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authorjulie <julielangou@users.noreply.github.com>2010-11-03 17:55:43 +0000
committerjulie <julielangou@users.noreply.github.com>2010-11-03 17:55:43 +0000
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tree0e69ae0e4dfbf4b996ea77393e78d445d2d05b2f /SRC/ssytri2x.f
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Commiting the 3 other precisions (single, complex, dcomplex) for sytri using Level BLAS 3.
Update testing accordingly
Diffstat (limited to 'SRC/ssytri2x.f')
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diff --git a/SRC/ssytri2x.f b/SRC/ssytri2x.f
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+ SUBROUTINE SSYTRI2X( UPLO, N, A, LDA, IPIV, WORK, NB, INFO )
+*
+* -- LAPACK routine (version 3.3.0) --
+* -- LAPACK is a software package provided by Univ. of Tennessee, --
+* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+* November 2010
+*
+* -- Written by Julie Langou of the Univ. of TN --
+*
+* .. Scalar Arguments ..
+ CHARACTER UPLO
+ INTEGER INFO, LDA, N, NB
+* ..
+* .. Array Arguments ..
+ INTEGER IPIV( * )
+ REAL A( LDA, * ), WORK( N+NB+1,* )
+* ..
+*
+* Purpose
+* =======
+*
+* SSYTRI2X computes the inverse of a real symmetric indefinite matrix
+* A using the factorization A = U*D*U**T or A = L*D*L**T computed by
+* SSYTRF.
+*
+* Arguments
+* =========
+*
+* UPLO (input) CHARACTER*1
+* Specifies whether the details of the factorization are stored
+* as an upper or lower triangular matrix.
+* = 'U': Upper triangular, form is A = U*D*U**T;
+* = 'L': Lower triangular, form is A = L*D*L**T.
+*
+* N (input) INTEGER
+* The order of the matrix A. N >= 0.
+*
+* A (input/output) REAL array, dimension (LDA,N)
+* On entry, the NNB diagonal matrix D and the multipliers
+* used to obtain the factor U or L as computed by SSYTRF.
+*
+* On exit, if INFO = 0, the (symmetric) inverse of the original
+* matrix. If UPLO = 'U', the upper triangular part of the
+* inverse is formed and the part of A below the diagonal is not
+* referenced; if UPLO = 'L' the lower triangular part of the
+* inverse is formed and the part of A above the diagonal is
+* not referenced.
+*
+* LDA (input) INTEGER
+* The leading dimension of the array A. LDA >= max(1,N).
+*
+* IPIV (input) INTEGER array, dimension (N)
+* Details of the interchanges and the NNB structure of D
+* as determined by SSYTRF.
+*
+* WORK (workspace) REAL array, dimension (N+NNB+1,NNB+3)
+*
+* NB (input) INTEGER
+* Block size
+*
+* INFO (output) INTEGER
+* = 0: successful exit
+* < 0: if INFO = -i, the i-th argument had an illegal value
+* > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
+* inverse could not be computed.
+*
+* =====================================================================
+*
+* .. Parameters ..
+ REAL ONE, ZERO
+ PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
+* ..
+* .. Local Scalars ..
+ LOGICAL UPPER
+ INTEGER I, IINFO, IP, K, CUT, NNB
+ INTEGER COUNT
+ INTEGER J, U11, INVD
+
+ REAL AK, AKKP1, AKP1, D, T
+ REAL U01_I_J, U01_IP1_J
+ REAL U11_I_J, U11_IP1_J
+* ..
+* .. External Functions ..
+ LOGICAL LSAME
+ EXTERNAL LSAME
+* ..
+* .. External Subroutines ..
+ EXTERNAL SSYSCONV, XERBLA, STRTRI
+ EXTERNAL SGEMM, STRMM, SSYSWAPR
+* ..
+* .. Intrinsic Functions ..
+ INTRINSIC MAX
+* ..
+* .. 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
+*
+* Quick return if possible
+*
+*
+ IF( INFO.NE.0 ) THEN
+ CALL XERBLA( 'SSYTRI2X', -INFO )
+ RETURN
+ END IF
+ IF( N.EQ.0 )
+ $ RETURN
+*
+* Convert A
+* Workspace got Non-diag elements of D
+*
+ CALL SSYCONV( UPLO, 'C', N, A, LDA, IPIV, WORK, IINFO )
+*
+* Check that the diagonal matrix D is nonsingular.
