| Changes from version 5.1 to version 5.5Main features and changes to v5.5 compared to v5.1
					Why a jump from version numbers 5.1 to 5.5 ? This is done to indicate that this
					is more than just another update. The solver engine was revised and optimised in such
					a way that performance has improved considerably. Numerical stability is also better resulting
					in more models that can be solved. The LUSOL bfp is now also the default. In the past, the
					etaPFI bfp package was the default, but for larger models this leads faster to numerical
					instabilities and performance problems. Overall, the v5.5 code is faster and more robust than v5.1. This robustness is for
					example proven by the fact that many more models can now be solved even without
					scaling. The API hasn't changed very much. There are a couple of new routines and one routine has an extra argument.
					   Some constants got new values. 
					    
							Fundamental internal change to the solver engine resulting in better performance
							and numerical stability. Both the LP solver and the B&B solvers are enhanced.
							Optimised MILP branch truncation, with reduced cost fixing.
							LUSOL bfp is now the default.
							Presolve is improved in functionality and performance.
							Better handling of degeneracy, with more options.
							Store and read options from a file make it easier to set options.See read_params and write_params
							Partial pricing for the primal simplex now works.
							Full support for xli_ZIMPL v2.0.3.
							The objective function is no longer stored as part of the constraint matrix.
							Dual-long step code is in place, but not fully activated yet.
							General code cleanup.
							Added OBJSENSE and OBJNAME headers in the free MPS format (See MPS file format).
							The MathProg xli driver has now the ability to generate a model.
							New API routines, see further. Note the store and read options from a file. This can be a very nice new feature.
					lp_solve has a lot of options and with this new addition it is much easier to set these
					options. People can start looking for the best options that work for their models very easily and
					it could help to find even better default options. Changed API calls
						
							get_basis
							
								
									Return value is now unsigned char instead of void
								
							get_total_iter
							
								
									Return value is now long long instead of long
								
							get_total_nodes
							
								
									Return value is now long long instead of long
								
							put_abortfunc
							
								
									Argument newctrlc is now from type lphandle_intfunc instead of ctrlcfunc
								
							put_logfunc
							
								
									Argument newlog is now from type lphandlestr_func instead of logfunc
								
							put_msgfunc
							
								
									Argument newmsg is now from type lphandleint_func instead of msgfunc
								
							set_anti_degen
							
								
									New constants are added: ANTIDEGEN_RHSPERTURB, ANTIDEGEN_BOUNDFLIP
								
							set_basiscrash
							
								
									New constant added: CRASH_LEASTDEGENERATE
								
							set_bb_rule
							
							    Constant NODE_GUBMODE was not documented.
									New constants are added: NODE_RCOSTFIXING, NODE_STRONGINIT
								
							set_improve (!)
							
								
									Constants are deleted: IMPROVE_FTRAN, IMPROVE_BTRAN, IMPROVE_SOLVE, IMPROVE_INVERSE
								
									New constants are added: IMPROVE_SOLUTION, IMPROVE_DUALFEAS, IMPROVE_THETAGAP, IMPROVE_BBSIMPLEX
								
							set_pivoting (!)
							
								
									Constants are deleted: PRICE_AUTOPARTIALCOLS, PRICE_AUTOPARTIALROWS, PRICE_AUTOMULTICOLS, PRICE_AUTOMULTIROWS
								
									New constants added: PRICE_AUTOPARTIAL, PRICE_AUTOMULTIPLE, PRICE_HARRISTWOPASS, PRICE_TRUENORMINIT
								
							set_presolve (!)
							
								
									There is a new third argument: maxloops
								
									PRESOLVE_DUALS has a new value. Before it was 128, now it is 524288
								
									PRESOLVE_SENSDUALS has a new value. Before it was 256, now it is 1048576
								
									New constants are added: PRESOLVE_KNAPSACK, PRESOLVE_ELIMEQ2, PRESOLVE_IMPLIEDFREE, PRESOLVE_REDUCEGCD, PRESOLVE_PROBEFIX, PRESOLVE_PROBEREDUCE, PRESOLVE_ROWDOMINATE, PRESOLVE_COLDOMINATE, PRESOLVE_MERGEROWS, PRESOLVE_IMPLIEDSLK, PRESOLVE_COLFIXDUAL, PRESOLVE_BOUNDS
								 New API callsRemoved API calls |