Aufgabe 1

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using PyPlot


    

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function int2spin(integer,N)
    vec = split(string(bin(integer,N)),"")
    vec = map(x->parse(Int,x), vec)
    return vec-.5
end
function H(spins, J, h)
    N = length(spins)
    sum1 = 0
    for i in 1:N-1
        sum1 += spins[i]*spins[i+1]
    end
    return -J*sum1-h*sum(spins)
end
function boltz(spins, T, J, h)
    k_B = 1
    return exp(-H(spins, J, h)/(k_B*T))
end
function M(T, N, J, h)
    
    Z = 0
    for i in 0:2^N-1
        Z += boltz(int2spin(i,N), T, J, h)
    end
    
    sum1 = 0
    for i in 0:2^N-1
        spins = int2spin(i,N)
        sum1 += boltz(spins, T, J, h)*sum(spins)/Z
    end
    return sum1
end;


    

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J = 1; N = 14; h_list = [.1 .2 .3 1.]; steps = 101
T_list = linspace(.1,5,steps)
figure(1)
for h in h_list
    M_list = Array{Float64}(steps)
    for i in 1:steps
        M_list[i] = M(T_list[i], N, J, h)
    end
    plot(T_list, M_list, label="h=$h")
end
legend()
xlabel("Temperatur")
ylabel("Magnetisierung")
show()


    

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