+*
+ IF( UPPER ) THEN
+*
+* Upper triangular storage: examine D from bottom to top
+*
+ DO INFO = N, 1, -1
+ IF( IPIV( INFO ).GT.0 .AND. A( INFO, INFO ).EQ.ZERO )
+ $ RETURN
+ END DO
+ ELSE
+*
+* Lower triangular storage: examine D from top to bottom.
+*
+ DO INFO = 1, N
+ IF( IPIV( INFO ).GT.0 .AND. A( INFO, INFO ).EQ.ZERO )
+ $ RETURN
+ END DO
+ END IF
+ INFO = 0
+*
+* Splitting Workspace
+* U01 is a block (N,NB+1)
+* The first element of U01 is in WORK(1,1)
+* U11 is a block (NB+1,NB+1)
+* The first element of U11 is in WORK(N+1,1)
+ U11 = N
+* INVD is a block (N,2)
+* The first element of INVD is in WORK(1,INVD)
+ INVD = NB+2
+
+ IF( UPPER ) THEN
+*
+* invA = P * inv(U')*inv(D)*inv(U)*P'.
+*
+ CALL STRTRI( UPLO, 'U', N, A, LDA, INFO )
+*
+* inv(D) and inv(D)*inv(U)
+*
+ K=1
+ DO WHILE ( K .LE. N )
+ IF( IPIV( K ).GT.0 ) THEN
+* 1 x 1 diagonal NNB
+ WORK(K,INVD) = 1/ A( K, K )
+ WORK(K,INVD+1) = 0
+ K=K+1
+ ELSE
+* 2 x 2 diagonal NNB
+ T = WORK(K+1,1)
+ AK = A( K, K ) / T
+ AKP1 = A( K+1, K+1 ) / T
+ AKKP1 = WORK(K+1,1) / T
+ D = T*( AK*AKP1-ONE )
+ WORK(K,INVD) = AKP1 / D
+ WORK(K+1,INVD+1) = AK / D
+ WORK(K,INVD+1) = -AKKP1 / D
+ WORK(K+1,INVD) = -AKKP1 / D
+ K=K+2
+ END IF
+ END DO
+*
+* inv(U') = (inv(U))'
+*
+* inv(U')*inv(D)*inv(U)
+*
+ CUT=N
+ DO WHILE (CUT .GT. 0)
+ NNB=NB
+ IF (CUT .LE. NNB) THEN
+ NNB=CUT
+ ELSE
+ COUNT = 0
+* count negative elements,
+ DO I=CUT+1-NNB,CUT
+ IF (IPIV(I) .LT. 0) COUNT=COUNT+1
+ END DO
+* need a even number for a clear cut
+ IF (MOD(COUNT,2) .EQ. 1) NNB=NNB+1
+ END IF
+
+ CUT=CUT-NNB
+*
+* U01 Block
+*
+ DO I=1,CUT
+ DO J=1,NNB
+ WORK(I,J)=A(I,CUT+J)
+ END DO
+ END DO
+*
+* U11 Block
+*
+ DO I=1,NNB
+ WORK(U11+I,I)=ONE
+ DO J=1,I-1
+ WORK(U11+I,J)=ZERO
+ END DO
+ DO J=I+1,NNB
+ WORK(U11+I,J)=A(CUT+I,CUT+J)
+ END DO
+ END DO
+*
+* invD*U01
+*
+ I=1
+ DO WHILE (I .LE. CUT)
+ IF (IPIV(I) > 0) THEN
+ DO J=1,NNB
+ WORK(I,J)=WORK(I,INVD)*WORK(I,J)
+ END DO
+ I=I+1
+ ELSE
+ DO J=1,NNB
+ U01_I_J = WORK(I,J)
+ U01_IP1_J = WORK(I+1,J)
+ WORK(I,J)=WORK(I,INVD)*U01_I_J+
+ $ WORK(I,INVD+1)*U01_IP1_J
+ WORK(I+1,J)=WORK(I+1,INVD)*U01_I_J+
+ $ WORK(I+1,INVD+1)*U01_IP1_J
+ END DO
+ I=I+2
+ END IF
+ END DO
+*
+* invD1*U11
+*
+ I=1
+ DO WHILE (I .LE. NNB)
+ IF (IPIV(CUT+I) > 0) THEN
+ DO J=I,NNB
