tdetermine grid and distance corrections for periodic boundaries during contact search - Granular.jl - Julia package for granular dynamics simulation
(HTM) git clone git://src.adamsgaard.dk/Granular.jl
(DIR) Log
(DIR) Files
(DIR) Refs
(DIR) README
(DIR) LICENSE
---
(DIR) commit 8e3305398e56df7d14cc2fe448838530cdb6532e
(DIR) parent 06506b845e2f703b7c90d99aea71837b0b53ac93
(HTM) Author: Anders Damsgaard <andersd@riseup.net>
Date: Wed, 1 Nov 2017 15:48:10 -0400
determine grid and distance corrections for periodic boundaries during contact search
Diffstat:
M src/contact_search.jl | 43 ++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 4 deletions(-)
---
(DIR) diff --git a/src/contact_search.jl b/src/contact_search.jl
t@@ -91,6 +91,10 @@ Perform an O(n*log(n)) cell-based contact search between all grains in the
"""
function findContactsInGrid!(simulation::Simulation, grid::Any)
+ distance_modifier = [0., 0.]
+ i_corrected = 0
+ j_corrected = 0
+
for idx_i = 1:length(simulation.grains)
if typeof(grid) == Ocean
t@@ -98,19 +102,50 @@ function findContactsInGrid!(simulation::Simulation, grid::Any)
elseif typeof(grid) == Atmosphere
grid_pos = simulation.grains[idx_i].atmosphere_grid_pos
else
- error("grid type not understood")
+ error("Grid type not understood")
end
nx, ny = size(grid.xh)
for i=(grid_pos[1] - 1):(grid_pos[1] + 1)
for j=(grid_pos[2] - 1):(grid_pos[2] + 1)
- # only check for contacts within grid boundaries
+ # i and j are not corrected for periodic boundaries
+ i_corrected = i
+ j_corrected = j
+
+ # vector for correcting inter-particle distance in case of
+ # boundary periodicity
+ distance_modifier .= [0., 0.]
+
+ # only check for contacts within grid boundaries, and wrap
+ # around if they are periodic
if i < 1 || i > nx || j < 1 || j > ny
- continue
+
+ if i < 1 && grid.bc_west == 1 # periodic -x
+ distance_modifier[1] = grid.xq[end] - grid.xq[1]
+ i_corrected = nx
+ elseif i > nx && grid.bc_east == 1 # periodic +x
+ distance_modifier[1] = -(grid.xq[end] - grid.xq[1])
+ i_corrected = 1
+ end
+
+ if j < 1 && grid.bc_south == 1 # periodic -y
+ distance_modifier[2] = grid.yq[end] - grid.yq[1]
+ j_corrected = ny
+ elseif j > ny && grid.bc_north == 1 # periodic +y
+ distance_modifier[2] = -(grid.yq[end] - grid.yq[1])
+ j_corrected = 1
+ end
+
+ # skip iteration if target still falls outside grid after
+ # periodicity correction
+ if i_corrected < 1 || i_corrected > nx ||
+ j_corrected < 1 || j_corrected > ny
+ continue
+ end
end
- @inbounds for idx_j in grid.grain_list[i, j]
+ @inbounds for idx_j in grid.grain_list[i_corrected, j_corrected]
checkAndAddContact!(simulation, idx_i, idx_j)
end
end