fix lastv possible range in clarf1f, Reference-LAPACK#1011

EduardFedorenkov · Jun 6, 2024 · ea943fc · ea943fc
1 parent 1d4010e
commit ea943fc
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/SRC/clarf1f.f b/SRC/clarf1f.f
@@ -164,11 +164,11 @@ SUBROUTINE CLARF1F( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
 *     .. Executable Statements ..
 *
       APPLYLEFT = LSAME( SIDE, 'L' )
-      LASTV = 0
+      LASTV = 1
       LASTC = 0
       IF( TAU.NE.ZERO ) THEN
 !     Set up variables for scanning V.  LASTV begins pointing to the end
-!     of V.
+!     of V up to V(1).
          IF( APPLYLEFT ) THEN
             LASTV = M
          ELSE
@@ -180,7 +180,7 @@ SUBROUTINE CLARF1F( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
             I = 1
          END IF
 !     Look for the last non-zero row in V.
-         DO WHILE( LASTV.GT.0 .AND. V( I ).EQ.ZERO )
+         DO WHILE( LASTV.GT.1 .AND. V( I ).EQ.ZERO )
             LASTV = LASTV - 1
             I = I - INCV
          END DO
@@ -192,7 +192,7 @@ SUBROUTINE CLARF1F( SIDE, M, N, V, INCV, TAU, C, LDC, WORK )
             LASTC = ILACLR(M, LASTV, C, LDC)
          END IF
       END IF
-      IF( LASTC.EQ.0 .OR. LASTV.EQ.0 ) THEN
+      IF( LASTC.EQ.0 ) THEN
          RETURN
       END IF
       IF( APPLYLEFT ) THEN