fastslow

gistfile1.txt

K = 5
N = 3
z = [rand(20000, K) for i =1:N]
P = [rand(20000) for i = 1:N]
Pm = rand(20000, N)
Pv = [@view Pm[:, j] for j = 1:N]
cache = zeros(20000, K)

function test1(P, z)
    for i in eachindex(P)
        cache .= P[i].*z[i]
    end
end

function test2(P, z)
    for i = 1:size(P, 2)
        cache .= P[:, i].*z[i]
    end
end

function test3(P, z)
J, I, K = length(P), size(z[1])...
    for j = 1:J
        for k = 1:K
            for i = 1:I
                cache[i, k] = P[j][i]*z[j][i,k]
            end
        end
    end
end

function test4(P, z)
J, I, K = length(P), size(z[1])...
    for j = 1:J
        _P = P[j]
        _z = z[j]
        for k = 1:K
            for i = 1:I
                cache[i, k] = _P[i]*_z[i,k]
            end
        end
    end
end

@benchmark test1(P, z)
@benchmark test1(Pv, z)
@benchmark test2(Pm, z)
@benchmark test3(P, z)
@benchmark test4(P, z)