Added check for NaN in input parameter G to avoid infinite loop -- fixes bug110.

diff --git a/SRC/clartg.f b/SRC/clartg.f
index a720f1d0b91f1d645af19a45b70df980ce709023..327fdb098e2cdfa0eaac5b49e21faac6d1621e52 100644 (file)
--- a/SRC/clartg.f
+++ b/SRC/clartg.f
@@ -130,7 +130,8 @@
 *     ..
 *     .. External Functions ..
       REAL               SLAMCH, SLAPY2
-      EXTERNAL           SLAMCH, SLAPY2
+      LOGICAL            SISNAN
+      EXTERNAL           SLAMCH, SLAPY2, SISNAN
 *     ..
 *     .. Intrinsic Functions ..
       INTRINSIC          ABS, AIMAG, CMPLX, CONJG, INT, LOG, MAX, REAL,
@@ -139,26 +140,17 @@
 *     .. Statement Functions ..
       REAL               ABS1, ABSSQ
 *     ..
-*     .. Save statement ..
-*     SAVE               FIRST, SAFMX2, SAFMIN, SAFMN2
-*     ..
-*     .. Data statements ..
-*     DATA               FIRST / .TRUE. /
-*     ..
 *     .. Statement Function definitions ..
       ABS1( FF ) = MAX( ABS( REAL( FF ) ), ABS( AIMAG( FF ) ) )
       ABSSQ( FF ) = REAL( FF )**2 + AIMAG( FF )**2
 *     ..
 *     .. Executable Statements ..
 *
-*     IF( FIRST ) THEN
-         SAFMIN = SLAMCH( 'S' )
-         EPS = SLAMCH( 'E' )
-         SAFMN2 = SLAMCH( 'B' )**INT( LOG( SAFMIN / EPS ) /
-     $            LOG( SLAMCH( 'B' ) ) / TWO )
-         SAFMX2 = ONE / SAFMN2
-*        FIRST = .FALSE.
-*     END IF
+      SAFMIN = SLAMCH( 'S' )
+      EPS = SLAMCH( 'E' )
+      SAFMN2 = SLAMCH( 'B' )**INT( LOG( SAFMIN / EPS ) /
+     $         LOG( SLAMCH( 'B' ) ) / TWO )
+      SAFMX2 = ONE / SAFMN2
       SCALE = MAX( ABS1( F ), ABS1( G ) )
       FS = F
       GS = G
@@ -172,7 +164,7 @@
          IF( SCALE.GE.SAFMX2 )
      $      GO TO 10
       ELSE IF( SCALE.LE.SAFMN2 ) THEN
-         IF( G.EQ.CZERO ) THEN
+         IF( G.EQ.CZERO.OR.SISNAN( ABS( G ) ) ) THEN
             CS = ONE
             SN = CZERO
             R = F

diff --git a/SRC/zlartg.f b/SRC/zlartg.f
index e790021c6c5f8d629b059c69923fc3d7ba8e5d13..0af91dc4a024c1dc3883d202ca2a1fc929fa5591 100644 (file)
--- a/SRC/zlartg.f
+++ b/SRC/zlartg.f
@@ -130,7 +130,8 @@
 *     ..
 *     .. External Functions ..
       DOUBLE PRECISION   DLAMCH, DLAPY2
-      EXTERNAL           DLAMCH, DLAPY2
+      LOGICAL            DISNAN
+      EXTERNAL           DLAMCH, DLAPY2, DISNAN
 *     ..
 *     .. Intrinsic Functions ..
       INTRINSIC          ABS, DBLE, DCMPLX, DCONJG, DIMAG, INT, LOG,
@@ -139,26 +140,17 @@
 *     .. Statement Functions ..
       DOUBLE PRECISION   ABS1, ABSSQ
 *     ..
-*     .. Save statement ..
-*     SAVE               FIRST, SAFMX2, SAFMIN, SAFMN2
-*     ..
-*     .. Data statements ..
-*     DATA               FIRST / .TRUE. /
-*     ..
 *     .. Statement Function definitions ..
       ABS1( FF ) = MAX( ABS( DBLE( FF ) ), ABS( DIMAG( FF ) ) )
       ABSSQ( FF ) = DBLE( FF )**2 + DIMAG( FF )**2
 *     ..
 *     .. Executable Statements ..
 *
-*     IF( FIRST ) THEN
-         SAFMIN = DLAMCH( 'S' )
-         EPS = DLAMCH( 'E' )
-         SAFMN2 = DLAMCH( 'B' )**INT( LOG( SAFMIN / EPS ) /
-     $            LOG( DLAMCH( 'B' ) ) / TWO )
-         SAFMX2 = ONE / SAFMN2
-*        FIRST = .FALSE.
-*     END IF
+      SAFMIN = DLAMCH( 'S' )
+      EPS = DLAMCH( 'E' )
+      SAFMN2 = DLAMCH( 'B' )**INT( LOG( SAFMIN / EPS ) /
+     $         LOG( DLAMCH( 'B' ) ) / TWO )
+      SAFMX2 = ONE / SAFMN2
       SCALE = MAX( ABS1( F ), ABS1( G ) )
       FS = F
       GS = G
@@ -172,7 +164,7 @@
          IF( SCALE.GE.SAFMX2 )
      $      GO TO 10
       ELSE IF( SCALE.LE.SAFMN2 ) THEN
-         IF( G.EQ.CZERO ) THEN
+         IF( G.EQ.CZERO.OR.DISNAN( ABS( G ) ) ) THEN
             CS = ONE
             SN = CZERO
             R = F