Fix [CDSZ]QRT17.

This is a routine to test DGELS which solves solves full rank overdetermined ( linear least squares ) or underdetermined (minimum norm) linear systems.

The check is, as follows,

(1) If the system is consistent, (smallresidual,) we check that
|| A^T ( b – A * x ) || / (||A||*||b||*max(M,N,NRHS)*eps)
is small (say less than 30).

(2) If the system is not consistent, (large residual,) we check that
|| A^T ( b – A * x ) || / (||A||*|| b - A*x ||*max(M,N,NRHS)*eps)
is small (say less than 30).

DQRT17 was checking in the not consistent case (large residual) that
|| A^T ( b – A * x ) || / (||A||*||x||*max(M,N,NRHS)*eps)
is small. It is a mistake and we need to change the ||x|| by a ||r||.

This fix is consistent with what the documentation says and makes more sense.

diff --git a/TESTING/LIN/cqrt17.f b/TESTING/LIN/cqrt17.f
index 623d7f06b4e7ffb588180f2e5eb9c422f8023f64..a4109aabd4c4e8d0c93e2b0fd38aa60fdcfd6538 100644 (file)
--- a/TESTING/LIN/cqrt17.f
+++ b/TESTING/LIN/cqrt17.f
@@ -249,9 +249,8 @@
          IF( NORMB.NE.ZERO )
      $      ERR = ERR / NORMB
       ELSE
-         NORMX = CLANGE( 'One-norm', NCOLS, NRHS, X, LDX, RWORK )
-         IF( NORMX.NE.ZERO )
-     $      ERR = ERR / NORMX
+         IF( NORMRS.NE.ZERO )
+     $      ERR = ERR / NORMRS
       END IF
 *
       CQRT17 = ERR / ( SLAMCH( 'Epsilon' )*REAL( MAX( M, N, NRHS ) ) )

diff --git a/TESTING/LIN/dqrt17.f b/TESTING/LIN/dqrt17.f
index 625aba46b678f83dae427062d0af3def55d8429a..8637d82cb76b455b3844db5e3a465ebc777f9512 100644 (file)
--- a/TESTING/LIN/dqrt17.f
+++ b/TESTING/LIN/dqrt17.f
@@ -249,9 +249,8 @@
          IF( NORMB.NE.ZERO )
      $      ERR = ERR / NORMB
       ELSE
-         NORMX = DLANGE( 'One-norm', NCOLS, NRHS, X, LDX, RWORK )
-         IF( NORMX.NE.ZERO )
-     $      ERR = ERR / NORMX
+         IF( NORMRS.NE.ZERO )
+     $      ERR = ERR / NORMRS
       END IF
 *
       DQRT17 = ERR / ( DLAMCH( 'Epsilon' )*DBLE( MAX( M, N, NRHS ) ) )

diff --git a/TESTING/LIN/sqrt17.f b/TESTING/LIN/sqrt17.f
index 720eb14d81c0f81ea93f22830b611f4b2ff1b8b9..d87bf16a9a68c555bec846a53c0d72ceb50ae53f 100644 (file)
--- a/TESTING/LIN/sqrt17.f
+++ b/TESTING/LIN/sqrt17.f
@@ -249,9 +249,8 @@
          IF( NORMB.NE.ZERO )
      $      ERR = ERR / NORMB
       ELSE
-         NORMX = SLANGE( 'One-norm', NCOLS, NRHS, X, LDX, RWORK )
-         IF( NORMX.NE.ZERO )
-     $      ERR = ERR / NORMX
+         IF( NORMRS.NE.ZERO )
+     $      ERR = ERR / NORMRS
       END IF
 *
       SQRT17 = ERR / ( SLAMCH( 'Epsilon' )*REAL( MAX( M, N, NRHS ) ) )

diff --git a/TESTING/LIN/zqrt17.f b/TESTING/LIN/zqrt17.f
index 5e69ddd4feec2e72c193b5b5980377b3ec4acbe6..a1663cb86cb83c6c17805b3b137545c1b8de68a6 100644 (file)
--- a/TESTING/LIN/zqrt17.f
+++ b/TESTING/LIN/zqrt17.f
@@ -250,9 +250,8 @@
          IF( NORMB.NE.ZERO )
      $      ERR = ERR / NORMB
       ELSE
-         NORMX = ZLANGE( 'One-norm', NCOLS, NRHS, X, LDX, RWORK )
-         IF( NORMX.NE.ZERO )
-     $      ERR = ERR / NORMX
+         IF( NORMRS.NE.ZERO )
+     $      ERR = ERR / NORMRS
       END IF
 *
       ZQRT17 = ERR / ( DLAMCH( 'Epsilon' )*DBLE( MAX( M, N, NRHS ) ) )