tOptimize Poisson-disk sampling algorithm, fix active list maintenance - Granular.jl - Julia package for granular dynamics simulation
(HTM) git clone git://src.adamsgaard.dk/Granular.jl
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---
(DIR) commit 7b7df1fcc13b749f31cf95cb962a2c80b5cc9134
(DIR) parent 62b30ca4668b7809b1664cb98c0fb70c9c15e410
(HTM) Author: Anders Damsgaard <andersd@riseup.net>
Date: Fri, 22 Dec 2017 11:31:32 -0500
Optimize Poisson-disk sampling algorithm, fix active list maintenance
Diffstat:
M src/packing.jl | 88 +++++++++++++++++++++++--------
1 file changed, 66 insertions(+), 22 deletions(-)
---
(DIR) diff --git a/src/packing.jl b/src/packing.jl
t@@ -117,7 +117,7 @@ function irregularPacking!(simulation::Simulation;
radius_min::Real=.1,
sample_limit::Integer=30,
padding_factor::Real=2.,
- progressive_downwards_radius_search::Bool=false,
+ binary_radius_search::Bool=false,
thickness::Real=1.,
seed::Integer=1,
plot_during_packing::Bool=false,
t@@ -170,22 +170,25 @@ function irregularPacking!(simulation::Simulation;
while !isempty(active_list)
- i = rand(1:length(active_list))
+ # Draw a random grain from the list of active grains
+ i = active_list[rand(1:length(active_list))]
x_active = simulation.grains[i].lin_pos
r_active = simulation.grains[i].contact_radius
+ # Did the algoritm find a neighbor to the current active grain `i`?
neighbor_found = false
for j=1:sample_limit
- if progressive_downwards_radius_search
+ # Generate a candidate point
+ if binary_radius_search
# Generate a point positioned at r_active + radius_max from the
# position x_active.
T = generateRandomDirection()
r_candidate = radius_max
- x_candidate = getPositionFromPoint(x_active, T,
- r_active + r_candidate)
+ x_candidate = getPositionDistancedFromPoint(T, x_active,
+ r_active + r_candidate)
else
if j <= 2
x_candidate, r_candidate = generateNeighboringPoint(
t@@ -203,43 +206,84 @@ function irregularPacking!(simulation::Simulation;
end
end
-
+ # Make sure that the point is within the current grid cell
if !(isPointInGrid(grid, x_candidate))
continue # skip this candidate
end
-
- if progressive_downwards_radius_search
- while no_overlaps_found == false
- error("not yet implemented")
+ # If the binary_radius_search is selected, try to adjust the radius
+ # to a value as large as possible
+ if binary_radius_search
+
+ radius_not_found = true
+
+ # first test the maximum radius. If unsuccessful, iteratively
+ # find the optimal radius using binary searches
+ if !checkForContacts(simulation, grid, x_candidate, r_candidate)
+
+ # 1. Set L to min and R to max of sampling range
+ r_L = radius_min
+ r_R = radius_max
+
+ # size of radius sampling step
+ dr = (r_R - r_L)/25.
+
+ while radius_not_found
+
+ # 2. If L > R, the search terminates as unsuccessful
+ if r_L > r_R
+ radius_not_found = false
+ break
+ end
+
+ # 3. Set r to the middle of the current range
+ r_candidate = (r_L + r_R)/2.0
+ x_candidate = getPositionDistancedFromPoint(T, x_active,
+ r_active + r_candidate)
+
+ # 4. If r < target, set L to r+dr and go to step 2
+ if checkForContacts(simulation, grid, x_candidate,
+ r_candidate)
+ r_L = r_candidate + dr
+
+ else # 5. If r > target, set R to r-dr and go to step 2
+ r_R = r_candidate - dr
+ end
+ end
end
- else
- no_overlaps_found = checkForContacts(simulation, grid,
- x_candidate,
- r_candidate)
+
end
- # if the grain candidate doesn't overlap with any other grains, add
- # it to the active list
- if no_overlaps_found
+ # if the grain candidate doesn't overlap with any other grains,
+ # add it and mark it as active
+ if checkForContacts(simulation, grid, x_candidate, r_candidate)
+ #println("Added grain from parent $i")
addGrainCylindrical!(simulation, x_candidate, r_candidate,
thickness, verbose=false)
sortGrainsInGrid!(simulation, grid)
push!(active_list, length(simulation.grains))
- neighbor_found = true
+ break
+ end
+
+ if j == sample_limit
+ # If no neighbors were found, delete the grain `i` from the list
+ # of active grains
+ filter!(f->f≠i, active_list)
end
end
- if !neighbor_found
- deleteat!(active_list, i)
+ if verbose
+ println("Active points: $(length(active_list))")
+ #println(active_list)
end
- println("Active points: $(length(active_list))")
if plot_during_packing
n += 1
filepostfix = @sprintf("packing.%05d.png", n)
plotGrains(simulation, filetype=filepostfix, show_figure=false)
end
- end
+
+ end # end while !isempty(active_list)
+
if verbose
info("Generated $(length(simulation.grains) - np_init) points")
end