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```@meta | ||
EditURL = "../../../tutorials/Tutorial_Chmy_MPI.jl" | ||
``` | ||
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# Create an initial model setup for Chmy and run it in parallel | ||
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## Aim | ||
In this tutorial, your will learn how to use [Chmy](https://github.com/PTsolvers/Chmy.jl) to perform a 2D diffusion simulation | ||
on one or multiple CPU's or GPU's. | ||
`Chmy` is a package that allows you to specify grids and fields and create finite difference simulations | ||
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## 1. Load Chmy and required packages | ||
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```julia | ||
using Chmy, Chmy.Architectures, Chmy.Grids, Chmy.Fields, Chmy.BoundaryConditions, Chmy.GridOperators, Chmy.KernelLaunch | ||
using KernelAbstractions | ||
using Printf | ||
using CairoMakie | ||
using GeophysicalModelGenerator | ||
``` | ||
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In case you want to use GPU's, you need to sort out whether you have AMD or NVIDIA GPU's | ||
and load the package accordingly: | ||
using AMDGPU | ||
AMDGPU.allowscalar(false) | ||
using CUDA | ||
CUDA.allowscalar(false) | ||
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To run this in parallel you need to load this: | ||
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```julia | ||
using Chmy.Distributed | ||
using MPI | ||
MPI.Init() | ||
``` | ||
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## 2. Define computational routines | ||
You need to specify compute kernel for the gradients: | ||
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```julia | ||
@kernel inbounds = true function compute_q!(q, C, χ, g::StructuredGrid, O) | ||
I = @index(Global, NTuple) | ||
I = I + O | ||
q.x[I...] = -χ * ∂x(C, g, I...) | ||
q.y[I...] = -χ * ∂y(C, g, I...) | ||
end | ||
``` | ||
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You need to specify compute kernel to update the concentration | ||
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```julia | ||
@kernel inbounds = true function update_C!(C, q, Δt, g::StructuredGrid, O) | ||
I = @index(Global, NTuple) | ||
I = I + O | ||
C[I...] -= Δt * divg(q, g, I...) | ||
end | ||
``` | ||
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And a main function is required: | ||
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```julia | ||
@views function main(backend=CPU(); nxy_l=(126, 126)) | ||
arch = Arch(backend, MPI.COMM_WORLD, (0, 0)) | ||
topo = topology(arch) | ||
me = global_rank(topo) | ||
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# geometry | ||
dims_l = nxy_l | ||
dims_g = dims_l .* dims(topo) | ||
grid = UniformGrid(arch; origin=(-2, -2), extent=(4, 4), dims=dims_g) | ||
launch = Launcher(arch, grid, outer_width=(16, 8)) | ||
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##@info "mpi" me grid | ||
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nx, ny = dims_g | ||
# physics | ||
χ = 1.0 | ||
# numerics | ||
Δt = minimum(spacing(grid))^2 / χ / ndims(grid) / 2.1 | ||
# allocate fields | ||
C = Field(backend, grid, Center()) | ||
P = Field(backend, grid, Center(), Int32) # phases | ||
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q = VectorField(backend, grid) | ||
C_v = (me==0) ? KernelAbstractions.zeros(CPU(), Float64, size(interior(C)) .* dims(topo)) : nothing | ||
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# Use the `GeophysicalModelGenerator` to set the initial conditions. Note that | ||
# you have to call this for a `Phases` and a `Temp` grid, which we call `C` here. | ||
add_box!(P,C,grid, xlim=(-1.0,1.0), zlim=(-1.0,1.0), phase=ConstantPhase(4), T=ConstantTemp(400)) | ||
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# set BC's and updates the halo: | ||
bc!(arch, grid, C => Neumann(); exchange=C) | ||
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# visualisation | ||
fig = Figure(; size=(400, 320)) | ||
ax = Axis(fig[1, 1]; aspect=DataAspect(), xlabel="x", ylabel="y", title="it = 0") | ||
plt = heatmap!(ax, centers(grid)..., interior(C) |> Array; colormap=:turbo) | ||
Colorbar(fig[1, 2], plt) | ||
