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Diffstat (limited to 'src/lib/blas/dtbsv.f')
| -rw-r--r-- | src/lib/blas/dtbsv.f | 346 |
1 files changed, 0 insertions, 346 deletions
diff --git a/src/lib/blas/dtbsv.f b/src/lib/blas/dtbsv.f deleted file mode 100644 index d87ed82d..00000000 --- a/src/lib/blas/dtbsv.f +++ /dev/null @@ -1,346 +0,0 @@ - SUBROUTINE DTBSV ( UPLO, TRANS, DIAG, N, K, A, LDA, X, INCX ) -* .. Scalar Arguments .. - INTEGER INCX, K, LDA, N - CHARACTER*1 DIAG, TRANS, UPLO -* .. Array Arguments .. - DOUBLE PRECISION A( LDA, * ), X( * ) -* .. -* -* Purpose -* ======= -* -* DTBSV solves one of the systems of equations -* -* A*x = b, or A'*x = b, -* -* where b and x are n element vectors and A is an n by n unit, or -* non-unit, upper or lower triangular band matrix, with ( k + 1 ) -* diagonals. -* -* No test for singularity or near-singularity is included in this -* routine. Such tests must be performed before calling this routine. -* -* Parameters -* ========== -* -* UPLO - CHARACTER*1. -* On entry, UPLO specifies whether the matrix is an upper or -* lower triangular matrix as follows: -* -* UPLO = 'U' or 'u' A is an upper triangular matrix. -* -* UPLO = 'L' or 'l' A is a lower triangular matrix. -* -* Unchanged on exit. -* -* TRANS - CHARACTER*1. -* On entry, TRANS specifies the equations to be solved as -* follows: -* -* TRANS = 'N' or 'n' A*x = b. -* -* TRANS = 'T' or 't' A'*x = b. -* -* TRANS = 'C' or 'c' A'*x = b. -* -* Unchanged on exit. -* -* DIAG - CHARACTER*1. -* On entry, DIAG specifies whether or not A is unit -* triangular as follows: -* -* DIAG = 'U' or 'u' A is assumed to be unit triangular. -* -* DIAG = 'N' or 'n' A is not assumed to be unit -* triangular. -* -* Unchanged on exit. -* -* N - INTEGER. -* On entry, N specifies the order of the matrix A. -* N must be at least zero. -* Unchanged on exit. -* -* K - INTEGER. -* On entry with UPLO = 'U' or 'u', K specifies the number of -* super-diagonals of the matrix A. -* On entry with UPLO = 'L' or 'l', K specifies the number of -* sub-diagonals of the matrix A. -* K must satisfy 0 .le. K. -* Unchanged on exit. -* -* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). -* Before entry with UPLO = 'U' or 'u', the leading ( k + 1 ) -* by n part of the array A must contain the upper triangular -* band part of the matrix of coefficients, supplied column by -* column, with the leading diagonal of the matrix in row -* ( k + 1 ) of the array, the first super-diagonal starting at -* position 2 in row k, and so on. The top left k by k triangle -* of the array A is not referenced. -* The following program segment will transfer an upper -* triangular band matrix from conventional full matrix storage -* to band storage: -* -* DO 20, J = 1, N -* M = K + 1 - J -* DO 10, I = MAX( 1, J - K ), J -* A( M + I, J ) = matrix( I, J ) -* 10 CONTINUE -* 20 CONTINUE -* -* Before entry with UPLO = 'L' or 'l', the leading ( k + 1 ) -* by n part of the array A must contain the lower triangular -* band part of the matrix of coefficients, supplied column by -* column, with the leading diagonal of the matrix in row 1 of -* the array, the first sub-diagonal starting at position 1 in -* row 2, and so on. The bottom right k by k triangle of the -* array A is not referenced. -* The following program segment will transfer a lower -* triangular band matrix from conventional full matrix storage -* to band storage: -* -* DO 20, J = 1, N -* M = 1 - J -* DO 10, I = J, MIN( N, J + K ) -* A( M + I, J ) = matrix( I, J ) -* 10 CONTINUE -* 20 CONTINUE -* -* Note that when DIAG = 'U' or 'u' the elements of the array A -* corresponding to the diagonal elements of the matrix are not -* referenced, but are assumed to be unity. -* Unchanged on exit. -* -* LDA - INTEGER. -* On entry, LDA specifies the first dimension of A as declared -* in the calling (sub) program. LDA must be at least -* ( k + 1 ). -* Unchanged on exit. -* -* X - DOUBLE PRECISION array of dimension at least -* ( 1 + ( n - 1 )*abs( INCX ) ). -* Before entry, the incremented array X must contain the n -* element right-hand side vector b. On exit, X is overwritten -* with the solution vector x. -* -* INCX - INTEGER. -* On entry, INCX specifies the increment for the elements of -* X. INCX must not be zero. -* Unchanged on exit. -* -* -* Level 2 Blas routine. -* -* -- Written on 22-October-1986. -* Jack Dongarra, Argonne National Lab. -* Jeremy Du Croz, Nag Central Office. -* Sven Hammarling, Nag Central Office. -* Richard Hanson, Sandia National Labs. -* -* -* .. Parameters .. - DOUBLE PRECISION ZERO - PARAMETER ( ZERO = 0.0D+0 ) -* .. Local Scalars .. - DOUBLE PRECISION TEMP - INTEGER I, INFO, IX, J, JX, KPLUS1, KX, L - LOGICAL NOUNIT -* .. External Functions .. - LOGICAL LSAME - EXTERNAL LSAME -* .. External Subroutines .. - EXTERNAL XERBLA -* .. Intrinsic Functions .. - INTRINSIC MAX, MIN -* .. -* .. Executable Statements .. -* -* Test the input parameters. -* - INFO = 0 - IF ( .NOT.LSAME( UPLO , 'U' ).AND. - $ .NOT.LSAME( UPLO , 'L' ) )THEN - INFO = 1 - ELSE IF( .NOT.LSAME( TRANS, 'N' ).AND. - $ .NOT.LSAME( TRANS, 'T' ).AND. - $ .NOT.LSAME( TRANS, 'C' ) )THEN - INFO = 2 - ELSE IF( .NOT.LSAME( DIAG , 'U' ).AND. - $ .NOT.LSAME( DIAG , 'N' ) )THEN - INFO = 3 - ELSE IF( N.LT.0 )THEN - INFO = 4 - ELSE IF( K.LT.0 )THEN - INFO = 5 - ELSE IF( LDA.LT.