clavhe.f
来自「famous linear algebra library (LAPACK) p」· F 代码 · 共 511 行 · 第 1/2 页
F
511 行
40 CONTINUE
IF( K.LT.1 )
$ GO TO 60
*
* Test the pivot index. If greater than zero, a 1 x 1
* pivot was used, otherwise a 2 x 2 pivot was used.
*
IF( IPIV( K ).GT.0 ) THEN
*
* 1 x 1 pivot block:
*
* Multiply by the diagonal element if forming L * D.
*
IF( NOUNIT )
$ CALL CSCAL( NRHS, A( K, K ), B( K, 1 ), LDB )
*
* Multiply by P(K) * inv(L(K)) if K < N.
*
IF( K.NE.N ) THEN
KP = IPIV( K )
*
* Apply the transformation.
*
CALL CGERU( N-K, NRHS, ONE, A( K+1, K ), 1,
$ B( K, 1 ), LDB, B( K+1, 1 ), LDB )
*
* Interchange if a permutation was applied at the
* K-th step of the factorization.
*
IF( KP.NE.K )
$ CALL CSWAP( NRHS, B( K, 1 ), LDB, B( KP, 1 ), LDB )
END IF
K = K - 1
*
ELSE
*
* 2 x 2 pivot block:
*
* Multiply by the diagonal block if forming L * D.
*
IF( NOUNIT ) THEN
D11 = A( K-1, K-1 )
D22 = A( K, K )
D21 = A( K, K-1 )
D12 = CONJG( D21 )
DO 50 J = 1, NRHS
T1 = B( K-1, J )
T2 = B( K, J )
B( K-1, J ) = D11*T1 + D12*T2
B( K, J ) = D21*T1 + D22*T2
50 CONTINUE
END IF
*
* Multiply by P(K) * inv(L(K)) if K < N.
*
IF( K.NE.N ) THEN
*
* Apply the transformation.
*
CALL CGERU( N-K, NRHS, ONE, A( K+1, K ), 1,
$ B( K, 1 ), LDB, B( K+1, 1 ), LDB )
CALL CGERU( N-K, NRHS, ONE, A( K+1, K-1 ), 1,
$ B( K-1, 1 ), LDB, B( K+1, 1 ), LDB )
*
* Interchange if a permutation was applied at the
* K-th step of the factorization.
*
KP = ABS( IPIV( K ) )
IF( KP.NE.K )
$ CALL CSWAP( NRHS, B( K, 1 ), LDB, B( KP, 1 ), LDB )
END IF
K = K - 2
END IF
GO TO 40
60 CONTINUE
END IF
*--------------------------------------------------
*
* Compute B := A^H * B (conjugate transpose)
*
*--------------------------------------------------
ELSE
*
* Form B := U^H*B
* where U = P(m)*inv(U(m))* ... *P(1)*inv(U(1))
* and U^H = inv(U^H(1))*P(1)* ... *inv(U^H(m))*P(m)
*
IF( LSAME( UPLO, 'U' ) ) THEN
*
* Loop backward applying the transformations.
*
K = N
70 IF( K.LT.1 )
$ GO TO 90
*
* 1 x 1 pivot block.
*
IF( IPIV( K ).GT.0 ) THEN
IF( K.GT.1 ) THEN
*
* Interchange if P(K) != I.
*
KP = IPIV( K )
IF( KP.NE.K )
$ CALL CSWAP( NRHS, B( K, 1 ), LDB, B( KP, 1 ), LDB )
*
* Apply the transformation
* y = y - B' conjg(x),
* where x is a column of A and y is a row of B.
*
CALL CLACGV( NRHS, B( K, 1 ), LDB )
CALL CGEMV( 'Conjugate', K-1, NRHS, ONE, B, LDB,
$ A( 1, K ), 1, ONE, B( K, 1 ), LDB )
CALL CLACGV( NRHS, B( K, 1 ), LDB )
END IF
IF( NOUNIT )
$ CALL CSCAL( NRHS, A( K, K ), B( K, 1 ), LDB )
K = K - 1
*
* 2 x 2 pivot block.
*
ELSE
IF( K.GT.2 ) THEN
*
* Interchange if P(K) != I.
*
KP = ABS( IPIV( K ) )
IF( KP.NE.K-1 )
$ CALL CSWAP( NRHS, B( K-1, 1 ), LDB, B( KP, 1 ),
$ LDB )
*
* Apply the transformations
* y = y - B' conjg(x),
* where x is a block column of A and y is a block
* row of B.