+ WORK(U11+I,J)=WORK(CUT+I,INVD)*WORK(U11+I,J)
+ END DO
+ I=I+1
+ ELSE
+ DO J=I,NNB
+ U11_I_J = WORK(U11+I,J)
+ U11_IP1_J = WORK(U11+I+1,J)
+ WORK(U11+I,J)=WORK(CUT+I,INVD)*WORK(U11+I,J) +
+ $ WORK(CUT+I,INVD+1)*WORK(U11+I+1,J)
+ WORK(U11+I+1,J)=WORK(CUT+I+1,INVD)*U11_I_J+
+ $ WORK(CUT+I+1,INVD+1)*U11_IP1_J
+ END DO
+ I=I+2
+ END IF
+ END DO
+*
+* U11T*invD1*U11->U11
+*
+ CALL STRMM('L','U','T','U',NNB, NNB,
+ $ ONE,A(CUT+1,CUT+1),LDA,WORK(U11+1,1),N+NB+1)
+*
+* U01'invD*U01->A(CUT+I,CUT+J)
+*
+ CALL SGEMM('T','N',NNB,NNB,CUT,ONE,A(1,CUT+1),LDA,
+ $ WORK,N+NB+1, ZERO, A(CUT+1,CUT+1), LDA)
+*
+* U11 = U11T*invD1*U11 + U01'invD*U01 (Prem + Deus)
+*
+ DO I=1,NNB
+ DO J=I,NNB
+ A(CUT+I,CUT+J)=A(CUT+I,CUT+J)+WORK(U11+I,J)
+ END DO
+ END DO
+*
+* U01 = U00T*invD0*U01
+*
+ CALL STRMM('L',UPLO,'T','U',CUT, NNB,
+ $ ONE,A,LDA,WORK,N+NB+1)
+
+*
+* Update U01
+*
+ DO I=1,CUT
+ DO J=1,NNB
+ A(I,CUT+J)=WORK(I,J)
+ END DO
+ END DO
+* Next Block
+ END DO
+*
+* Apply PERMUTATIONS P and P': P * inv(U')*inv(D)*inv(U) *P'
+*
+ I=1
+ DO WHILE ( I .LE. N )
+ IF( IPIV(I) .GT. 0 ) THEN
+ IP=IPIV(I)
+ IF (I .LT. IP) CALL SSYSWAPR( UPLO, N, A, I ,IP )
+ IF (I .GT. IP) CALL SSYSWAPR( UPLO, N, A, IP ,I )
+ ELSE
+ IP=-IPIV(I)
+ I=I+1
+ IF ( (I-1) .LT. IP)
+ $ CALL SSYSWAPR( UPLO, N, A, I-1 ,IP )
+ IF ( (I-1) .GT. IP)
+ $ CALL SSYSWAPR( UPLO, N, A, IP ,I-1 )
+ ENDIF
+ I=I+1
+ END DO
+
+ DO I=1,N
+ DO J=I+1,N
+ A(J,I)=A(I,J)
+ END DO
+ END DO
+ ELSE
+*
+* LOWER...
+*
+* invA = P * inv(U')*inv(D)*inv(U)*P'.
+*
+ CALL STRTRI( UPLO, 'U', N, A, LDA, INFO )
+*
+* inv(D) and inv(D)*inv(U)
+*
+ K=N
+ DO WHILE ( K .GE. 1 )
+ IF( IPIV( K ).GT.0 ) THEN
+* 1 x 1 diagonal NNB
+ WORK(K,INVD) = 1/ A( K, K )
+ WORK(K,INVD+1) = 0
+ K=K-1
+ ELSE
+* 2 x 2 diagonal NNB
+ T = WORK(K-1,1)
+ AK = A( K-1, K-1 ) / T
+ AKP1 = A( K, K ) / T
+ AKKP1 = WORK(K-1,1) / T
+ D = T*( AK*AKP1-ONE )
+ WORK(K-1,INVD) = AKP1 / D
+ WORK(K,INVD) = AK / D
+ WORK(K,INVD+1) = -AKKP1 / D
+ WORK(K-1,INVD+1) = -AKKP1 / D
+ K=K-2
+ END IF
+ END DO
+*
+* inv(U') = (inv(U))'
+*
+* inv(U')*inv(D)*inv(U)
+*
+ CUT=0
+ DO WHILE (CUT .LT. N)
+ NNB=NB
+ IF (CUT + NNB .GE. N) THEN
+ NNB=N-CUT
+ ELSE
+ COUNT = 0
+* count negative elements,
+ DO I=CUT+1,CUT+NNB
+ IF (IPIV(I) .LT. 0) COUNT=COUNT+1
+ END DO
+* need a even number for a clear cut
