Fix using Safe Minimum

Author: weslleyspereira

SRC/ctgsja.f

@@ -409,12 +409,13 @@ SUBROUTINE CTGSJA( JOBU, JOBV, JOBQ, M, P, N, K, L, A, LDA, B,
       LOGICAL            INITQ, INITU, INITV, UPPER, WANTQ, WANTU, WANTV
       INTEGER            I, J, KCYCLE
       REAL               A1, A3, B1, B3, CSQ, CSU, CSV, ERROR, GAMMA,
-     $                   RWK, SSMIN
+     $                   RWK, SSMIN, SFMIN
       COMPLEX            A2, B2, SNQ, SNU, SNV
 *     ..
 *     .. External Functions ..
       LOGICAL            LSAME
-      EXTERNAL           LSAME
+      REAL               SLAMCH
+      EXTERNAL           LSAME, SLAMCH
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           CCOPY, CLAGS2, CLAPLL, CLASET, CROT, CSSCAL,
@@ -465,6 +466,10 @@ SUBROUTINE CTGSJA( JOBU, JOBV, JOBQ, M, P, N, K, L, A, LDA, B,
          RETURN
       END IF
 *
+*     Safe minimum
+*
+      SFMIN = SLAMCH( 'Safe minimum' )
+*
 *     Initialize U, V and Q, if necessary
 *
       IF( INITU )
@@ -608,7 +613,7 @@ SUBROUTINE CTGSJA( JOBU, JOBV, JOBQ, M, P, N, K, L, A, LDA, B,
          A1 = REAL( A( K+I, N-L+I ) )
          B1 = REAL( B( I, N-L+I ) )
 *
-         IF( A1.NE.ZERO ) THEN
+         IF( ABS(A1).GE.SFMIN ) THEN
             GAMMA = B1 / A1
 *
             IF( GAMMA.LT.ZERO ) THEN