( K + 1 ) )THEN - INFO = 7 - ELSE IF( INCX.EQ.0 )THEN - INFO = 9 - END IF - IF( INFO.NE.0 )THEN - CALL XERBLA( 'DTBSV ', INFO ) - RETURN - END IF -* -* Quick return if possible. -* - IF( N.EQ.0 ) - $ RETURN -* - NOUNIT = LSAME( DIAG, 'N' ) -* -* Set up the start point in X if the increment is not unity. This -* will be ( N - 1 )*INCX too small for descending loops. -* - IF( INCX.LE.0 )THEN - KX = 1 - ( N - 1 )*INCX - ELSE IF( INCX.NE.1 )THEN - KX = 1 - END IF -* -* Start the operations. In this version the elements of A are -* accessed by sequentially with one pass through A. -* - IF( LSAME( TRANS, 'N' ) )THEN -* -* Form x := inv( A )*x. -* - IF( LSAME( UPLO, 'U' ) )THEN - KPLUS1 = K + 1 - IF( INCX.EQ.1 )THEN - DO 20, J = N, 1, -1 - IF( X( J ).NE.ZERO )THEN - L = KPLUS1 - J - IF( NOUNIT ) - $ X( J ) = X( J )/A( KPLUS1, J ) - TEMP = X( J ) - DO 10, I = J - 1, MAX( 1, J - K ), -1 - X( I ) = X( I ) - TEMP*A( L + I, J ) - 10 CONTINUE - END IF - 20 CONTINUE - ELSE - KX = KX + ( N - 1 )*INCX - JX = KX - DO 40, J = N, 1, -1 - KX = KX - INCX - IF( X( JX ).NE.ZERO )THEN - IX = KX - L = KPLUS1 - J - IF( NOUNIT ) - $ X( JX ) = X( JX )/A( KPLUS1, J ) - TEMP = X( JX ) - DO 30, I = J - 1, MAX( 1, J - K ), -1 - X( IX ) = X( IX ) - TEMP*A( L + I, J ) - IX = IX - INCX - 30 CONTINUE - END IF - JX = JX - INCX - 40 CONTINUE - END IF - ELSE - IF( INCX.EQ.1 )THEN - DO 60, J = 1, N - IF( X( J ).NE.ZERO )THEN - L = 1 - J - IF( NOUNIT ) - $ X( J ) = X( J )/A( 1, J ) - TEMP = X( J ) - DO 50, I = J + 1, MIN( N, J + K ) - X( I ) = X( I ) - TEMP*A( L + I, J ) - 50 CONTINUE - END IF - 60 CONTINUE - ELSE - JX = KX - DO 80, J = 1, N - KX = KX + INCX - IF( X( JX ).NE.ZERO )THEN - IX = KX - L = 1 - J - IF( NOUNIT ) - $ X( JX ) = X( JX )/A( 1, J ) - TEMP = X( JX ) - DO 70, I = J + 1, MIN( N, J + K ) - X( IX ) = X( IX ) - TEMP*A( L + I, J ) - IX = IX + INCX - 70 CONTINUE - END IF - JX = JX + INCX - 80 CONTINUE - END IF - END IF - ELSE -* -* Form x := inv( A')*x. -* - IF( LSAME( UPLO, 'U' ) )THEN - KPLUS1 = K + 1 - IF( INCX.EQ.1 )THEN - DO 100, J = 1, N - TEMP = X( J ) - L = KPLUS1 - J - DO 90, I = MAX( 1, J - K ), J - 1 - TEMP = TEMP - A( L + I, J )*X( I ) - 90 CONTINUE - IF( NOUNIT ) - $ TEMP = TEMP/A( KPLUS1, J ) - X( J ) = TEMP - 100 CONTINUE - ELSE - JX = KX - DO 120, J = 1, N - TEMP = X( JX ) - IX = KX - L = KPLUS1 - J - DO 110, I = MAX( 1, J - K ), J - 1 - TEMP = TEMP - A( L + I, J )*X( IX ) - IX = IX + INCX - 110 CONTINUE - IF( NOUNIT ) - $ TEMP = TEMP/A( KPLUS1, J ) - X( JX ) = TEMP - JX = JX + INCX - IF( J.GT.K ) - $ KX = KX + INCX - 120 CONTINUE - END IF - ELSE - IF( INCX.EQ.1 )THEN - DO 140, J = N, 1, -1 - TEMP = X( J ) - L = 1 - J - DO 130, I = MIN( N, J + K ), J + 1, -1 - TEMP = TEMP - A( L + I, J )*X( I ) - 130 CONTINUE - IF( NOUNIT ) - $ TEMP = TEMP/A( 1, J ) - X( J ) = TEMP - 140 CONTINUE - ELSE - KX = KX + ( N - 1 )*INCX - JX = KX - DO 160, J = N, 1, -1 - TEMP = X( JX ) - IX = KX - L = 1 - J - DO 150, I = MIN( N, J + K ), J + 1, -1 - TEMP = TEMP - A( L + I, J )*X( IX ) - IX = IX - INCX - 150 CONTINUE - IF( NOUNIT ) - $ TEMP = TEMP/A( 1, J ) - X( JX ) = TEMP - JX = JX - INCX - IF( ( N - J ).GE.K ) - $ KX = KX - INCX - 160 CONTINUE - END IF - END IF - END IF -* - RETURN -* -* End of DTBSV . -* - END |