+ IF (MOD(COUNT,2) .EQ. 1) NNB=NNB+1
+ END IF
+* L21 Block
+ DO I=1,N-CUT-NNB
+ DO J=1,NNB
+ WORK(I,J)=A(CUT+NNB+I,CUT+J)
+ END DO
+ END DO
+* L11 Block
+ DO I=1,NNB
+ WORK(U11+I,I)=ONE
+ DO J=I+1,NNB
+ WORK(U11+I,J)=ZERO
+ END DO
+ DO J=1,I-1
+ WORK(U11+I,J)=A(CUT+I,CUT+J)
+ END DO
+ END DO
+*
+* invD*L21
+*
+ I=N-CUT-NNB
+ DO WHILE (I .GE. 1)
+ IF (IPIV(CUT+NNB+I) > 0) THEN
+ DO J=1,NNB
+ WORK(I,J)=WORK(CUT+NNB+I,INVD)*WORK(I,J)
+ END DO
+ I=I-1
+ ELSE
+ DO J=1,NNB
+ U01_I_J = WORK(I,J)
+ U01_IP1_J = WORK(I-1,J)
+ WORK(I,J)=WORK(CUT+NNB+I,INVD)*U01_I_J+
+ $ WORK(CUT+NNB+I,INVD+1)*U01_IP1_J
+ WORK(I-1,J)=WORK(CUT+NNB+I-1,INVD+1)*U01_I_J+
+ $ WORK(CUT+NNB+I-1,INVD)*U01_IP1_J
+ END DO
+ I=I-2
+ END IF
+ END DO
+*
+* invD1*L11
+*
+ I=NNB
+ DO WHILE (I .GE. 1)
+ IF (IPIV(CUT+I) > 0) THEN
+ DO J=1,NNB
+ WORK(U11+I,J)=WORK(CUT+I,INVD)*WORK(U11+I,J)
+ END DO
+ I=I-1
+ ELSE
+ DO J=1,NNB
+ U11_I_J = WORK(U11+I,J)
+ U11_IP1_J = WORK(U11+I-1,J)
+ WORK(U11+I,J)=WORK(CUT+I,INVD)*WORK(U11+I,J) +
+ $ WORK(CUT+I,INVD+1)*U11_IP1_J
+ WORK(U11+I-1,J)=WORK(CUT+I-1,INVD+1)*U11_I_J+
+ $ WORK(CUT+I-1,INVD)*U11_IP1_J
+ END DO
+ I=I-2
+ END IF
+ END DO
+*
+* U11T*invD1*U11->U11
+*
+ CALL STRMM('L',UPLO,'T','U',NNB, NNB,
+ $ ONE,A(CUT+1,CUT+1),LDA,WORK(U11+1,1),N+NB+1)
+*
+* L21T*invD2*L21->A(CUT+I,CUT+J)
+*
+ CALL SGEMM('T','N',NNB,NNB,N-NNB-CUT,ONE,A(CUT+NNB+1,CUT+1)
+ $ ,LDA,WORK,N+NB+1, ZERO, A(CUT+1,CUT+1), LDA)
+
+*
+* L11 = L11T*invD1*L11 + U01'invD*U01 (Prem + Deus)
+*
+ DO I=1,NNB
+ DO J=1,I
+ A(CUT+I,CUT+J)=A(CUT+I,CUT+J)+WORK(U11+I,J)
+ END DO
+ END DO
+*
+* U01 = L22T*invD2*L21
+*
+ CALL STRMM('L',UPLO,'T','U', N-NNB-CUT, NNB,
+ $ ONE,A(CUT+NNB+1,CUT+NNB+1),LDA,WORK,N+NB+1)
+
+* Update L21
+ DO I=1,N-CUT-NNB
+ DO J=1,NNB
+ A(CUT+NNB+I,CUT+J)=WORK(I,J)
+ END DO
+ END DO
+* Next Block
+ CUT=CUT+NNB
+ END DO
+*
+* Apply PERMUTATIONS P and P': P * inv(U')*inv(D)*inv(U) *P'
+*
+ I=N
+ DO WHILE ( I .GE. 1 )
+ IF( IPIV(I) .GT. 0 ) THEN
+ IP=IPIV(I)
+ IF (I .LT. IP) CALL SSYSWAPR( UPLO, N, A, I ,IP )
+ IF (I .GT. IP) CALL SSYSWAPR( UPLO, N, A, IP ,I )
+ ELSE
+ IP=-IPIV(I)
+ IF ( I .LT. IP) CALL SSYSWAPR( UPLO, N, A, I ,IP )
+ IF ( I .GT. IP) CALL SSYSWAPR( UPLO, N, A, IP ,I )
+ I=I-1
+ ENDIF
+ I=I-1
+ END DO
+ END IF
+*
+ RETURN
+*
+* End of SSYTRI2X
+*
+ END
+