# action | ||
nt = 100 | ||
for it in 1:nt | ||
(me==0) && @printf("it = %d/%d \n", it, nt) | ||
launch(arch, grid, compute_q! => (q, C, χ, grid)) | ||
launch(arch, grid, update_C! => (C, q, Δt, grid); bc=batch(grid, C => Neumann(); exchange=C)) | ||
end | ||
KernelAbstractions.synchronize(backend) | ||
gather!(arch, C_v, C) | ||
if me == 0 | ||
fig = Figure(; size=(400, 320)) | ||
ax = Axis(fig[1, 1]; aspect=DataAspect(), xlabel="x", ylabel="y", title="it = 0") | ||
plt = heatmap!(ax, C_v; colormap=:turbo) # how to get the global grid for axes? | ||
Colorbar(fig[1, 2], plt) | ||
save("out_gather_$nx.png", fig) | ||
end | ||
return | ||
end | ||
``` | ||
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In the code above, the part that calls `GMG` is: | ||
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```julia | ||
add_box!(P,C,grid, xlim=(-1.0,1.0), zlim=(-1.0,1.0), phase=ConstantPhase(4), T=ConstantTemp(400)) | ||
``` | ||
which works just like any of the other GMG function. | ||
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## 3. Run the simulation on one CPU machine or GPU card: | ||
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Running the code on the CPU is done with this: | ||
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```julia | ||
n = 128 | ||
main(; nxy_l=(n, n) .- 2) | ||
``` | ||
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If you instead want to run this on AMD or NVIDIA GPU's do this: | ||
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```julia | ||
# main(ROCBackend(); nxy_l=(n, n) .- 2) | ||
# main(CUDABackend(); nxy_l=(n, n) .- 2) | ||
``` | ||
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And we need to finalize the simulation with | ||
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```julia | ||
MPI.Finalize() | ||
``` | ||
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## 4. Run the simulation on an MPI-parallel machine | ||
If you want to run this on multiple cores, you will need to setup the [MPI.jl]() package, | ||
such that `mpiexecjl` is created on the command line. | ||
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You can than run it with: | ||
mpiexecjl -n 4 --project=. julia Tutorial_Chmy_MPI.jl | ||
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The full file can be downloaded [here](../../../tutorials/Tutorial_Chmy_MPI.jl) | ||
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--- | ||
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*This page was generated using [Literate.jl](https://github.com/fredrikekre/Literate.jl).* | ||
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# # Create an initial model setup for Chmy and run it in parallel | ||
# | ||
# ## Aim | ||
# In this tutorial, your will learn how to use [Chmy](https://github.com/PTsolvers/Chmy.jl) to perform a 2D diffusion simulation | ||
# on one or multiple CPU's or GPU's. | ||
# `Chmy` is a package that allows you to specify grids and fields and create finite difference simulations | ||
# | ||
# ## 1. Load Chmy and required packages | ||
using Chmy, Chmy.Architectures, Chmy.Grids, Chmy.Fields, Chmy.BoundaryConditions, Chmy.GridOperators, Chmy.KernelLaunch | ||
using KernelAbstractions | ||
using Printf | ||
using CairoMakie | ||
using GeophysicalModelGenerator | ||
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||
# In case you want to use GPU's, you need to sort out whether you have AMD or NVIDIA GPU's | ||
# and load the package accordingly: | ||
#= | ||
using AMDGPU | ||
AMDGPU.allowscalar(false) | ||
using CUDA | ||
CUDA.allowscalar(false) | ||
=# | ||
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# To run this in parallel you need to load this: | ||
using Chmy.Distributed | ||
using MPI | ||
MPI.Init() | ||
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||
# ## 2. Define computational routines | ||
# You need to specify compute kernel for the gradients: | ||
@kernel inbounds = true function compute_q!(q, C, χ, g::StructuredGrid, O) | ||
I = @index(Global, NTuple) | ||
I = I + O | ||
q.x[I...] = -χ * ∂x(C, g, I...) | ||
q.y[I...] = -χ * ∂y(C, g, I...) | ||
end | ||
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||
# You need to specify compute kernel to update the concentration | ||
@kernel inbounds = true function update_C!(C, q, Δt, g::StructuredGrid, O) | ||
