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Diffstat (limited to 'src/lib/lapack/dlacn2.f')
| -rw-r--r-- | src/lib/lapack/dlacn2.f | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/src/lib/lapack/dlacn2.f b/src/lib/lapack/dlacn2.f deleted file mode 100644 index 6705d256..00000000 --- a/src/lib/lapack/dlacn2.f +++ /dev/null @@ -1,214 +0,0 @@ - SUBROUTINE DLACN2( N, V, X, ISGN, EST, KASE, ISAVE ) -* -* -- LAPACK auxiliary routine (version 3.1) -- -* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. -* November 2006 -* -* .. Scalar Arguments .. - INTEGER KASE, N - DOUBLE PRECISION EST -* .. -* .. Array Arguments .. - INTEGER ISGN( * ), ISAVE( 3 ) - DOUBLE PRECISION V( * ), X( * ) -* .. -* -* Purpose -* ======= -* -* DLACN2 estimates the 1-norm of a square, real matrix A. -* Reverse communication is used for evaluating matrix-vector products. -* -* Arguments -* ========= -* -* N (input) INTEGER -* The order of the matrix. N >= 1. -* -* V (workspace) DOUBLE PRECISION array, dimension (N) -* On the final return, V = A*W, where EST = norm(V)/norm(W) -* (W is not returned). -* -* X (input/output) DOUBLE PRECISION array, dimension (N) -* On an intermediate return, X should be overwritten by -* A * X, if KASE=1, -* A' * X, if KASE=2, -* and DLACN2 must be re-called with all the other parameters -* unchanged. -* -* ISGN (workspace) INTEGER array, dimension (N) -* -* EST (input/output) DOUBLE PRECISION -* On entry with KASE = 1 or 2 and ISAVE(1) = 3, EST should be -* unchanged from the previous call to DLACN2. -* On exit, EST is an estimate (a lower bound) for norm(A). -* -* KASE (input/output) INTEGER -* On the initial call to DLACN2, KASE should be 0. -* On an intermediate return, KASE will be 1 or 2, indicating -* whether X should be overwritten by A * X or A' * X. -* On the final return from DLACN2, KASE will again be 0. -* -* ISAVE (input/output) INTEGER array, dimension (3) -* ISAVE is used to save variables between calls to DLACN2 -* -* Further Details -* ======= ======= -* -* Contributed by Nick Higham, University of Manchester. -* Originally named SONEST, dated March 16, 1988. -* -* Reference: N.J. Higham, "FORTRAN codes for estimating the one-norm of -* a real or complex matrix, with applications to condition estimation", -* ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988. -* -* This is a thread safe version of DLACON, which uses the array ISAVE -* in place of a SAVE statement, as follows: -* -* DLACON DLACN2 -* JUMP ISAVE(1) -* J ISAVE(2) -* ITER ISAVE(3) -* -* ===================================================================== -* -* .. Parameters .. - INTEGER ITMAX - PARAMETER ( ITMAX = 5 ) - DOUBLE PRECISION ZERO, ONE, TWO - PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0, TWO = 2.0D+0 ) -* .. -* .. Local Scalars .. - INTEGER I, JLAST - DOUBLE PRECISION ALTSGN, ESTOLD, TEMP -* .. -* .. External Functions .. - INTEGER IDAMAX - DOUBLE PRECISION DASUM - EXTERNAL IDAMAX, DASUM -* .. -* .. External Subroutines .. - EXTERNAL DCOPY -* .. -* .. Intrinsic Functions .. - INTRINSIC ABS, DBLE, NINT, SIGN -* .. -* .. Executable Statements .. -* - IF( KASE.EQ.0 ) THEN - DO 10 I = 1, N - X( I ) = ONE / DBLE( N ) - 10 CONTINUE - KASE = 1 - ISAVE( 1 ) = 1 - RETURN - END IF -* - GO TO ( 20, 40, 70, 110, 140 )ISAVE( 1 ) -* -* ................ ENTRY (ISAVE( 1 ) = 1) -* FIRST ITERATION. X HAS BEEN OVERWRITTEN BY A*X. -* - 20 CONTINUE - IF( N.EQ.1 ) THEN - V( 1 ) = X( 1 ) - EST = ABS( V( 1 ) ) -* ... QUIT - GO TO 150 - END IF - EST = DASUM( N, X, 1 ) -* - DO 30 I = 1, N - X( I ) = SIGN( ONE, X( I ) ) - ISGN( I ) = NINT( X( I ) ) - 30 CONTINUE - KASE = 2 - ISAVE( 1 ) = 2 - RETURN -* -* ................ ENTRY (ISAVE( 1 ) = 2) -* FIRST ITERATION. X HAS BEEN OVERWRITTEN BY TRANSPOSE(A)*X. -* - 40 CONTINUE - ISAVE( 2 ) = IDAMAX( N, X, 1 ) - ISAVE( 3 ) = 2 -* -* MAIN LOOP - ITERATIONS 2,3,...,ITMAX. -* - 50 CONTINUE - DO 60 I = 1, N - X( I ) = ZERO - 60 CONTINUE - X( ISAVE( 2 ) ) = ONE - KASE = 1 - ISAVE( 1 ) = 3 - RETURN -* -* ................ ENTRY (ISAVE( 1 ) = 3) -* X HAS BEEN OVERWRITTEN BY A*X. -* - 70 CONTINUE - CALL DCOPY( N, X, 1, V, 1 ) - ESTOLD = EST - EST = DASUM( N, V, 1 ) - DO 80 I = 1, N - IF( NINT( SIGN( ONE, X( I ) ) ).NE.ISGN( I ) ) - $ GO TO 90 - 80 CONTINUE -* REPEATED SIGN VECTOR DETECTED, HENCE ALGORITHM HAS CONVERGED. - GO TO 120 -* - 90 CONTINUE -* TEST FOR CYCLING. - IF( EST.LE.ESTOLD ) - $ GO TO 120 -* - DO 100 I = 1, N - X( I ) = SIGN( ONE, X( I ) ) - ISGN( I ) = NINT( X( I ) ) - 100 CONTINUE - KASE = 2 - ISAVE( 1 ) = 4 - RETURN -* -* ................ ENTRY (ISAVE( 1 ) = 4) -* X HAS BEEN OVERWRITTEN BY TRANSPOSE(A)*X. -* - 110 CONTINUE - JLAST = ISAVE( 2 ) - ISAVE( 2 ) = IDAMAX( N, X, 1 ) - IF( ( X( JLAST ).NE.ABS( X( ISAVE( 2 ) ) ) ) .AND. - $ ( ISAVE( 3 ).LT.ITMAX ) ) THEN - ISAVE( 3 ) = ISAVE( 3 ) + 1 - GO TO 50 - END IF -* -* ITERATION COMPLETE. FINAL STAGE. -* - 120 CONTINUE - ALTSGN = ONE - DO 130 I = 1, N - X( I ) = ALTSGN*( ONE+DBLE( I-1 ) / DBLE( N-1 ) ) - ALTSGN = -ALTSGN - 130 CONTINUE - KASE = 1 - ISAVE( 1 ) = 5 - RETURN -* -* ................ ENTRY (ISAVE( 1 ) = 5) -* X HAS BEEN OVERWRITTEN BY A*X. -* - 140 CONTINUE - TEMP = TWO*( DASUM( N, X, 1 ) / DBLE( 3*N ) ) - IF( TEMP.GT.EST ) THEN - CALL DCOPY( N, X, 1, V, 1 ) - EST = TEMP - END IF -* - 150 CONTINUE - KASE = 0 - RETURN -* -* End of DLACN2 -* - END |