2022-07-13 Niall Bootland Version 5.3.2. State METIS 5 incompatability in documentation. 2022-01-24 Jaroslav Fowkes Version 5.3.1. Standardise internal C interface names. 2021-06-01 Iain Duff and Jaroslav Fowkes Version 5.3.0. Includes several changes: * New C interface to HSL_MA57 with all subroutines implemented. * Subroutine nflag that identifies nodes holding sparse rhs entries for ma57_sparse_lsolve corrected to search all entries of sparse rhs (an exit changed to cycle). * Spec sheet changed to indicate that the sparse rhs lsolve option can only be used if the matrix is positive definite. The subroutine ma57_sparse_lsolve checks that this is so and returns an error if the factorization has any two-by-two or negative pivots. * The spec sheet also now says that version 4 of METIS must be used. 2013-08-02 Iain Duff Version 5.2.0. Correction made to space allocated for internal array in subroutine MA57LF/FD. 2013-04-18 Iain Duff Version 5.1.0. Fix innocuous potential undefined variable bug following related problems in HSL_ME57 when extending array sizes. 2013-03-21 Iain Duff Version 5.0.0. Includes several new facilities: viz. * Returns Fredholm vector in singular inconsistent case * Multiplies vector by L or L transpose * Solves for sparse rhs * Returns factors in standard format 2010-08-06 Version 4.2.1. Fix spec sheet to read "HSL_ZD11" rather than "ZD11" 2010-04-01 Version 4.2.0. Component ainfo%ordering added and assigned return value of info(36) from MA57AD to indicate ordering actually used. The message in the error return from MA57_FACTORIZE corrected to show return is from FACTORIZE rather than ANALYSE. The components of info parameters are given default values. 2007-09-20 Version 4.1.0. Code tidied to interface with Version 3.2.0 of MA57 .. an added control parameter rank_deficient allows the option of dropping blocks of small entries during the factorization. 2006-12-04 Version 4.0.0. Pointer arrays replaced by allocatables. 2006-02-28 Version 3.2.0. To avoid memory leaks, ma57_initialize and ma57_finalize leave pointer component null instead having zero size. 2005-06-14 Version 3.1.0. The space needed for ma57bd now recomputed in the factorize entry so that the user can change the value of control%pivoting and control%scaling between calls to analyse and factorize. cond2, berr, berr2, error added to sinfo to return condition number for category 2 equations, backward error, and forward error for category 2 equations as in Arioli, Demmel, and Duff (1989). control%convergence added so that cntl(3) can be set for ma57dd call. Small change to write statement for failure in finalize. 2005-03-07 Version 3.0.0. Mostly a large set of changes inherited from the MA57 (F77) code. See the header for MA57A/AD for details of these. Changes within the F90 code include: change of default for CONTROL%ORDERING, introduction of new component AINFO%ORDERING, correction of error in deallocate statement in solve1 and solve2, and changes to diagnostic output format. 2004-11-01 Version 2.0.1. Defaults changed, since they are taken from MA57. 2004-07-31 Version 2.0.0 established at HSL 2004 release. 2004-07-20 Several changes incorporated for HSL 2004 code. Removed unused INT,ABS from MA57U/UD INFO(32), INFO(33), and INFO(34) added * INFO(32): number of zeros in the triangle of the factors * INFO(33): number of zeros in the rectangle of the factors * INFO(34): number of zero columns in rectangle of the factors Static pivoting available (controlled by CNTL(4)) 2004-07-12 Version 1.0.0. Version numbering added. 2004-05-24 Statement functions in MA57U/UD replaced by in-line code. 2002-05-10 Factors of data type ma57_factors made intent(in) in solves 2001-12-19 Optional parameter added to enquire routine to return perturbation factors%pivoting added to hold pivoting option la increased when Schnabel-Eskow option invoked sinfo%more removed. 2000-11-01 Entries in IW initialized to zero in MA57O/OD to avoid copy of unassigned variables by MA57E/ED. AINPUT and IINPUT reset in call to MA57E/ED. sinfo%more initialized to 0. MA27 changed to MA57 in allocation error return. calls to MC41 changed to MC71 calls. 1999-09-13 Original version.