Squashed 'third_party/eigen/' content from commit 61d72f6
Change-Id: Iccc90fa0b55ab44037f018046d2fcffd90d9d025
git-subtree-dir: third_party/eigen
git-subtree-split: 61d72f6383cfa842868c53e30e087b0258177257
diff --git a/blas/drotmg.f b/blas/drotmg.f
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+++ b/blas/drotmg.f
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+ SUBROUTINE DROTMG(DD1,DD2,DX1,DY1,DPARAM)
+* .. Scalar Arguments ..
+ DOUBLE PRECISION DD1,DD2,DX1,DY1
+* ..
+* .. Array Arguments ..
+ DOUBLE PRECISION DPARAM(5)
+* ..
+*
+* Purpose
+* =======
+*
+* CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS
+* THE SECOND COMPONENT OF THE 2-VECTOR (DSQRT(DD1)*DX1,DSQRT(DD2)*
+* DY2)**T.
+* WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS..
+*
+* DFLAG=-1.D0 DFLAG=0.D0 DFLAG=1.D0 DFLAG=-2.D0
+*
+* (DH11 DH12) (1.D0 DH12) (DH11 1.D0) (1.D0 0.D0)
+* H=( ) ( ) ( ) ( )
+* (DH21 DH22), (DH21 1.D0), (-1.D0 DH22), (0.D0 1.D0).
+* LOCATIONS 2-4 OF DPARAM CONTAIN DH11, DH21, DH12, AND DH22
+* RESPECTIVELY. (VALUES OF 1.D0, -1.D0, OR 0.D0 IMPLIED BY THE
+* VALUE OF DPARAM(1) ARE NOT STORED IN DPARAM.)
+*
+* THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE
+* INEXACT. THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE
+* OF DD1 AND DD2. ALL ACTUAL SCALING OF DATA IS DONE USING GAM.
+*
+*
+* Arguments
+* =========
+*
+* DD1 (input/output) DOUBLE PRECISION
+*
+* DD2 (input/output) DOUBLE PRECISION
+*
+* DX1 (input/output) DOUBLE PRECISION
+*
+* DY1 (input) DOUBLE PRECISION
+*
+* DPARAM (input/output) DOUBLE PRECISION array, dimension 5
+* DPARAM(1)=DFLAG
+* DPARAM(2)=DH11
+* DPARAM(3)=DH21
+* DPARAM(4)=DH12
+* DPARAM(5)=DH22
+*
+* =====================================================================
+*
+* .. Local Scalars ..
+ DOUBLE PRECISION DFLAG,DH11,DH12,DH21,DH22,DP1,DP2,DQ1,DQ2,DTEMP,
+ + DU,GAM,GAMSQ,ONE,RGAMSQ,TWO,ZERO
+ INTEGER IGO
+* ..
+* .. Intrinsic Functions ..
+ INTRINSIC DABS
+* ..
+* .. Data statements ..
+*
+ DATA ZERO,ONE,TWO/0.D0,1.D0,2.D0/
+ DATA GAM,GAMSQ,RGAMSQ/4096.D0,16777216.D0,5.9604645D-8/
+* ..
+
+ IF (.NOT.DD1.LT.ZERO) GO TO 10
+* GO ZERO-H-D-AND-DX1..
+ GO TO 60
+ 10 CONTINUE
+* CASE-DD1-NONNEGATIVE
+ DP2 = DD2*DY1
+ IF (.NOT.DP2.EQ.ZERO) GO TO 20
+ DFLAG = -TWO
+ GO TO 260
+* REGULAR-CASE..
+ 20 CONTINUE
+ DP1 = DD1*DX1
+ DQ2 = DP2*DY1
+ DQ1 = DP1*DX1
+*
+ IF (.NOT.DABS(DQ1).GT.DABS(DQ2)) GO TO 40
+ DH21 = -DY1/DX1
+ DH12 = DP2/DP1
+*
+ DU = ONE - DH12*DH21
+*
+ IF (.NOT.DU.LE.ZERO) GO TO 30
+* GO ZERO-H-D-AND-DX1..