*
CALL CLACGV( NRHS, B( K, 1 ), LDB )
CALL CGEMV( 'Conjugate', K-2, NRHS, ONE, B, LDB,
$ A( 1, K ), 1, ONE, B( K, 1 ), LDB )
CALL CLACGV( NRHS, B( K, 1 ), LDB )
*
CALL CLACGV( NRHS, B( K-1, 1 ), LDB )
CALL CGEMV( 'Conjugate', K-2, NRHS, ONE, B, LDB,
$ A( 1, K-1 ), 1, ONE, B( K-1, 1 ), LDB )
CALL CLACGV( NRHS, B( K-1, 1 ), LDB )
END IF
*
* Multiply by the diagonal block if non-unit.
*
IF( NOUNIT ) THEN
D11 = A( K-1, K-1 )
D22 = A( K, K )
D12 = A( K-1, K )
D21 = CONJG( D12 )
DO 80 J = 1, NRHS
T1 = B( K-1, J )
T2 = B( K, J )
B( K-1, J ) = D11*T1 + D12*T2
B( K, J ) = D21*T1 + D22*T2
80 CONTINUE
END IF
K = K - 2
END IF
GO TO 70
90 CONTINUE
*
* Form B := L^H*B
* where L = P(1)*inv(L(1))* ... *P(m)*inv(L(m))
* and L^H = inv(L^H(m))*P(m)* ... *inv(L^H(1))*P(1)
*
ELSE
*
* Loop forward applying the L-transformations.
*
K = 1
100 CONTINUE
IF( K.GT.N )
$ GO TO 120
*
* 1 x 1 pivot block
*
IF( IPIV( K ).GT.0 ) THEN
IF( K.LT.N ) THEN
*
* Interchange if P(K) != I.
*
KP = IPIV( K )
IF( KP.NE.K )
$ CALL CSWAP( NRHS, B( K, 1 ), LDB, B( KP, 1 ), LDB )
*
* Apply the transformation
*
CALL CLACGV( NRHS, B( K, 1 ), LDB )
CALL CGEMV( 'Conjugate', N-K, NRHS, ONE, B( K+1, 1 ),
$ LDB, A( K+1, K ), 1, ONE, B( K, 1 ), LDB )
CALL CLACGV( NRHS, B( K, 1 ), LDB )
END IF
IF( NOUNIT )
$ CALL CSCAL( NRHS, A( K, K ), B( K, 1 ), LDB )
K = K + 1
*
* 2 x 2 pivot block.
*
ELSE
IF( K.LT.N-1 ) THEN
*
* Interchange if P(K) != I.
*
KP = ABS( IPIV( K ) )
IF( KP.NE.K+1 )
$ CALL CSWAP( NRHS, B( K+1, 1 ), LDB, B( KP, 1 ),
$ LDB )
*
* Apply the transformation
*
CALL CLACGV( NRHS, B( K+1, 1 ), LDB )
CALL CGEMV( 'Conjugate', N-K-1, NRHS, ONE,
$ B( K+2, 1 ), LDB, A( K+2, K+1 ), 1, ONE,
$ B( K+1, 1 ), LDB )
CALL CLACGV( NRHS, B( K+1, 1 ), LDB )
*
CALL CLACGV( NRHS, B( K, 1 ), LDB )
CALL CGEMV( 'Conjugate', N-K-1, NRHS, ONE,
$ B( K+2, 1 ), LDB, A( K+2, K ), 1, ONE,
$ B( K, 1 ), LDB )
CALL CLACGV( NRHS, B( K, 1 ), LDB )
END IF
*
* Multiply by the diagonal block if non-unit.
*
IF( NOUNIT ) THEN
D11 = A( K, K )
D22 = A( K+1, K+1 )
D21 = A( K+1, K )
D12 = CONJG( D21 )
DO 110 J = 1, NRHS
T1 = B( K, J )
T2 = B( K+1, J )
B( K, J ) = D11*T1 + D12*T2
B( K+1, J ) = D21*T1 + D22*T2
110 CONTINUE
END IF
K = K + 2
END IF
GO TO 100
120 CONTINUE
END IF
*
END IF
RETURN
*
* End of CLAVHE
*
END
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