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| author | jofret | 2009-04-28 07:17:00 +0000 |
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| committer | jofret | 2009-04-28 07:17:00 +0000 |
| commit | 8c8d2f518968ce7057eec6aa5cd5aec8faab861a (patch) | |
| tree | 3dd1788b71d6a3ce2b73d2d475a3133580e17530 /src/lib/lapack/dsytd2.f | |
| parent | 9f652ffc16a310ac6641a9766c5b9e2671e0e9cb (diff) | |
| download | scilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.tar.gz scilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.tar.bz2 scilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.zip | |
Moving lapack to right place
Diffstat (limited to 'src/lib/lapack/dsytd2.f')
| -rw-r--r-- | src/lib/lapack/dsytd2.f | 248 |
1 files changed, 0 insertions, 248 deletions
diff --git a/src/lib/lapack/dsytd2.f b/src/lib/lapack/dsytd2.f deleted file mode 100644 index c696818e..00000000 --- a/src/lib/lapack/dsytd2.f +++ /dev/null @@ -1,248 +0,0 @@ - SUBROUTINE DSYTD2( UPLO, N, A, LDA, D, E, TAU, INFO ) -* -* -- LAPACK routine (version 3.1) -- -* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. -* November 2006 -* -* .. Scalar Arguments .. - CHARACTER UPLO - INTEGER INFO, LDA, N -* .. -* .. Array Arguments .. - DOUBLE PRECISION A( LDA, * ), D( * ), E( * ), TAU( * ) -* .. -* -* Purpose -* ======= -* -* DSYTD2 reduces a real symmetric matrix A to symmetric tridiagonal -* form T by an orthogonal similarity transformation: Q' * A * Q = T. -* -* Arguments -* ========= -* -* UPLO (input) CHARACTER*1 -* Specifies whether the upper or lower triangular part of the -* symmetric matrix A is stored: -* = 'U': Upper triangular -* = 'L': Lower triangular -* -* N (input) INTEGER -* The order of the matrix A. N >= 0. -* -* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) -* On entry, the symmetric matrix A. If UPLO = 'U', the leading -* n-by-n upper triangular part of A contains the upper -* triangular part of the matrix A, and the strictly lower -* triangular part of A is not referenced. If UPLO = 'L', the -* leading n-by-n lower triangular part of A contains the lower -* triangular part of the matrix A, and the strictly upper -* triangular part of A is not referenced. -* On exit, if UPLO = 'U', the diagonal and first superdiagonal -* of A are overwritten by the corresponding elements of the -* tridiagonal matrix T, and the elements above the first -* superdiagonal, with the array TAU, represent the orthogonal -* matrix Q as a product of elementary reflectors; if UPLO -* = 'L', the diagonal and first subdiagonal of A are over- -* written by the corresponding elements of the tridiagonal -* matrix T, and the elements below the first subdiagonal, with -* the array TAU, represent the orthogonal matrix Q as a product -* of elementary reflectors. See Further Details. -* -* LDA (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,N). -* -* D (output) DOUBLE PRECISION array, dimension (N) -* The diagonal elements of the tridiagonal matrix T: -* D(i) = A(i,i). -* -* E (output) DOUBLE PRECISION array, dimension (N-1) -* The off-diagonal elements of the tridiagonal matrix T: -* E(i) = A(i,i+1) if UPLO = 'U', E(i) = A(i+1,i) if UPLO = 'L'. -* -* TAU (output) DOUBLE PRECISION array, dimension (N-1) -* The scalar factors of the elementary reflectors (see Further -* Details). -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value. -* -* Further Details -* =============== -* -* If UPLO = 'U', the matrix Q is represented as a product of elementary -* reflectors -* -* Q = H(n-1) . . . H(2) H(1). -* -* Each H(i) has the form -* -* H(i) = I - tau * v * v' -* -* where tau is a real scalar, and v is a real vector