Harmonize [SD]TREVC[3] with its complex counterpart

Compute majorant through a call to the BLAS as done in [CZ]TREVC[3]
Reference-LAPACK · Jun 19, 2022 · b3caae4 · b3caae4
1 parent fc19446
commit b3caae4
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Showing 4 changed files with 12 additions and 24 deletions.
diff --git a/SRC/dtrevc.f b/SRC/dtrevc.f
@@ -250,8 +250,8 @@ SUBROUTINE DTREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *     .. External Functions ..
       LOGICAL            LSAME
       INTEGER            IDAMAX
-      DOUBLE PRECISION   DDOT, DLAMCH
-      EXTERNAL           LSAME, IDAMAX, DDOT, DLAMCH
+      DOUBLE PRECISION   DASUM, DDOT, DLAMCH
+      EXTERNAL           DASUM, LSAME, IDAMAX, DDOT, DLAMCH
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           DLABAD, DAXPY, DCOPY, DGEMV, DLALN2, DSCAL,
@@ -351,10 +351,7 @@ SUBROUTINE DTREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *
       WORK( 1 ) = ZERO
       DO 30 J = 2, N
-         WORK( J ) = ZERO
-         DO 20 I = 1, J - 1
-            WORK( J ) = WORK( J ) + ABS( T( I, J ) )
-   20    CONTINUE
+         WORK( J ) = DASUM( J-1, T( I, J ), 1 )
    30 CONTINUE
 *
 *     Index IP is used to specify the real or complex eigenvalue:

diff --git a/SRC/dtrevc3.f b/SRC/dtrevc3.f
@@ -270,8 +270,8 @@ SUBROUTINE DTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *     .. External Functions ..
       LOGICAL            LSAME
       INTEGER            IDAMAX, ILAENV
-      DOUBLE PRECISION   DDOT, DLAMCH
-      EXTERNAL           LSAME, IDAMAX, ILAENV, DDOT, DLAMCH
+      DOUBLE PRECISION   DASUM, DDOT, DLAMCH
+      EXTERNAL           DASUM, LSAME, IDAMAX, ILAENV, DDOT, DLAMCH
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           DAXPY, DCOPY, DGEMV, DLALN2, DSCAL, XERBLA,
@@ -391,10 +391,7 @@ SUBROUTINE DTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *
       WORK( 1 ) = ZERO
       DO 30 J = 2, N
-         WORK( J ) = ZERO
-         DO 20 I = 1, J - 1
-            WORK( J ) = WORK( J ) + ABS( T( I, J ) )
-   20    CONTINUE
+         WORK( J ) = DASUM( J-1, T( I, J ), 1 )
    30 CONTINUE
 *
 *     Index IP is used to specify the real or complex eigenvalue:

diff --git a/SRC/strevc.f b/SRC/strevc.f
@@ -250,8 +250,8 @@ SUBROUTINE STREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *     .. External Functions ..
       LOGICAL            LSAME
       INTEGER            ISAMAX
-      REAL               SDOT, SLAMCH
-      EXTERNAL           LSAME, ISAMAX, SDOT, SLAMCH
+      REAL               SASUM, SDOT, SLAMCH
+      EXTERNAL           SASUM, LSAME, ISAMAX, SDOT, SLAMCH
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           SAXPY, SCOPY, SGEMV, SLABAD, SLALN2, SSCAL,
@@ -351,10 +351,7 @@ SUBROUTINE STREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *
       WORK( 1 ) = ZERO
       DO 30 J = 2, N
-         WORK( J ) = ZERO
-         DO 20 I = 1, J - 1
-            WORK( J ) = WORK( J ) + ABS( T( I, J ) )
-   20    CONTINUE
+         WORK( J ) = SASUM( J-1, T( I, J ), 1 )
    30 CONTINUE
 *
 *     Index IP is used to specify the real or complex eigenvalue:

diff --git a/SRC/strevc3.f b/SRC/strevc3.f
@@ -270,8 +270,8 @@ SUBROUTINE STREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *     .. External Functions ..
       LOGICAL            LSAME
       INTEGER            ISAMAX, ILAENV
-      REAL   SDOT, SLAMCH
-      EXTERNAL           LSAME, ISAMAX, ILAENV, SDOT, SLAMCH
+      REAL               SASUM, SDOT, SLAMCH
+      EXTERNAL           SASUM, LSAME, ISAMAX, ILAENV, SDOT, SLAMCH
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           SAXPY, SCOPY, SGEMV, SLALN2, SSCAL, XERBLA,
@@ -391,10 +391,7 @@ SUBROUTINE STREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *
       WORK( 1 ) = ZERO
       DO 30 J = 2, N
-         WORK( J ) = ZERO
-         DO 20 I = 1, J - 1
-            WORK( J ) = WORK( J ) + ABS( T( I, J ) )
-   20    CONTINUE
+         WORK( J ) = SASUM( J-1, T( I, J ), 1 )
    30 CONTINUE
 *
 *     Index IP is used to specify the real or complex eigenvalue: