changes to ILUCG subroutines

* change interface slightly
* revise convergence criteria


git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/AHFinderDirect/trunk@1093 f88db872-0e4f-0410-b76b-b9085cfa78c5

4 files changed, 47 insertions, 35 deletions

diff --git a/src/sparse-matrix/ilucg/dilucg.f77 b/src/sparse-matrix/ilucg/dilucg.f77
index 411240d..11d6c4b 100644
--- a/src/sparse-matrix/ilucg/dilucg.f77
+++ b/src/sparse-matrix/ilucg/dilucg.f77
@@ -1,8 +1,9 @@
-      SUBROUTINE DILUCG(N,IA,JA,A,
+      SUBROUTINE DILUCG(N,
+     $                  IA,JA,A,
      $                  B,X,
      $                  ITEMP,RTEMP,
-     $                  EPS,ITER,
-     $                  ISTATUS,IERROR)
+     $                  EPS,MAXITER,
+     $                  ISTATUS)
       IMPLICIT DOUBLE PRECISION (A-H,O-Z)
       DIMENSION IA(*),JA(*),A(*),B(*),X(*),ITEMP(*),RTEMP(*)
 C
@@ -32,21 +33,21 @@ C       INFINITY-NORM OF THE CURRENT SOLUTION.  HOWEVER, IF EPS
 C       .LT. 0.0D0, IT IS INTERNALLY SCALED BY THE MACHINE PRECISION,
 C       SO THAT, FOR EXAMPLE, EPS = -256.0D0 WILL ALLOW THE LAST 8 BITS
 C       OF THE SOLUTION TO BE IN ERROR.
-C     ITER GIVES THE REQUESTED NUMBER OF ITERATIONS, OR IS 0 FOR "NO LIMIT".
-C     ISTATUS IS AN INTEGER VARIABLE.  FOR NORMAL RETURN, IT GIVES
-C       THE NUMBER OF ITERATIONS DONE (NEGATIVE IS NO CONVERGENCE).
-C       ON ERROR RETURN, THE ROW IN ERROR.
-C     IERROR IS AN INTEGER VARIABLE.  IT IS SET TO 0 FOR A SUCCESSFUL
-C       SOLUTION (REACHED CONVERGENCE CRITERION), OR NEGATIVE FOR AN
-C       ERROR (INCLUDING FAILURE TO CONVERGE WITHIN THE REQUESTED NUMBER
-C       OF ITERATIONS).
+C     MAXITER GIVES THE REQUESTED NUMBER OF ITERATIONS,
+C       OR IS 0 FOR "NO LIMIT".
+C     ISTATUS IS AN INTEGER VARIABLE, WHICH IS SET TO:
+C       -I IF THERE IS AN ERROR IN THE MATRIX STRUCTURE IN ROW I
+C          (SUCH AS A ZERO ELEMENT ON THE DIAGONAL).
+C        0 IF THE ITERATION FAILED TO REACH THE CONVERGENCE CRITERION
+C          IN ITER ITERATIONS.
+C       +I IF THE ITERATION CONVERGED IN I ITERATIONS.
 C
 C MODIFICATIONS
 C * RETURN LOGICAL VALUE, J. THORNBURG, 13/MAY/85.
 C * ADD CONVERGENCE CRITERIA, J. THORNBURG, 17/MAY/85.
 C * CHANGED CONVERGENCE CRITERIA, J. THORNBURG, 4/AUG/89.
 C * AVOID SKIP RETURNS, J. THORNBURG, 10/SEP/89.
-C * CHANGE FUNCTION BACK TO SUBROUTINE, J. THORNBURG, 2.JUN.2003
+C * CHANGE FUNCTION BACK TO SUBROUTINE, J. THORNBURG, 3.JUN.2003
 C
 C REFERENCE:
 C     D.S.KERSHAW,"THE INCOMPLETE CHOLESKY-CONJUGATE GRADIENT
@@ -74,16 +75,19 @@ C CALCULATE INDICES FOR BREAKING UP TEMPORARY ARRAYS.
       IF (N.LT.0) GO TO 10
 C DO INCOMPLETE LU DECOMPOSITION
       IF (DLU0(NP,IA,JA,A,ITEMP(IC),ITEMP(JC),ITEMP(JCI),RTEMP(IALU),
-     *    ITEMP(ILU),ITEMP(JLU),ITEMP(ID),RTEMP(IR),ISTATUS)) GOTO 20
+     *    ITEMP(ILU),ITEMP(JLU),ITEMP(ID),RTEMP(IR),IERROR)) GOTO 20
 C AND DO CONJUGATE GRADIENT ITERATIONS
 C CALL MODIFIED TO ADD ADJUSTABLE CONVERGENCE CRITERIA EPS
 C - J. THORNBURG, 17/MAY/85.
 10    CALL DNCG0(NP,IA,JA,A,B,X,ITEMP(ILU),ITEMP(JLU),ITEMP(ID),
      *  RTEMP(IALU),RTEMP(IR),RTEMP(IP),RTEMP(IS1),RTEMP(IS2),
-     *  EPS,ITER,ISTATUS)
-      IERROR = 0
+     *  EPS,MAXITER,ITER)
+C ITER IS ACTUAL NUMBER OF ITERATIONS (NEGATIVE IF NO CONVERGENCE)
+      ISTATUS = ITER
+      IF (ITER .LT. 0) ISTATUS = 0
       RETURN
-20    IERROR = -1
+C ERROR RETURN FROM INCOMPLETE LU DECOMPOSITION
+20    ISTATUS = -IERROR
       RETURN
       END
 
