using LatticeGPU, CUDA

#Test for the relation Dw(n|m)^{-1} e^(ipm) = D(p)^{-1} e^{ipn} with a given momenta (if p=0 its randomized), spin and color

function Dwpw_test(;p=0,s=1,c=1)
lp = SpaceParm{4}((16,16,16,16), (4,4,4,4), 0, (0,0,0,0,0,0))
gp = GaugeParm{Float64}(SU3{Float64}, 6.0, 1.0)
ymws = YMworkspace(SU3, Float64, lp)
dpar = DiracParam{Float64}(SU3fund,1.3,1.0,(1.0,1.0,1.0,1.0),0.0)
dws = DiracWorkspace(SU3fund{Float64},Float64,lp);

p==0 ? p = Int.(round.(lp.iL.*rand(4),RoundUp)) : nothing
U = fill!(vector_field(SU3{Float64},lp),one(SU3{Float64}))

rm = 2* pi* p./(lp.iL)
rmom=(rm[1],rm[2],rm[3],rm[4])

pwave = fill!(scalar_field(Spinor{4,SU3fund{Float64}},lp),zero(eltype(scalar_field(Spinor{4,SU3fund{Float64}},lp))))
prop = scalar_field(Spinor{4,SU3fund{Float64}},lp)
prop_th = fill!(scalar_field(Spinor{4,SU3fund{Float64}},lp),zero(eltype(scalar_field(Spinor{4,SU3fund{Float64}},lp))))

#Generate plane wave

for x in 1:lp.iL[1] for y in 1:lp.iL[2] for z in 1:lp.iL[3] for t in 1:lp.iL[4]
CUDA.@allowscalar pwave[point_index(CartesianIndex{lp.ndim}((x,y,z,t)),lp)...] = exp(im * (x*rmom[1] + y*rmom[2] + z*rmom[3] + t*rmom[4]))*Spinor{4,SU3fund{Float64}}(ntuple(i -> (i==s)*SU3fund{Float64}(ntuple(j -> (j==c)*1.0,3)...),4))
end end end end

#Th solution

if s == 1
    vals = (dpar.m0 + 4.0 - sum(cos.(rmom)),0.0,im*sin(rmom[4])+sin(rmom[3]),im*sin(rmom[2])+sin(rmom[1]))
    for x in 1:lp.iL[1] for y in 1:lp.iL[2] for z in 1:lp.iL[3] for t in 1:lp.iL[4]
    CUDA.@allowscalar prop_th[point_index(CartesianIndex{lp.ndim}((x,y,z,t)),lp)...] = exp(im * (x*rmom[1] + y*rmom[2] + z*rmom[3] + t*rmom[4]))*
    ( Spinor{4,SU3fund{Float64}}(ntuple(i -> SU3fund{Float64}(ntuple(j -> (j==c)*vals[i],3)...),4)) )/(sum((sin.(rmom)) .^2) + (dpar.m0+ 4.0 - sum(cos.(rmom)))^2)
    end end end end
elseif s == 2
    vals = (0.0,dpar.m0 + 4.0 - sum(cos.(rmom)),sin(rmom[1]) - im *sin(rmom[2]),-sin(rmom[3])+im*sin(rmom[4]))
    for x in 1:lp.iL[1] for y in 1:lp.iL[2] for z in 1:lp.iL[3] for t in 1:lp.iL[4]
    CUDA.@allowscalar prop_th[point_index(CartesianIndex{lp.ndim}((x,y,z,t)),lp)...] = exp(im * (x*rmom[1] + y*rmom[2] + z*rmom[3] + t*rmom[4]))*
    ( Spinor{4,SU3fund{Float64}}(ntuple(i -> SU3fund{Float64}(ntuple(j -> (j==c)*vals[i],3)...),4)) )/(sum((sin.(rmom)) .^2) + (dpar.m0+ 4.0 - sum(cos.(rmom)))^2)
    end end end end
elseif s == 3
    vals = (-sin(rmom[3])+im*sin(rmom[4]),-sin(rmom[1])-im*sin(rmom[2]),dpar.m0 + 4.0 - sum(cos.(rmom)),0.0)
    for x in 1:lp.iL[1] for y in 1:lp.iL[2] for z in 1:lp.iL[3] for t in 1:lp.iL[4]
    CUDA.@allowscalar prop_th[point_index(CartesianIndex{lp.ndim}((x,y,z,t)),lp)...] = exp(im * (x*rmom[1] + y*rmom[2] + z*rmom[3] + t*rmom[4]))*
    ( Spinor{4,SU3fund{Float64}}(ntuple(i -> SU3fund{Float64}(ntuple(j -> (j==c)*vals[i],3)...),4)) )/(sum((sin.(rmom)) .^2) + (dpar.m0+ 4.0 - sum(cos.(rmom)))^2)
    end end end end
else 
    vals = (-sin(rmom[1])+im*sin(rmom[2]),sin(rmom[3])+im*sin(rmom[4]),0.0,dpar.m0 + 4.0 - sum(cos.(rmom)))
    for x in 1:lp.iL[1] for y in 1:lp.iL[2] for z in 1:lp.iL[3] for t in 1:lp.iL[4]
    CUDA.@allowscalar prop_th[point_index(CartesianIndex{lp.ndim}((x,y,z,t)),lp)...] = exp(im * (x*rmom[1] + y*rmom[2] + z*rmom[3] + t*rmom[4]))*
    ( Spinor{4,SU3fund{Float64}}(ntuple(i -> SU3fund{Float64}(ntuple(j -> (j==c)*vals[i],3)...),4)) )/(sum((sin.(rmom)) .^2) + (dpar.m0+ 4.0 - sum(cos.(rmom)))^2)
    end end end end
end

#compute Sum{x} D^-1(x|y)P(y)

function krnlg5!(src)
    b=Int64(CUDA.threadIdx().x)
    r=Int64(CUDA.blockIdx().x)
    src[b,r] = dmul(Gamma{5},src[b,r])
    return nothing
end

CUDA.@sync begin
        CUDA.@cuda threads=lp.bsz blocks=lp.rsz krnlg5!(pwave)
end
g5Dw!(prop,U,pwave,dpar,lp)
CG!(prop,U,DwdagDw!,dpar,lp,dws,10000,1.0e-14)


dif = sum(norm2.(prop - prop_th))

if dif > 1.0e-15
        error("Dwpl test for s=",s,", c=",c," failed with difference: ",dif,"\n")
end

return dif
end

let
dif = 0.0
for i in 1:3 for j in 1:4
    dif += Dwpw_test(c=i,s=j)
end end

print("Dwpl test passed with average error ", dif/12,"\n")
end