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Diffstat (limited to 'src/lib/lapack/dlartg.f')
| -rw-r--r-- | src/lib/lapack/dlartg.f | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/src/lib/lapack/dlartg.f b/src/lib/lapack/dlartg.f deleted file mode 100644 index eb807c1d..00000000 --- a/src/lib/lapack/dlartg.f +++ /dev/null @@ -1,145 +0,0 @@ - SUBROUTINE DLARTG( F, G, CS, SN, R ) -* -* -- LAPACK auxiliary routine (version 3.1) -- -* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. -* November 2006 -* -* .. Scalar Arguments .. - DOUBLE PRECISION CS, F, G, R, SN -* .. -* -* Purpose -* ======= -* -* DLARTG generate a plane rotation so that -* -* [ CS SN ] . [ F ] = [ R ] where CS**2 + SN**2 = 1. -* [ -SN CS ] [ G ] [ 0 ] -* -* This is a slower, more accurate version of the BLAS1 routine DROTG, -* with the following other differences: -* F and G are unchanged on return. -* If G=0, then CS=1 and SN=0. -* If F=0 and (G .ne. 0), then CS=0 and SN=1 without doing any -* floating point operations (saves work in DBDSQR when -* there are zeros on the diagonal). -* -* If F exceeds G in magnitude, CS will be positive. -* -* Arguments -* ========= -* -* F (input) DOUBLE PRECISION -* The first component of vector to be rotated. -* -* G (input) DOUBLE PRECISION -* The second component of vector to be rotated. -* -* CS (output) DOUBLE PRECISION -* The cosine of the rotation. -* -* SN (output) DOUBLE PRECISION -* The sine of the rotation. -* -* R (output) DOUBLE PRECISION -* The nonzero component of the rotated vector. -* -* This version has a few statements commented out for thread safety -* (machine parameters are computed on each entry). 10 feb 03, SJH. -* -* ===================================================================== -* -* .. Parameters .. - DOUBLE PRECISION ZERO - PARAMETER ( ZERO = 0.0D0 ) - DOUBLE PRECISION ONE - PARAMETER ( ONE = 1.0D0 ) - DOUBLE PRECISION TWO - PARAMETER ( TWO = 2.0D0 ) -* .. -* .. Local Scalars .. -* LOGICAL FIRST - INTEGER COUNT, I - DOUBLE PRECISION EPS, F1, G1, SAFMIN, SAFMN2, SAFMX2, SCALE -* .. -* .. External Functions .. - DOUBLE PRECISION DLAMCH - EXTERNAL DLAMCH -* .. -* .. Intrinsic Functions .. - INTRINSIC ABS, INT, LOG, MAX, SQRT -* .. -* .. Save statement .. -* SAVE FIRST, SAFMX2, SAFMIN, SAFMN2 -* .. -* .. Data statements .. -* DATA FIRST / .TRUE. / -* .. -* .. Executable Statements .. -* -* IF( FIRST ) THEN - SAFMIN = DLAMCH( 'S' ) - EPS = DLAMCH( 'E' ) - SAFMN2 = DLAMCH( 'B' )**INT( LOG( SAFMIN / EPS ) / - $ LOG( DLAMCH( 'B' ) ) / TWO ) - SAFMX2 = ONE / SAFMN2 -* FIRST = .FALSE. -* END IF - IF( G.EQ.ZERO ) THEN - CS = ONE - SN = ZERO - R = F - ELSE IF( F.EQ.ZERO ) THEN - CS = ZERO - SN = ONE - R = G - ELSE - F1 = F - G1 = G - SCALE = MAX( ABS( F1 ), ABS( G1 ) ) - IF( SCALE.GE.SAFMX2 ) THEN - COUNT = 0 - 10 CONTINUE - COUNT = COUNT + 1 - F1 = F1*SAFMN2 - G1 = G1*SAFMN2 - SCALE = MAX( ABS( F1 ), ABS( G1 ) ) - IF( SCALE.GE.SAFMX2 ) - $ GO TO 10 - R = SQRT( F1**2+G1**2 ) - CS = F1 / R - SN = G1 / R - DO 20 I = 1, COUNT - R = R*SAFMX2 - 20 CONTINUE - ELSE IF( SCALE.LE.SAFMN2 ) THEN - COUNT = 0 - 30 CONTINUE - COUNT = COUNT + 1 - F1 = F1*SAFMX2 - G1 = G1*SAFMX2 - SCALE = MAX( ABS( F1 ), ABS( G1 ) ) - IF( SCALE.LE.SAFMN2 ) - $ GO TO 30 - R = SQRT( F1**2+G1**2 ) - CS = F1 / R - SN = G1 / R - DO 40 I = 1, COUNT - R = R*SAFMN2 - 40 CONTINUE - ELSE - R = SQRT( F1**2+G1**2 ) - CS = F1 / R - SN = G1 / R - END IF - IF( ABS( F ).GT.ABS( G ) .AND. CS.LT.ZERO ) THEN - CS = -CS - SN = -SN - R = -R - END IF - END IF - RETURN -* -* End of DLARTG -* - END |