[Coin-discuss] two phase algorithm with algo vars in BCP problem correction

[jvielma at entelchile.net]

	It seems that problem with the 2 phase algorithm doesn't have anything to do with what I wrote on my last email. I just got confused with BCP_lp_node::indexed_pricing.get_status()  thinking that it
only controled pricing status for index variables when it does for both index and algo. vars.

	So lets see if I got the procedure for implementing the 2 phase ( or n phase for that mater )algorithm.

	- I should use BCP_tm_user::init_new_phase to tell BCP what to do with fathomable nodes in each phase. For example for a tipical II phases I should set BCP_DoNotGenerateColumns_Send for phase 0 and 
BCP_GenerateColumns for phase 1.
	
	- I am responsible for not generating columns on a particular phase ( in the example phase 0 ) because pricing_status in BCP_tm_user::create_root should be set to something other than BCP_PriceNothing  for all phases

	And this works both for algo and index variables.

	I still have to try using the PriceInRootBeforePhase2 and TrimTreeBeforeNewPhase options.

	If the above is correct then the problem I had with two phases was that I got the following 

message just after starting phase 1:

	"Unexpected BCP_Msg_LpStatistics message in BCP_tm_process_message"

	It seems that BCP_tm_notify_about_new_phase(p) sends a BCP_Msg_NextPhaseStarts message to the 
BCP_lp which sends back to BCP_tm a BCP_Msg_LpStatistics message which trows an exeption.

	Did I forget to some parameter or is this just an unexpected behaviour?

	I still have some trouble with fathoming procedures specially when I don't have a good bound for a not totally priced LP, but I will look at it in detail before posting.


Juan Pablo Vielma,