+ GO TO 60
+ 30 CONTINUE
+ DFLAG = ZERO
+ DD1 = DD1/DU
+ DD2 = DD2/DU
+ DX1 = DX1*DU
+* GO SCALE-CHECK..
+ GO TO 100
+ 40 CONTINUE
+ IF (.NOT.DQ2.LT.ZERO) GO TO 50
+* GO ZERO-H-D-AND-DX1..
+ GO TO 60
+ 50 CONTINUE
+ DFLAG = ONE
+ DH11 = DP1/DP2
+ DH22 = DX1/DY1
+ DU = ONE + DH11*DH22
+ DTEMP = DD2/DU
+ DD2 = DD1/DU
+ DD1 = DTEMP
+ DX1 = DY1*DU
+* GO SCALE-CHECK
+ GO TO 100
+* PROCEDURE..ZERO-H-D-AND-DX1..
+ 60 CONTINUE
+ DFLAG = -ONE
+ DH11 = ZERO
+ DH12 = ZERO
+ DH21 = ZERO
+ DH22 = ZERO
+*
+ DD1 = ZERO
+ DD2 = ZERO
+ DX1 = ZERO
+* RETURN..
+ GO TO 220
+* PROCEDURE..FIX-H..
+ 70 CONTINUE
+ IF (.NOT.DFLAG.GE.ZERO) GO TO 90
+*
+ IF (.NOT.DFLAG.EQ.ZERO) GO TO 80
+ DH11 = ONE
+ DH22 = ONE
+ DFLAG = -ONE
+ GO TO 90
+ 80 CONTINUE
+ DH21 = -ONE
+ DH12 = ONE
+ DFLAG = -ONE
+ 90 CONTINUE
+ GO TO IGO(120,150,180,210)
+* PROCEDURE..SCALE-CHECK
+ 100 CONTINUE
+ 110 CONTINUE
+ IF (.NOT.DD1.LE.RGAMSQ) GO TO 130
+ IF (DD1.EQ.ZERO) GO TO 160
+ ASSIGN 120 TO IGO
+* FIX-H..
+ GO TO 70
+ 120 CONTINUE
+ DD1 = DD1*GAM**2
+ DX1 = DX1/GAM
+ DH11 = DH11/GAM
+ DH12 = DH12/GAM
+ GO TO 110
+ 130 CONTINUE
+ 140 CONTINUE
+ IF (.NOT.DD1.GE.GAMSQ) GO TO 160
+ ASSIGN 150 TO IGO
+* FIX-H..
+ GO TO 70
+ 150 CONTINUE
+ DD1 = DD1/GAM**2
+ DX1 = DX1*GAM
+ DH11 = DH11*GAM
+ DH12 = DH12*GAM
+ GO TO 140
+ 160 CONTINUE
+ 170 CONTINUE
+ IF (.NOT.DABS(DD2).LE.RGAMSQ) GO TO 190
+ IF (DD2.EQ.ZERO) GO TO 220
+ ASSIGN 180 TO IGO
+* FIX-H..
+ GO TO 70
+ 180 CONTINUE
+ DD2 = DD2*GAM**2
+ DH21 = DH21/GAM
+ DH22 = DH22/GAM
+ GO TO 170
+ 190 CONTINUE
+ 200 CONTINUE
+ IF (.NOT.DABS(DD2).GE.GAMSQ) GO TO 220
+ ASSIGN 210 TO IGO
+* FIX-H..
+ GO TO 70
+ 210 CONTINUE
+ DD2 = DD2/GAM**2
+ DH21 = DH21*GAM
+ DH22 = DH22*GAM
+ GO TO 200
+ 220 CONTINUE
+ IF (DFLAG) 250,230,240
+ 230 CONTINUE
+ DPARAM(3) = DH21
+ DPARAM(4) = DH12
+ GO TO 260
+ 240 CONTINUE
+ DPARAM(2) = DH11
+ DPARAM(5) = DH22
+ GO TO 260
+ 250 CONTINUE
+ DPARAM(2) = DH11
+ DPARAM(3) = DH21
+ DPARAM(4) = DH12
+ DPARAM(5) = DH22
+ 260 CONTINUE
+ DPARAM(1) = DFLAG
+ RETURN
+ END