added a few comments to the code in files for linear equations testing routines: schksy.f dchksy.f cchksy.f zchksy.f

1 files changed, 29 insertions, 8 deletions

diff --git a/TESTING/LIN/schksy.f b/TESTING/LIN/schksy.f
index f8965a59..c3b2e031 100644
--- a/TESTING/LIN/schksy.f
+++ b/TESTING/LIN/schksy.f
@@ -295,18 +295,22 @@
             DO 160 IUPLO = 1, 2
                UPLO = UPLOS( IUPLO )
 *
-*              Set up parameters with SLATB4 and generate a test matrix
-*              with SLATMS.
+*              Begin generate the test matrix A.
+*
+*              Set up parameters with SLATB4 for the matrix generator
+*              based on the type of matrix to be generated.
 *
                CALL SLATB4( PATH, IMAT, N, N, TYPE, KL, KU, ANORM, MODE,
      $                      CNDNUM, DIST )
 *
+*              Generate a matrix with SLATMS.
+*
                SRNAMT = 'SLATMS'
                CALL SLATMS( N, N, DIST, ISEED, TYPE, RWORK, MODE,
      $                      CNDNUM, ANORM, KL, KU, UPLO, A, LDA, WORK,
      $                      INFO )
 *
-*              Check error code from SLATMS.
+*              Check error code from SLATMS and handle error.
 *
                IF( INFO.NE.0 ) THEN
                   CALL ALAERH( PATH, 'SLATMS', INFO, 0, UPLO, N, N, -1,
@@ -314,8 +318,9 @@
                   GO TO 160
                END IF
 *
-*              For types 3-6, zero one or more rows and columns of
-*              the matrix to test that INFO is returned correctly.
+*              For matrix types 3-6, zero one or more rows and
+*              columns of the matrix to test that INFO is returned
+*              correctly.
 *
                IF( ZEROT ) THEN
                   IF( IMAT.EQ.3 ) THEN
@@ -381,16 +386,29 @@
                   IZERO = 0
                END IF
 *
+*              End generate the test matrix A.
+*
 *              Do for each value of NB in NBVAL
 *
                DO 150 INB = 1, NNB
+*
+*                 Set the optimal blocksize, which will be later
+*                 returned by ILAENV.
+*
                   NB = NBVAL( INB )
                   CALL XLAENV( 1, NB )
 *
-*                 Compute the L*D*L' or U*D*U' factorization of the
-*                 matrix.
+*                 Copy the test matrix A into matrix AFAC which
+*                 will be factorized in place. This is needed to
+*                 preserve the test matrix A for subsequent tests.
 *
                   CALL SLACPY( UPLO, N, N, A, LDA, AFAC, LDA )
+*
+*                 Compute the L*D*L**T or U*D*U**T factorization of the
+*                 matrix. IWORK stores details of the interchanges and
+*                 the block structure of D. AINV is a work array for
+*                 block factorization, LWORK is the length of AINV.
+*
                   LWORK = MAX( 2, NB )*LDA
                   SRNAMT = 'SSYTRF'
                   CALL SSYTRF( UPLO, N, AFAC, LDA, IWORK, AINV, LWORK,
@@ -413,11 +431,14 @@
                      END IF
                   END IF
 *
-*                 Check error code from SSYTRF.
+*                 Check error code from SSYTRF and handle error.
 *
                   IF( INFO.NE.K )
      $               CALL ALAERH( PATH, 'SSYTRF', INFO, K, UPLO, N, N,
      $                            -1, -1, NB, IMAT, NFAIL, NERRS, NOUT )
+*
+*                 Set the condition estimate flag if the INFO is not 0.
+*
                   IF( INFO.NE.0 ) THEN
                      TRFCON = .TRUE.
                   ELSE