latticegpu.jl/src/YM/YMflow.jl
2021-10-02 09:27:21 +02:00

115 lines
3.2 KiB
Julia

###
### "THE BEER-WARE LICENSE":
### Alberto Ramos wrote this file. As long as you retain this
### notice you can do whatever you want with this stuff. If we meet some
### day, and you think this stuff is worth it, you can buy me a beer in
### return. <alberto.ramos@cern.ch>
###
### file: YMflow.jl
### created: Sat Sep 25 08:37:14 2021
###
"""
function add_zth_term(ymws::YMworkspace, U, lp)
Assuming that the gauge improved (LW) force is in ymws.frc1, this routine
adds the "Zeuthen term" and returns the full zeuthen force in ymws.frc1
"""
function add_zth_term(ymws::YMworkspace, U, lp)
CUDA.@sync begin
CUDA.@cuda threads=lp.bsz blocks=lp.rsz krnl_add_zth!(ymws.frc1,ymws.frc2,U,lp)
end
ymws.frc1 .= ymws.frc2
return nothing
end
function krnl_add_zth!(frc, frc2::AbstractArray{TA}, U::AbstractArray{TG}, lp::SpaceParm{N,M,D}) where {TA,TG,N,M,D}
b, r = CUDA.threadIdx().x, CUDA.blockIdx().x
Ush = @cuStaticSharedMem(TG, D)
Fsh = @cuStaticSharedMem(TA, D)
@inbounds for id in 1:N
Ush[b] = U[b,id,r]
Fsh[b] = frc[b,id,r]
sync_threads()
bu, ru = up((b,r), id, lp)
bd, rd = dw((b,r), id, lp)
if ru == r
X = Fsh[bu]
else
X = frc[bu,id,ru]
end
if rd == r
Y = Fsh[bd]
Ud = Ush[bd]
else
Y = frc[bd,id,rd]
Ud = U[bd,id,rd]
end
frc2[b,id,r] = (5/6)*Fsh[b] + (1/6)*(projalg(Ud\Y*Ud) +
projalg(Ush[b]*X/Ush[b]))
end
return nothing
end
function flw_euler(U, ns, eps, c0, lp::SpaceParm, ymws::YMworkspace; add_zth=false)
for i in 1:ns
force_gauge(ymws, U, c0, lp)
if add_zth
add_zth_term(ymws::YMworkspace, U, lp)
end
U .= expm.(U, ymws.frc1, 2*eps)
end
return nothing
end
function flw_rk3(U, ns, eps, c0, lp::SpaceParm, ymws::YMworkspace; add_zth=false)
for i in 1:ns
e0 = eps/2
force_gauge(ymws, U, c0, lp)
if add_zth
add_zth_term(ymws::YMworkspace, U, lp)
end
ymws.mom .= ymws.frc1
U .= expm.(U, ymws.mom, e0)
e0 = -34*eps/36
e1 = 16*eps/9
force_gauge(ymws, U, c0, lp)
if add_zth
add_zth_term(ymws::YMworkspace, U, lp)
end
ymws.mom .= e0.*ymws.mom .+ e1.*ymws.frc1
U .= expm.(U, ymws.mom)
e1 = 6*eps/4
force_gauge(ymws, U, c0, lp)
if add_zth
add_zth_term(ymws::YMworkspace, U, lp)
end
ymws.mom .= e1.*ymws.frc1 .- ymws.mom
U .= expm.(U, ymws.mom)
end
return nothing
end
wfl_euler(U, ns, eps, lp::SpaceParm, ymws::YMworkspace) = flw_euler(U, ns, eps, 1, lp, ymws)
zfl_euler(U, ns, eps, lp::SpaceParm, ymws::YMworkspace) = flw_euler(U, ns, eps, 5.0/3.0, lp, ymws, add_zth=true)
wfl_rk3(U, ns, eps, lp::SpaceParm, ymws::YMworkspace) = flw_rk3(U, ns, eps, 1, lp, ymws)
zfl_rk3(U, ns, eps, lp::SpaceParm, ymws::YMworkspace) = flw_rk3(U, ns, eps, 5.0/3.0, lp, ymws, add_zth=true)