lapack-baba851215b44ac3b60b9248eb02bcce7eb76247.zip
Move LAPACK trunk into position.
Diffstat (limited to 'SRC/zunml2.f')
-rw-r--r--SRC/zunml2.f205
1 files changed, 205 insertions, 0 deletions
diff --git a/SRC/zunml2.f b/SRC/zunml2.f
new file mode 100644
index 00000000..cced4a77
--- /dev/null
+++ b/SRC/zunml2.f
@@ -0,0 +1,205 @@
+ SUBROUTINE ZUNML2( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,
+ $ WORK, INFO )
+*
+* -- LAPACK routine (version 3.1) --
+* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+* November 2006
+*
+* .. Scalar Arguments ..
+ CHARACTER SIDE, TRANS
+ INTEGER INFO, K, LDA, LDC, M, N
+* ..
+* .. Array Arguments ..
+ COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
+* ..
+*
+* Purpose
+* =======
+*
+* ZUNML2 overwrites the general complex m-by-n matrix C with
+*
+* Q * C if SIDE = 'L' and TRANS = 'N', or
+*
+* Q'* C if SIDE = 'L' and TRANS = 'C', or
+*
+* C * Q if SIDE = 'R' and TRANS = 'N', or
+*
+* C * Q' if SIDE = 'R' and TRANS = 'C',
+*
+* where Q is a complex unitary matrix defined as the product of k
+* elementary reflectors
+*
+* Q = H(k)' . . . H(2)' H(1)'
+*
+* as returned by ZGELQF. Q is of order m if SIDE = 'L' and of order n
+* if SIDE = 'R'.
+*
+* Arguments
+* =========
+*
+* SIDE (input) CHARACTER*1
+* = 'L': apply Q or Q' from the Left
+* = 'R': apply Q or Q' from the Right
+*
+* TRANS (input) CHARACTER*1
+* = 'N': apply Q (No transpose)
+* = 'C': apply Q' (Conjugate transpose)
+*
+* M (input) INTEGER
+* The number of rows of the matrix C. M >= 0.
+*
+* N (input) INTEGER
+* The number of columns of the matrix C. N >= 0.
+*
+* K (input) INTEGER
+* The number of elementary reflectors whose product defines
+* the matrix Q.
+* If SIDE = 'L', M >= K >= 0;
+* if SIDE = 'R', N >= K >= 0.
+*
+* A (input) COMPLEX*16 array, dimension
+* (LDA,M) if SIDE = 'L',
+* (LDA,N) if SIDE = 'R'
+* The i-th row must contain the vector which defines the
+* elementary reflector H(i), for i = 1,2,...,k, as returned by
+* ZGELQF in the first k rows of its array argument A.
+* A is modified by the routine but restored on exit.
+*
+* LDA (input) INTEGER
+* The leading dimension of the array A. LDA >= max(1,K).
+*
+* TAU (input) COMPLEX*16 array, dimension (K)
+* TAU(i) must contain the scalar factor of the elementary
+* reflector H(i), as returned by ZGELQF.
+*
+* C (input/output) COMPLEX*16 array, dimension (LDC,N)
+* On entry, the m-by-n matrix C.
+* On exit, C is overwritten by Q*C or Q'*C or C*Q' or C*Q.
+*
+* LDC (input) INTEGER
+* The leading dimension of the array C. LDC >= max(1,M).
+*
+* WORK (workspace) COMPLEX*16 array, dimension
+* (N) if SIDE = 'L',
+* (M) if SIDE = 'R'
+*
+* INFO (output) INTEGER
+* = 0: successful exit
+* < 0: if INFO = -i, the i-th argument had an illegal value
+*
+* =====================================================================
+*
+* .. Parameters ..
+ COMPLEX*16 ONE
+ PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) )
+* ..
+* .. Local Scalars ..
+ LOGICAL LEFT, NOTRAN
+ INTEGER I, I1, I2, I3, IC, JC, MI, NI, NQ
+ COMPLEX*16 AII, TAUI
+* ..
+* .. External Functions ..
+ LOGICAL LSAME
+ EXTERNAL LSAME
+* ..
+* .. External Subroutines ..
+ EXTERNAL XERBLA, ZLACGV, ZLARF
+* ..
+* .. Intrinsic Functions ..
+ INTRINSIC DCONJG, MAX
+* ..
+* .. Executable Statements ..
+*
+* Test the input arguments
+*
+ INFO = 0
+ LEFT = LSAME( SIDE, 'L' )
+ NOTRAN = LSAME( TRANS, 'N' )
+*
+* NQ is the order of Q
+*
+ IF( LEFT ) THEN
+ NQ = M
+ ELSE
+ NQ = N
+ END IF
+ IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
+ INFO = -1
+ ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
+ INFO = -2
+ ELSE IF( M.LT.0 ) THEN
+ INFO = -3
+ ELSE IF( N.LT.0 ) THEN
+ INFO = -4
+ ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
+ INFO = -5
+ ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
+ INFO = -7
+ ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
+ INFO = -10
+ END IF
+ IF( INFO.NE.0 ) THEN
+ CALL XERBLA( 'ZUNML2', -INFO )
+ RETURN
+ END IF
+*
+* Quick return if possible
+*
+ IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
+ $ RETURN
+*
+ IF( ( LEFT .AND. NOTRAN .OR. .NOT.LEFT .AND. .NOT.NOTRAN ) ) THEN
+ I1 = 1
+ I2 = K
+ I3 = 1
+ ELSE
+ I1 = K
+ I2 = 1
+ I3 = -1
+ END IF
+*
+ IF( LEFT ) THEN
+ NI = N
+ JC = 1
+ ELSE
+ MI = M
+ IC = 1
+ END IF
+*
+ DO 10 I = I1, I2, I3
+ IF( LEFT ) THEN
+*
+* H(i) or H(i)' is applied to C(i:m,1:n)
+*
+ MI = M - I + 1
+ IC = I
+ ELSE
+*
+* H(i) or H(i)' is applied to C(1:m,i:n)
+*
+ NI = N - I + 1
+ JC = I
+ END IF
+*
+* Apply H(i) or H(i)'
+*
+ IF( NOTRAN ) THEN
+ TAUI = DCONJG( TAU( I ) )
+ ELSE
+ TAUI = TAU( I )
+ END IF
+ IF( I.LT.NQ )
+ $ CALL ZLACGV( NQ-I, A( I, I+1 ), LDA )
+ AII = A( I, I )
+ A( I, I ) = ONE
+ CALL ZLARF( SIDE, MI, NI, A( I, I ), LDA, TAUI, C( IC, JC ),
+ $ LDC, WORK )
+ A( I, I ) = AII
+ IF( I.LT.NQ )
+ $ CALL ZLACGV( NQ-I, A( I, I+1 ), LDA )
+ 10 CONTINUE
+ RETURN
+*
+* End of ZUNML2
+*
+ END