2013-04-10  Jennifer Scott
Version 1.3.0. Fix some undefined variable errors found by nagfor.

2009-03-06
Version 1.2.0. To allow repeated calls of MA42_FACTORIZE, 
do not deallocate data%LAST when forward elimination pass is complete.

2005-01-18
Version 1.1.0. In MA42N/ND changed
IF (NMAXE.EQ.1 .OR. LAST(MFR).GE.0) THEN
into two separate tests (problem if NMAXE = 1 and system
is singular, MFR may be too large)

2004-07-12
Version 1.0.0. Version numbering added.

2001-01-??
Edited MA42_FILES to avoid unnecessary copying on INQUIRE

2001-01-??
Added extra message if -16 returned and LENBUF not present.

2001-01-??
Error flag -25 set if a routine is called after an
error has been returned.

2001-01-??
I have added some pointer assignments (see BUFU_TEMP etc).
This is because some compliers produce very
inefficient code when pointer components of a derived data type are
used in a subroutine call and when array sections are used.
When we replace pointer components of the derived data type
by allocatable arrays (we plan to do this when allowed),
we will need to get rid of these pointer assignments.

1999-11-29
Error in call to MA42H from MA42N when
KPRE>0 or LFRE>0.
Also, changed second dimension of FA in MA42G from NFRONT
to * (NFRONT causes error when MA42G called from MA42N
when KPRE>0 or LFRE>0).

1999-08-06
Error in MA42D/DD. If direct access files not used
then JFLAG not set so at end of subroutine jump
to return (in MA42E/ED jump already there.)

1999-05-20
Error found in MA42D/DD.
Replace
 IBUFR(DIMIBF-IRECD+1:DIMIBF) = IBUFR(IR2+1:IR2+IRECD)
by
 DO I = IRECD,1,-1
    IBUFR(DIMIBF-IRECD+I) = IBUFR(IR2+I)
 END DO
and
 BUFR(DIMBUF-IPNT+1:DIMBUF) = BUFR(JR2+1:JR2+IPNT)
by
 DO I = IPNT,1,-1
    BUFR(DIMBUF-IPNT+I) = BUFR(JR2+I)
 END DO

1999-04-28
Error in flop count for static condensation variables
corrected. In MA42O
        IF (NMAXE.GT.1) OPS = OPS + REAL(NUMPIV* (NVAR-1)* (NVAR-1)*2)
changed to
        IF (NMAXE.GT.1) THEN
           DO 360 J = 1,NUMPIV
               OPS = OPS + REAL((NVAR-J)* (MVAR-J)*2)
  360      CONTINUE
        END IF
NOTE: has no effect for equation entry (since NUMPIV=1)

1998-12-18
In MA42F/FD changed
  INFO(10) = MKEY(1)
  INFO(11) = MKEY(2)
  INFO(12) = MKEY(3)
to
  INFO(10) = MAX(1,MKEY(1))
  INFO(11) = MAX(1,MKEY(2)) ... this only if L factored stored
  INFO(12) = MAX(1,MKEY(3))
(since otherwise can get data%BUFFERS equal to zero when error
-17 return ...  no use for resetting LENFLE)

1998-10-22
Modified to exploit the zeros within the
frontal matrix. Added parameter data%EXPLOIT to control this.
Also, extra parameter data%PIVOT_SIZE in MA42F allows us to wait
until sufficiently many variables can be eliminated at once
(as in cache paper). data%PIVOT_SIZE ALSO USED IN  MA42_SYMBOLIC.
We have set this parameter to 1 (as this is equivalent
to HSL12 but we would recommend using a larger value eg 16)

1997-09-04
In MA42_SYMBOLIC, if called from within MA42B
(because frontsize too small), use INFO values to
initialise data%FILE_BOUND and allow updated lower bounds
on the filesizes to be returned to the user.

1997-03-14
In MA42F added a test so that MA42N is only
called if some variables have become fully since
the assembly of the most recent elt/equ.

1997-01-20
In MA42_FACTORIZE, avoid zeroing the solution vector X
if the number of variables in the problem is
equal to the largest integer used to index a variable
(i.e if NDF = data%private%INFO(3)).

1996-11-11
After each call to MA42D and MA42E, check
the error flag and write error message if appropriate.

1994-11-30
Original version.