@@ -112,7 +116,9 @@ C     ILU AND JLU CORRESPONDS TO IA AND JA BUT FOR ALU.
 C     ID IS AN INTEGER ARRAY DIMENSIONED N.  IT CONTAINS
 C       INDICES TO THE DIAGONAL ELEMENTS OF U.
 C     V IS A REAL SCRATCH VECTOR OF LENGTH N.
-C     IE GIVES THE ROW NUMBER IN ERROR.
+C     IE GIVES THE ROW NUMBER IN ERROR IF AN ERROR OCCURED
+C       (RETURN VALUE .TRUE.), OR IS UNUSED IF ALL IS WELL
+C       (RETURN VALUE .FALSE.).
 C
 C     RETURN VALUE = .FALSE. IF ALL IS WELL, .TRUE. IF ERROR.
 C
diff --git a/src/sparse-matrix/ilucg/ilucg.h b/src/sparse-matrix/ilucg/ilucg.h
index 9d839c9..60cd98b 100644
--- a/src/sparse-matrix/ilucg/ilucg.h
+++ b/src/sparse-matrix/ilucg/ilucg.h
@@ -21,14 +21,14 @@ void CCTK_FCALL
 		     const float B[], float X[],
 		     integer ITEMP[], float RTEMP[],
 		     const float* EPS, const integer* ITER,
-		     integer* ISTATUS, integer* IERROR);
+		     integer* ISTATUS);
 void CCTK_FCALL
   CCTK_FNAME(dilucg)(const integer* N,
 		     const integer IA[], const integer JA[], const double A[],
 		     const double B[], double X[],
 		     integer ITEMP[], double RTEMP[],
 		     const double* EPS, const integer* ITER,
-		     integer* ISTATUS, integer* IERROR);
+		     integer* ISTATUS);
 
 #ifdef __cplusplus
        }	/* extern "C" */
diff --git a/src/sparse-matrix/ilucg/make.code.defn b/src/sparse-matrix/ilucg/make.code.defn
index 035b988..9a3d4ce 100644
--- a/src/sparse-matrix/ilucg/make.code.defn
+++ b/src/sparse-matrix/ilucg/make.code.defn
@@ -1,4 +1,4 @@
-# specification of things to be compiled in this directory
+# Cactus specification of things to be compiled in this directory
 # $Header$
 