I = @index(Global, NTuple) | ||
I = I + O | ||
C[I...] -= Δt * divg(q, g, I...) | ||
end | ||
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||
# And a main function is required: | ||
@views function main(backend=CPU(); nxy_l=(126, 126)) | ||
arch = Arch(backend, MPI.COMM_WORLD, (0, 0)) | ||
topo = topology(arch) | ||
me = global_rank(topo) | ||
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## geometry | ||
dims_l = nxy_l | ||
dims_g = dims_l .* dims(topo) | ||
grid = UniformGrid(arch; origin=(-2, -2), extent=(4, 4), dims=dims_g) | ||
launch = Launcher(arch, grid, outer_width=(16, 8)) | ||
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##@info "mpi" me grid | ||
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nx, ny = dims_g | ||
## physics | ||
χ = 1.0 | ||
## numerics | ||
Δt = minimum(spacing(grid))^2 / χ / ndims(grid) / 2.1 | ||
## allocate fields | ||
C = Field(backend, grid, Center()) | ||
P = Field(backend, grid, Center(), Int32) # phases | ||
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q = VectorField(backend, grid) | ||
C_v = (me==0) ? KernelAbstractions.zeros(CPU(), Float64, size(interior(C)) .* dims(topo)) : nothing | ||
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## Use the `GeophysicalModelGenerator` to set the initial conditions. Note that | ||
## you have to call this for a `Phases` and a `Temp` grid, which we call `C` here. | ||
add_box!(P,C,grid, xlim=(-1.0,1.0), zlim=(-1.0,1.0), phase=ConstantPhase(4), T=ConstantTemp(400)) | ||
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## set BC's and updates the halo: | ||
bc!(arch, grid, C => Neumann(); exchange=C) | ||
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## visualisation | ||
fig = Figure(; size=(400, 320)) | ||
ax = Axis(fig[1, 1]; aspect=DataAspect(), xlabel="x", ylabel="y", title="it = 0") | ||
plt = heatmap!(ax, centers(grid)..., interior(C) |> Array; colormap=:turbo) | ||
Colorbar(fig[1, 2], plt) | ||
## action | ||
nt = 100 | ||
for it in 1:nt | ||
(me==0) && @printf("it = %d/%d \n", it, nt) | ||
launch(arch, grid, compute_q! => (q, C, χ, grid)) | ||
launch(arch, grid, update_C! => (C, q, Δt, grid); bc=batch(grid, C => Neumann(); exchange=C)) | ||
end | ||
KernelAbstractions.synchronize(backend) | ||
gather!(arch, C_v, C) | ||
if me == 0 | ||
fig = Figure(; size=(400, 320)) | ||
ax = Axis(fig[1, 1]; aspect=DataAspect(), xlabel="x", ylabel="y", title="it = 0") | ||
plt = heatmap!(ax, C_v; colormap=:turbo) # how to get the global grid for axes? | ||
Colorbar(fig[1, 2], plt) | ||
save("out_gather_$nx.png", fig) | ||
end | ||
return | ||
end | ||
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# In the code above, the part that calls `GMG` is: | ||
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# ```julia | ||
# add_box!(P,C,grid, xlim=(-1.0,1.0), zlim=(-1.0,1.0), phase=ConstantPhase(4), T=ConstantTemp(400)) | ||
# ``` | ||
# which works just like any of the other GMG function. | ||
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||
# ## 3. Run the simulation on one CPU machine or GPU card: | ||
|
||
# Running the code on the CPU is done with this: | ||
n = 128 | ||
main(; nxy_l=(n, n) .- 2) | ||
|
||
# If you instead want to run this on AMD or NVIDIA GPU's do this: | ||
## main(ROCBackend(); nxy_l=(n, n) .- 2) | ||
## main(CUDABackend(); nxy_l=(n, n) .- 2) | ||
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# And we need to finalize the simulation with | ||
MPI.Finalize() | ||
|
||
|
||
# ## 4. Run the simulation on an MPI-parallel machine | ||
# If you want to run this on multiple cores, you will need to setup the [MPI.jl]() package, | ||
# such that `mpiexecjl` is created on the command line. | ||
# | ||
# You can than run it with: | ||
# mpiexecjl -n 4 --project=. julia Tutorial_Chmy_MPI.jl | ||
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||
# The full file can be downloaded [here](../../../tutorials/Tutorial_Chmy_MPI.jl) | ||
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#src Note: The markdown page is generated using: | ||
#src Literate.markdown("tutorials/Tutorial_Chmy_MPI.jl","docs/src/man",keepcomments=true, execute=false, codefence = "```julia" => "```") |