Break out of potentially infinite rescaling loop after 1000 iterations

Inf values in the input vector will survive rescaling, causing an infinite loop. The value of 1000 is arbitrarily chosen as a large but finite value with the intention to never interfere with regular calculations.

Author: martin-frbg

lapack-netlib/SRC/clarfg.f

@@ -175,7 +175,7 @@ SUBROUTINE CLARFG( N, ALPHA, X, INCX, TAU )
             BETA = BETA*RSAFMN
             ALPHI = ALPHI*RSAFMN
             ALPHR = ALPHR*RSAFMN
-            IF( ABS( BETA ).LT.SAFMIN )
+            IF( ABS( BETA ).LT.SAFMIN .AND. KNT .LT. 1000)
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SAFMIN

lapack-netlib/SRC/clarfgp.f

@@ -197,7 +197,7 @@ SUBROUTINE CLARFGP( N, ALPHA, X, INCX, TAU )
             BETA = BETA*BIGNUM
             ALPHI = ALPHI*BIGNUM
             ALPHR = ALPHR*BIGNUM
-            IF( ABS( BETA ).LT.SMLNUM )
+            IF( ABS( BETA ).LT.SMLNUM .AND. KNT .LT. 1000 )
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SMLNUM

lapack-netlib/SRC/dlarfg.f

@@ -170,7 +170,7 @@ SUBROUTINE DLARFG( N, ALPHA, X, INCX, TAU )
             CALL DSCAL( N-1, RSAFMN, X, INCX )
             BETA = BETA*RSAFMN
             ALPHA = ALPHA*RSAFMN
-            IF( ABS( BETA ).LT.SAFMIN )
+            IF( ABS( BETA ).LT.SAFMIN .AND. KNT .LT. 1000 )
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SAFMIN

lapack-netlib/SRC/dlarfgp.f

@@ -181,7 +181,7 @@ SUBROUTINE DLARFGP( N, ALPHA, X, INCX, TAU )
             CALL DSCAL( N-1, BIGNUM, X, INCX )
             BETA = BETA*BIGNUM
             ALPHA = ALPHA*BIGNUM
-            IF( ABS( BETA ).LT.SMLNUM )
+            IF( ABS( BETA ).LT.SMLNUM .AND. KNT .LT. 1000)
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SMLNUM

lapack-netlib/SRC/slarfg.f

@@ -170,7 +170,7 @@ SUBROUTINE SLARFG( N, ALPHA, X, INCX, TAU )
             CALL SSCAL( N-1, RSAFMN, X, INCX )
             BETA = BETA*RSAFMN
             ALPHA = ALPHA*RSAFMN
-            IF( ABS( BETA ).LT.SAFMIN )
+            IF( ABS( BETA ).LT.SAFMIN .AND. KNT .LT. 1000)
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SAFMIN

lapack-netlib/SRC/slarfgp.f

@@ -181,7 +181,7 @@ SUBROUTINE SLARFGP( N, ALPHA, X, INCX, TAU )
             CALL SSCAL( N-1, BIGNUM, X, INCX )
             BETA = BETA*BIGNUM
             ALPHA = ALPHA*BIGNUM
-            IF( ABS( BETA ).LT.SMLNUM )
+            IF( ABS( BETA ).LT.SMLNUM .AND. KNT .LT. 1000 )
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SMLNUM

lapack-netlib/SRC/zlarfg.f

@@ -175,7 +175,7 @@ SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU )
             BETA = BETA*RSAFMN
             ALPHI = ALPHI*RSAFMN
             ALPHR = ALPHR*RSAFMN
-            IF( ABS( BETA ).LT.SAFMIN )
+            IF( ABS( BETA ).LT.SAFMIN .AND. KNT .LT. 1000)
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SAFMIN

lapack-netlib/SRC/zlarfgp.f

@@ -197,7 +197,7 @@ SUBROUTINE ZLARFGP( N, ALPHA, X, INCX, TAU )
             BETA = BETA*BIGNUM
             ALPHI = ALPHI*BIGNUM
             ALPHR = ALPHR*BIGNUM
-            IF( ABS( BETA ).LT.SMLNUM )
+            IF( ABS( BETA ).LT.SMLNUM .AND. KNT .LT. 1000)
      $         GO TO 10
 *
 *           New BETA is at most 1, at least SMLNUM