calculation method changes from pardiso to picos

Question

hi everyone i'm modeling a large number of volume piles and as a result the program changes from pardiso to picos for lack of memory (8 gb) and then picos gives slow convergence ... i tried one core iterative method but it didn't help either is there anyway to force the solver type as pardiso even it'd take longer time taking into account the lack of memory? ... and if not how much memory are we talking about to use pardiso for such big models ? 
 thanks in advance

dep25 niiosp · Answer

abdarhman dbass said: is there anyway to force the solver type 
 There is no way to force the solver type to stay Pardiso. 
 Pardiso uses somewhere near 4-5 times more than picos, but it is not a rule. 
 You have two options: 1) upgrade memory; 
 2) find mesh with fewer elements. 
 abdarhman dbass said: how much memory are we talking about 
 It depends on dofs and parallel tasks. There is no limit.

Stefanos Papavasileiou · Answer

Dear Abdarhman, 
 Indeed, as mentioned by the other comments from dep25 niiosp, PLAXIS automatically checks the number of the degrees of freedom to be solved and if Pardiso would require many GB of memory it switches to Picos solver to be more efficient. 
 There is no generic rule as the number of elements, the type of analysis, the boundary conditions can affect the total number o f the degrees of freedom to be solved, so there is no simple answer to that. 
 Note that slow convergence can be an issue of many things in PLAXIS. I would first start by checking all the material parameters and then some of the following Output plots to indicate what the problem might be: 
 
 deformed mesh 
 total displacements (shaded plot) 
 incremental displacement (shaded plot and/or arrows) 
 total deviatoric strain (shaded plot) 
 incremental deviatoric strains (shaded plot) 
 plastic points 
 when applicable: excess pore pressures (pexcess) 
 
 A combination of these plots will usually give insight into what is happening.