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using StaticArrays | |
function gravitate!(x::AbstractArray{<:Real, 2}, a::AbstractArray{<:Real, 2}, | |
m::AbstractArray{<:Real, 1}) | |
@assert size(x) == size(a) | |
@assert size(m)[1] == size(x)[1] | |
@assert size(x)[2] == 3 | |
G = 6.6742367e-11 | |
fill!(a, 0) | |
for i in 1:length(m) | |
for j in 1:length(m) | |
if i == j | |
continue | |
end | |
@inbounds dx = x[i,1] - x[j,1] | |
@inbounds dy = x[i,2] - x[j,2] | |
@inbounds dz = x[i,3] - x[j,3] | |
r = hypot(dx, dy, dz) | |
@inbounds prefactor = -G/r^3 * m[j] | |
@inbounds a[i,1] = muladd(prefactor, dx, a[i,1]) | |
@inbounds a[i,2] = muladd(prefactor, dy, a[i,2]) | |
@inbounds a[i,3] = muladd(prefactor, dz, a[i,3]) | |
end | |
end | |
end | |
function simulate!(x::AbstractArray{<:Real, 2}, v::AbstractArray{<:Real, 2}, | |
a::AbstractArray{<:Real, 2}, m::AbstractArray{<:Real, 1} | |
; dt::Real=0.08, tmax::Real=3.6525e8) | |
@assert size(x) == size(a) | |
@assert size(x) == size(v) | |
@assert size(m)[1] == size(x)[1] | |
@assert size(x)[2] == 3 | |
hdt = dt / 2 | |
t = 0 | |
while t < tmax | |
@. x += hdt * v | |
gravitate!(x, a, m) | |
@. v += dt * a | |
@. x += hdt * v | |
t += dt | |
end | |
end | |
function main(;dt::Real=0.08, tmax::Real=3.6525e8) | |
# Arrays (initialized to zero by default) | |
x = zeros(2,3) | |
v = zeros(2,3) | |
a = zeros(2,3) | |
@inbounds x[2,1] = 0.0162 | |
@inbounds x[2,2] = 6.57192058353e-15 | |
@inbounds x[2,3] = 5.74968548652e-16 | |
@inbounds v[2,1] = -1.48427302304e-14 | |
@inbounds v[2,2] = 0.0399408809121 | |
@inbounds v[2,3] = 0.00349437429104 | |
m = [0.08, 3.0e-6] # M_Sun | |
simulate!(x, v, a, m, dt=dt, tmax=tmax) | |
println("Positions:", x) | |
end | |
function static_main(;dt::Real=0.08, tmax::Real=3.6525e8) | |
# Arrays (initialized to zero by default) | |
x = @MMatrix zeros(2,3) | |
v = @MMatrix zeros(2,3) | |
a = @MMatrix zeros(2,3) | |
@inbounds x[2,1] = 0.0162 | |
@inbounds x[2,2] = 6.57192058353e-15 | |
@inbounds x[2,3] = 5.74968548652e-16 | |
@inbounds v[2,1] = -1.48427302304e-14 | |
@inbounds v[2,2] = 0.0399408809121 | |
@inbounds v[2,3] = 0.00349437429104 | |
m = [0.08, 3.0e-6] # M_Sun | |
simulate!(x, v, a, m, dt=dt, tmax=tmax) | |
println("Positions:", x) | |
end |
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