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Diffstat (limited to '2.3-1/src/fortran/lapack/dgelsx.f')
| -rw-r--r-- | 2.3-1/src/fortran/lapack/dgelsx.f | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/2.3-1/src/fortran/lapack/dgelsx.f b/2.3-1/src/fortran/lapack/dgelsx.f new file mode 100644 index 00000000..a597cd47 --- /dev/null +++ b/2.3-1/src/fortran/lapack/dgelsx.f @@ -0,0 +1,349 @@ + SUBROUTINE DGELSX( M, N, NRHS, A, LDA, B, LDB, JPVT, RCOND, RANK, + $ WORK, INFO ) +* +* -- LAPACK driver routine (version 3.1) -- +* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. +* November 2006 +* +* .. Scalar Arguments .. + INTEGER INFO, LDA, LDB, M, N, NRHS, RANK + DOUBLE PRECISION RCOND +* .. +* .. Array Arguments .. + INTEGER JPVT( * ) + DOUBLE PRECISION A( LDA, * ), B( LDB, * ), WORK( * ) +* .. +* +* Purpose +* ======= +* +* This routine is deprecated and has been replaced by routine DGELSY. +* +* DGELSX computes the minimum-norm solution to a real linear least +* squares problem: +* minimize || A * X - B || +* using a complete orthogonal factorization of A. A is an M-by-N +* matrix which may be rank-deficient. +* +* Several right hand side vectors b and solution vectors x can be +* handled in a single call; they are stored as the columns of the +* M-by-NRHS right hand side matrix B and the N-by-NRHS solution +* matrix X. +* +* The routine first computes a QR factorization with column pivoting: +* A * P = Q * [ R11 R12 ] +* [ 0 R22 ] +* with R11 defined as the largest leading submatrix whose estimated +* condition number is less than 1/RCOND. The order of R11, RANK, +* is the effective rank of A. +* +* Then, R22 is considered to be negligible, and R12 is annihilated +* by orthogonal transformations from the right, arriving at the +* complete orthogonal factorization: +* A * P = Q * [ T11 0 ] * Z +* [ 0 0 ] +* The minimum-norm solution is then +* X = P * Z' [ inv(T11)*Q1'*B ] +* [ 0 ] +* where Q1 consists of the first RANK columns of Q. +* +* Arguments +* ========= +* +* M (input) INTEGER +* The number of rows of the matrix A. M >= 0. +* +* N (input) INTEGER +* The number of columns of the matrix A. N >= 0. +* +* NRHS (input) INTEGER +* The number of right hand sides, i.e., the number of +* columns of matrices B and X. NRHS >= 0. +* +* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) +* On entry, the M-by-N matrix A. +* On exit, A has been overwritten by details of its +* complete orthogonal factorization. +* +* LDA (input) INTEGER +* The leading dimension of the array A. LDA >= max(1,M). +* +* B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS) +* On entry, the M-by-NRHS right hand side matrix B. +* On exit, the N-by-NRHS solution matrix X. +* If m >= n and RANK = n, the residual sum-of-squares for +* the solution in the i-th column is given by the sum of +* squares of elements N+1:M in that column. +* +* LDB (input) INTEGER +* The leading dimension of the array B. LDB >= max(1,M,N). +* +* JPVT (input/output) INTEGER array, dimension (N) +* On entry, if JPVT(i) .ne. 0, the i-th column of A is an +* initial column, otherwise it is a free column. Before +* the QR factorization of A, all initial columns are +* permuted to the leading positions; only the remaining +* free columns are moved as a result of column pivoting +* during the factorization. +* On exit, if JPVT(i) = k, then the i-th column of A*P +* was the k-th column of A. +* +* RCOND (input) DOUBLE PRECISION +* RCOND is used to determine the effective rank of A, which +* is defined as the order of the largest leading triangular +* submatrix R11 in the QR factorization with pivoting of A, +* whose estimated condition number < 1/RCOND. +* +* RANK (output) INTEGER +* The effective rank of A, i.e., the order of the submatrix +* R11. This is the same as the order of the submatrix T11 +* in the complete orthogonal factorization of A. +* +* WORK (workspace) DOUBLE PRECISION array, dimension +* (max( min(M,N)+3*N, 2*min(M,N)+NRHS )), +* +* INFO (output) INTEGER +* = 0: successful exit +* < 0: if INFO = -i, the i-th argument had an illegal value +* +* ===================================================================== +* +* .. Parameters .. + INTEGER IMAX, IMIN + PARAMETER ( IMAX = 1, IMIN = 2 ) + DOUBLE PRECISION ZERO, ONE, DONE, NTDONE + PARAMETER ( ZERO = 0.0D0, ONE = 1.0D0, DONE = ZERO, + $ NTDONE = ONE ) +* .. +* .. Local Scalars .. + INTEGER I, IASCL, IBSCL, ISMAX, ISMIN, J, K, MN + DOUBLE PRECISION ANRM, BIGNUM, BNRM, C1, C2, S1, S2, SMAX, + $ SMAXPR, SMIN, SMINPR, SMLNUM, T1, T2 +* .. +* .. External Functions .. + DOUBLE PRECISION DLAMCH, DLANGE + EXTERNAL DLAMCH, DLANGE +* .. +* .. External Subroutines .. + EXTERNAL DGEQPF, DLAIC1, DLASCL, DLASET, DLATZM, DORM2R, + $ DTRSM, DTZRQF, XERBLA +* .. +* .. Intrinsic Functions .. + INTRINSIC ABS, MAX, MIN +* .. +* .. Executable Statements .. +* + MN = MIN( M, N ) + ISMIN = MN + 1 + ISMAX = 2*MN + 1 +* +* Test the input arguments. +* + INFO = 0 + IF( M.LT.0 ) THEN + INFO = -1 + ELSE IF( N.LT.0 ) THEN + INFO = -2 + ELSE IF( NRHS.LT.0 ) THEN + INFO = -3 + ELSE IF( LDA.LT.MAX( 1, M ) ) THEN + INFO = -5 + ELSE IF( LDB.LT.MAX( 1, M, N ) ) THEN + INFO = -7 + END IF +* + IF( INFO.NE.0 ) THEN + CALL XERBLA( 'DGELSX', -INFO ) + RETURN + END IF +* +* Quick return if possible +* + IF( MIN( M, N, NRHS ).EQ.0 ) THEN + RANK = 0 + RETURN + END IF +* +* Get machine parameters +* + SMLNUM = DLAMCH( 'S' ) / DLAMCH( 'P' ) + BIGNUM = ONE / SMLNUM + CALL DLABAD( SMLNUM, BIGNUM ) +* +* Scale A, B if max elements outside range [SMLNUM,BIGNUM] +* + ANRM = DLANGE( 'M', M, N, A, LDA, WORK ) + IASCL = 0 + IF( ANRM.GT.ZERO .AND. ANRM.LT.SMLNUM ) THEN +* +* Scale matrix norm up to SMLNUM +* + CALL DLASCL( 'G', 0, 0, ANRM, SMLNUM, M, N, A, LDA, INFO ) + IASCL = 1 + ELSE IF( ANRM.GT.BIGNUM ) THEN +* +* Scale matrix norm down to BIGNUM +* + CALL DLASCL( 'G', 0, 0, ANRM, BIGNUM, M, N, A, LDA, INFO ) + IASCL = 2 + ELSE IF( ANRM.EQ.ZERO ) THEN +* +* Matrix all zero. Return zero solution. +* + CALL DLASET( 'F', MAX( M, N ), NRHS, ZERO, ZERO, B, LDB ) + RANK = 0 + GO TO 100 + END IF +* + BNRM = DLANGE( 'M', M, NRHS, B, LDB, WORK ) + IBSCL = 0 + IF( BNRM.GT.ZERO .AND. BNRM.LT.SMLNUM ) THEN +* +* Scale matrix norm up to SMLNUM +* + CALL DLASCL( 'G', 0, 0, BNRM, SMLNUM, M, NRHS, B, LDB, INFO ) + IBSCL = 1 + ELSE IF( BNRM.GT.BIGNUM ) THEN +* +* Scale matrix norm