 # Source files in this directory
diff --git a/src/sparse-matrix/ilucg/silucg.f77 b/src/sparse-matrix/ilucg/silucg.f77
index 09610e0..fc97c3b 100644
--- a/src/sparse-matrix/ilucg/silucg.f77
+++ b/src/sparse-matrix/ilucg/silucg.f77
@@ -1,4 +1,5 @@
-      SUBROUTINE SILUCG(N,IA,JA,A,
+      SUBROUTINE SILUCG(N,
+     $                  IA,JA,A,
      $                  B,X,
      $                  ITEMP,RTEMP,
      $                  EPS,ITER,
@@ -32,21 +33,21 @@ C       INFINITY-NORM OF THE CURRENT SOLUTION.  HOWEVER, IF EPS
 C       .LT. 0.0, IT IS INTERNALLY SCALED BY THE MACHINE PRECISION,
 C       SO THAT, FOR EXAMPLE, EPS = -256.0 WILL ALLOW THE LAST 8 BITS
 C       OF THE SOLUTION TO BE IN ERROR.       
-C     ITER GIVES THE REQUESTED NUMBER OF ITERATIONS, OR IS 0 FOR "NO LIMIT".
-C     ISTATUS IS AN INTEGER VARIABLE.  FOR NORMAL RETURN, IT GIVES
-C       THE NUMBER OF ITERATIONS DONE (NEGATIVE IS NO CONVERGENCE).
-C       ON ERROR RETURN, THE ROW IN ERROR.
-C     IERROR IS AN INTEGER VARIABLE.  IT IS SET TO 0 FOR A SUCCESSFUL
-C       SOLUTION (REACHED CONVERGENCE CRITERION), OR NEGATIVE FOR AN
-C       ERROR (INCLUDING FAILURE TO CONVERGE WITHIN THE REQUESTED NUMBER
-C       OF ITERATIONS).
+C     MAXITER GIVES THE REQUESTED NUMBER OF ITERATIONS,
+C       OR IS 0 FOR "NO LIMIT".
+C     ISTATUS IS AN INTEGER VARIABLE, WHICH IS SET TO:
+C       -I IF THERE IS AN ERROR IN THE MATRIX STRUCTURE IN ROW I
+C          (SUCH AS A ZERO ELEMENT ON THE DIAGONAL).
+C        0 IF THE ITERATION FAILED TO REACH THE CONVERGENCE CRITERION
+C          IN ITER ITERATIONS.
+C       +I IF THE ITERATION CONVERGED IN I ITERATIONS.
 C
 C MODIFICATIONS
 C * RETURN LOGICAL VALUE, J. THORNBURG, 13/MAY/85.
 C * ADD CONVERGENCE CRITERIA, J. THORNBURG, 17/MAY/85.
 C * CHANGED CONVERGENCE CRITERIA, J. THORNBURG, 4/AUG/89.
 C * AVOID SKIP RETURNS, J. THORNBURG, 10/SEP/89.
-C * CHANGE FUNCTION BACK TO SUBROUTINE, J. THORNBURG, 2.JUN.2003
+C * CHANGE FUNCTION BACK TO SUBROUTINE, J. THORNBURG, 3.JUN.2003
 C
 C REFERENCE:
 C     D.S.KERSHAW,"THE INCOMPLETE CHOLESKY-CONJUGATE GRADIENT
@@ -74,16 +75,19 @@ C CALCULATE INDICES FOR BREAKING UP TEMPORARY ARRAYS.
       IF (N.LT.0) GO TO 10
 C DO INCOMPLETE LU DECOMPOSITION
       IF (SLU0(NP,IA,JA,A,ITEMP(IC),ITEMP(JC),ITEMP(JCI),RTEMP(IALU),
-     *    ITEMP(ILU),ITEMP(JLU),ITEMP(ID),RTEMP(IR),ISTATUS)) GOTO 20
+     *    ITEMP(ILU),ITEMP(JLU),ITEMP(ID),RTEMP(IR),IERROR)) GOTO 20
 C AND DO CONJUGATE GRADIENT ITERATIONS
 C CALL MODIFIED TO ADD ADJUSTABLE CONVERGENCE CRITERIA EPS
 C - J. THORNBURG, 17/MAY/85.
 10    CALL SNCG0(NP,IA,JA,A,B,X,ITEMP(ILU),ITEMP(JLU),ITEMP(ID),
      *  RTEMP(IALU),RTEMP(IR),RTEMP(IP),RTEMP(IS1),RTEMP(IS2),
-     *  EPS,ITER,ISTATUS)
-      IERROR = 0
+     *  EPS,MAXITER,ITER)
+C ITER IS ACTUAL NUMBER OF ITERATIONS (NEGATIVE IF NO CONVERGENCE)
+      ISTATUS = ITER
+      IF (ITER .LT. 0) ISTATUS = 0
       RETURN
-20    IERROR = -1
+C ERROR RETURN FROM INCOMPLETE LU DECOMPOSITION
+20    ISTATUS = -IERROR
       RETURN
       END
 
@@ -112,7 +116,9 @@ C     ILU AND JLU CORRESPONDS TO IA AND JA BUT FOR ALU.
 C     ID IS AN INTEGER ARRAY DIMENSIONED N.  IT CONTAINS
 C       INDICES TO THE DIAGONAL ELEMENTS OF U.
 C     V IS A REAL SCRATCH VECTOR OF LENGTH N.
-C     IE GIVES THE ROW NUMBER IN ERROR.
+C     IE GIVES THE ROW NUMBER IN ERROR IF AN ERROR OCCURED
+C       (RETURN VALUE .TRUE.), OR IS UNUSED IF ALL IS WELL
+C       (RETURN VALUE .FALSE.).
 C
 C     RETURN VALUE = .FALSE. IF ALL IS WELL, .TRUE. IF ERROR.
 C