with -* v(i+1:n) = 0 and v(i) = 1; v(1:i-1) is stored on exit in -* A(1:i-1,i+1), and tau in TAU(i). -* -* If UPLO = 'L', the matrix Q is represented as a product of elementary -* reflectors -* -* Q = H(1) H(2) . . . H(n-1). -* -* Each H(i) has the form -* -* H(i) = I - tau * v * v' -* -* where tau is a real scalar, and v is a real vector with -* v(1:i) = 0 and v(i+1) = 1; v(i+2:n) is stored on exit in A(i+2:n,i), -* and tau in TAU(i). -* -* The contents of A on exit are illustrated by the following examples -* with n = 5: -* -* if UPLO = 'U': if UPLO = 'L': -* -* ( d e v2 v3 v4 ) ( d ) -* ( d e v3 v4 ) ( e d ) -* ( d e v4 ) ( v1 e d ) -* ( d e ) ( v1 v2 e d ) -* ( d ) ( v1 v2 v3 e d ) -* -* where d and e denote diagonal and off-diagonal elements of T, and vi -* denotes an element of the vector defining H(i). -* -* ===================================================================== -* -* .. Parameters .. - DOUBLE PRECISION ONE, ZERO, HALF - PARAMETER ( ONE = 1.0D0, ZERO = 0.0D0, - $ HALF = 1.0D0 / 2.0D0 ) -* .. -* .. Local Scalars .. - LOGICAL UPPER - INTEGER I - DOUBLE PRECISION ALPHA, TAUI -* .. -* .. External Subroutines .. - EXTERNAL DAXPY, DLARFG, DSYMV, DSYR2, XERBLA -* .. -* .. External Functions .. - LOGICAL LSAME - DOUBLE PRECISION DDOT - EXTERNAL LSAME, DDOT -* .. -* .. Intrinsic Functions .. - INTRINSIC MAX, MIN -* .. -* .. Executable Statements .. -* -* Test the input parameters -* - INFO = 0 - UPPER = LSAME( UPLO, 'U' ) - IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN - INFO = -1 - ELSE IF( N.LT.0 ) THEN - INFO = -2 - ELSE IF( LDA.LT.MAX( 1, N ) ) THEN - INFO = -4 - END IF - IF( INFO.NE.0 ) THEN - CALL XERBLA( 'DSYTD2', -INFO ) - RETURN - END IF -* -* Quick return if possible -* - IF( N.LE.0 ) - $ RETURN -* - IF( UPPER ) THEN -* -* Reduce the upper triangle of A -* - DO 10 I = N - 1, 1, -1 -* -* Generate elementary reflector H(i) = I - tau * v * v' -* to annihilate A(1:i-1,i+1) -* - CALL DLARFG( I, A( I, I+1 ), A( 1, I+1 ), 1, TAUI ) - E( I ) = A( I, I+1 ) -* - IF( TAUI.NE.ZERO ) THEN -* -* Apply H(i) from both sides to A(1:i,1:i) -* - A( I, I+1 ) = ONE -* -* Compute x := tau * A * v storing x in TAU(1:i) -* - CALL DSYMV( UPLO, I, TAUI, A, LDA, A( 1, I+1 ), 1, ZERO, - $ TAU, 1 ) -* -* Compute w := x - 1/2 * tau * (x'*v) * v -* - ALPHA = -HALF*TAUI*DDOT( I, TAU, 1, A( 1, I+1 ), 1 ) - CALL DAXPY( I, ALPHA, A( 1, I+1 ), 1, TAU, 1 ) -* -* Apply the transformation as a rank-2 update: -* A := A - v * w' - w * v' -* - CALL DSYR2( UPLO, I, -ONE, A( 1, I+1 ), 1, TAU, 1, A, - $ LDA ) -* - A( I, I+1 ) = E( I ) - END IF - D( I+1 ) = A( I+1, I+1 ) - TAU( I ) = TAUI - 10 CONTINUE - D( 1 ) = A( 1, 1 ) - ELSE -* -* Reduce the lower triangle of A -* - DO 20 I = 1, N - 1 -* -* Generate elementary reflector H(i) = I - tau * v * v' -* to annihilate A(i+2:n,i) -* - CALL DLARFG( N-I, A( I+1, I ), A( MIN( I+2, N ), I ), 1, - $ TAUI ) - E( I ) = A( I+1, I ) -* - IF( TAUI.NE.ZERO ) THEN -* -* Apply H(i) from both sides to A(i+1:n,i+1:n) -* - A( I+1, I ) = ONE -* -* Compute x := tau * A * v storing y in TAU(i:n-1) -* - CALL DSYMV( UPLO, N-I, TAUI, A( I+1, I+1 ), LDA, - $ A( I+1, I ), 1, ZERO, TAU( I ), 1 ) -* -* Compute w := x - 1/2 * tau * (x'*v) * v -* - ALPHA = -HALF*TAUI*DDOT( N-I, TAU( I ), 1, A( I+1, I ), - $ 1 ) - CALL DAXPY( N-I, ALPHA, A( I+1, I ), 1, TAU( I ), 1 ) -* -* Apply the transformation as a rank-2 update: -* A := A - v * w' - w * v' -* - CALL DSYR2( UPLO, N-I, -ONE, A( I+1, I ), 1, TAU( I ), 1, - $ A( I+1, I+1 ), LDA ) -* - A( I+1, I ) = E( I ) - END IF - D( I ) = A( I, I ) - TAU( I ) = TAUI - 20 CONTINUE - D( N ) = A( N, N ) - END IF -* - RETURN -* -* End of DSYTD2 -* - END |