down to BIGNUM +* + CALL DLASCL( 'G', 0, 0, BNRM, BIGNUM, M, NRHS, B, LDB, INFO ) + IBSCL = 2 + END IF +* +* Compute QR factorization with column pivoting of A: +* A * P = Q * R +* + CALL DGEQPF( M, N, A, LDA, JPVT, WORK( 1 ), WORK( MN+1 ), INFO ) +* +* workspace 3*N. Details of Householder rotations stored +* in WORK(1:MN). +* +* Determine RANK using incremental condition estimation +* + WORK( ISMIN ) = ONE + WORK( ISMAX ) = ONE + SMAX = ABS( A( 1, 1 ) ) + SMIN = SMAX + IF( ABS( A( 1, 1 ) ).EQ.ZERO ) THEN + RANK = 0 + CALL DLASET( 'F', MAX( M, N ), NRHS, ZERO, ZERO, B, LDB ) + GO TO 100 + ELSE + RANK = 1 + END IF +* + 10 CONTINUE + IF( RANK.LT.MN ) THEN + I = RANK + 1 + CALL DLAIC1( IMIN, RANK, WORK( ISMIN ), SMIN, A( 1, I ), + $ A( I, I ), SMINPR, S1, C1 ) + CALL DLAIC1( IMAX, RANK, WORK( ISMAX ), SMAX, A( 1, I ), + $ A( I, I ), SMAXPR, S2, C2 ) +* + IF( SMAXPR*RCOND.LE.SMINPR ) THEN + DO 20 I = 1, RANK + WORK( ISMIN+I-1 ) = S1*WORK( ISMIN+I-1 ) + WORK( ISMAX+I-1 ) = S2*WORK( ISMAX+I-1 ) + 20 CONTINUE + WORK( ISMIN+RANK ) = C1 + WORK( ISMAX+RANK ) = C2 + SMIN = SMINPR + SMAX = SMAXPR + RANK = RANK + 1 + GO TO 10 + END IF + END IF +* +* Logically partition R = [ R11 R12 ] +* [ 0 R22 ] +* where R11 = R(1:RANK,1:RANK) +* +* [R11,R12] = [ T11, 0 ] * Y +* + IF( RANK.LT.N ) + $ CALL DTZRQF( RANK, N, A, LDA, WORK( MN+1 ), INFO ) +* +* Details of Householder rotations stored in WORK(MN+1:2*MN) +* +* B(1:M,1:NRHS) := Q' * B(1:M,1:NRHS) +* + CALL DORM2R( 'Left', 'Transpose', M, NRHS, MN, A, LDA, WORK( 1 ), + $ B, LDB, WORK( 2*MN+1 ), INFO ) +* +* workspace NRHS +* +* B(1:RANK,1:NRHS) := inv(T11) * B(1:RANK,1:NRHS) +* + CALL DTRSM( 'Left', 'Upper', 'No transpose', 'Non-unit', RANK, + $ NRHS, ONE, A, LDA, B, LDB ) +* + DO 40 I = RANK + 1, N + DO 30 J = 1, NRHS + B( I, J ) = ZERO + 30 CONTINUE + 40 CONTINUE +* +* B(1:N,1:NRHS) := Y' * B(1:N,1:NRHS) +* + IF( RANK.LT.N ) THEN + DO 50 I = 1, RANK + CALL DLATZM( 'Left', N-RANK+1, NRHS, A( I, RANK+1 ), LDA, + $ WORK( MN+I ), B( I, 1 ), B( RANK+1, 1 ), LDB, + $ WORK( 2*MN+1 ) ) + 50 CONTINUE + END IF +* +* workspace NRHS +* +* B(1:N,1:NRHS) := P * B(1:N,1:NRHS) +* + DO 90 J = 1, NRHS + DO 60 I = 1, N + WORK( 2*MN+I ) = NTDONE + 60 CONTINUE + DO 80 I = 1, N + IF( WORK( 2*MN+I ).EQ.NTDONE ) THEN + IF( JPVT( I ).NE.I ) THEN + K = I + T1 = B( K, J ) + T2 = B( JPVT( K ), J ) + 70 CONTINUE + B( JPVT( K ), J ) = T1 + WORK( 2*MN+K ) = DONE + T1 = T2 + K = JPVT( K ) + T2 = B( JPVT( K ), J ) + IF( JPVT( K ).NE.I ) + $ GO TO 70 + B( I, J ) = T1 + WORK( 2*MN+K ) = DONE + END IF + END IF + 80 CONTINUE + 90 CONTINUE +* +* Undo scaling +* + IF( IASCL.EQ.1 ) THEN + CALL DLASCL( 'G', 0, 0, ANRM, SMLNUM, N, NRHS, B, LDB, INFO ) + CALL DLASCL( 'U', 0, 0, SMLNUM, ANRM, RANK, RANK, A, LDA, + $ INFO ) + ELSE IF( IASCL.EQ.2 ) THEN + CALL DLASCL( 'G', 0, 0, ANRM, BIGNUM, N, NRHS, B, LDB, INFO ) + CALL DLASCL( 'U', 0, 0, BIGNUM, ANRM, RANK, RANK, A, LDA, + $ INFO ) + END IF + IF( IBSCL.EQ.1 ) THEN + CALL DLASCL( 'G', 0, 0, SMLNUM, BNRM, N, NRHS, B, LDB, INFO ) + ELSE IF( IBSCL.EQ.2 ) THEN + CALL DLASCL( 'G', 0, 0, BIGNUM, BNRM, N, NRHS, B, LDB, INFO ) + END IF +* + 100 CONTINUE +* + RETURN +* +* End of DGELSX +* + END |