Dear Matt, I just update the code. Greatly improved for the new one. For the bulk water, now it has the nearly same speed as verion of Jan. 10. Then I test a more large system, which includes surface. The speed is quite greatly improved, for one OT step, the quite new one is 7.45 s the one Jan. 10 is 7.22 s the version this morning is 8.05 s The RS informations are as follows: The quite new one: _____________________________________________________________________ PW_GRID: Information for grid number 4 PW_GRID: Grid distributed over 32 processors PW_GRID: Real space group dimensions 32 1 PW_GRID: Cutoff [a.u.] 2.5 PW_GRID: Bounds 1 -9 8 Points: 18 PW_GRID: Bounds 2 -12 11 Points: 24 PW_GRID: Bounds 3 -36 35 Points: 72 PW_GRID: Volume element (a.u.^3) 2.131 Volume (a.u.^3) 66281.4981 PW_GRID: Grid span FULLSPACE PW_GRID: Distribution Average Max Min PW_GRID: G-Vectors 972.0 1728 864 PW_GRID: G-Rays 54.0 96 48 PW_GRID: Real Space Points 972.0 1728 0 RS_GRID: Information for grid number 1 RS_GRID: Bounds 1 -72 71 Points: 144 RS_GRID: Bounds 2 -96 95 Points: 192 RS_GRID: Bounds 3 -288 287 Points: 576 RS_GRID: Real space distribution over 4 groups RS_GRID: Real space distribution along direction 2 RS_GRID: Border size 23 RS_GRID: Real space distribution over 8 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 23 RS_GRID: Distribution Average Max Min RS_GRID: Planes 94.0 94 94 RS_GRID: Distribution Average Max Min RS_GRID: Planes 118.0 118 118 RS_GRID: Information for grid number 2 RS_GRID: Bounds 1 -36 35 Points: 72 RS_GRID: Bounds 2 -48 47 Points: 96 RS_GRID: Bounds 3 -144 143 Points: 288 RS_GRID: Real space distribution over 32 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 25 RS_GRID: Distribution Average Max Min RS_GRID: Planes 59.0 59 59 RS_GRID: Information for grid number 3 RS_GRID: Bounds 1 -18 17 Points: 36 RS_GRID: Bounds 2 -24 23 Points: 48 RS_GRID: Bounds 3 -72 71 Points: 144 RS_GRID: Real space fully replicated RS_GRID: Group size 1 RS_GRID: Information for grid number 4 RS_GRID: Bounds 1 -9 8 Points: 18 RS_GRID: Bounds 2 -12 11 Points: 24 RS_GRID: Bounds 3 -36 35 Points: 72 RS_GRID: Real space fully replicated RS_GRID: Group size 1 ___________________________________________________________________ The version in this morning, ____________________________________________________________________ PW_GRID: Information for grid number 4 PW_GRID: Grid distributed over 32 processors PW_GRID: Real space group dimensions 32 1 PW_GRID: Cutoff [a.u.] 2.5 PW_GRID: Bounds 1 -9 8 Points: 18 PW_GRID: Bounds 2 -12 11 Points: 24 PW_GRID: Bounds 3 -36 35 Points: 72 PW_GRID: Volume element (a.u.^3) 2.131 Volume (a.u.^3) 66281.4981 PW_GRID: Grid span FULLSPACE PW_GRID: Distribution Average Max Min PW_GRID: G-Vectors 972.0 1728 864 PW_GRID: G-Rays 54.0 96 48 PW_GRID: Real Space Points 972.0 1728 0 RS_GRID: Information for grid number 1 RS_GRID: Bounds 1 -72 71 Points: 144 RS_GRID: Bounds 2 -96 95 Points: 192 RS_GRID: Bounds 3 -288 287 Points: 576 RS_GRID: Real space distribution over 4 groups RS_GRID: Real space distribution along direction 2 RS_GRID: Border size 23 RS_GRID: Real space distribution over 8 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 23 RS_GRID: Distribution Average Max Min RS_GRID: Planes 94.0 94 94 RS_GRID: Distribution Average Max Min RS_GRID: Planes 118.0 118 118 RS_GRID: Information for grid number 2 RS_GRID: Bounds 1 -36 35 Points: 72 RS_GRID: Bounds 2 -48 47 Points: 96 RS_GRID: Bounds 3 -144 143 Points: 288 RS_GRID: Real space distribution over 32 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 25 RS_GRID: Distribution Average Max Min RS_GRID: Planes 59.0 59 59 RS_GRID: Information for grid number 3 RS_GRID: Bounds 1 -18 17 Points: 36 RS_GRID: Bounds 2 -24 23 Points: 48 RS_GRID: Bounds 3 -72 71 Points: 144 RS_GRID: Real space distribution over 32 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 24 RS_GRID: Distribution Average Max Min RS_GRID: Planes 52.5 53 52 RS_GRID: Information for grid number 4 RS_GRID: Bounds 1 -9 8 Points: 18 RS_GRID: Bounds 2 -12 11 Points: 24 RS_GRID: Bounds 3 -36 35 Points: 72 RS_GRID: Real space distribution over 32 groups RS_GRID: Real space distribution along direction 3 RS_GRID: Border size 16 RS_GRID: Distribution Average Max Min RS_GRID: Planes 34.3 35 34 Best Regards, Limin <div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">