fix bug

Author: EigenSolver

src/analytics.jl

@@ -53,10 +53,11 @@ function analyticalrabi(t::AbstractVector{Float64}, ensemble::SpinEnsemble, h::R
     end
 end
 
-function analyticalfid(t::AbstractVector{Float64}, ensemble::SpinEnsemble)
+function analyticalfid(t::AbstractVector{Float64}, ensemble::SpinEnsemble;
+     spin=1/2::Real)
     @assert isdilute(ensemble)
 
     dim=ensemble.dim
     T2=coherencetime(ensemble)
-    return exp.(-(abs.(t/T2).^(1/dim)))
+    return spin*exp.(-(abs.(t/T2).^(dim/3)))
 end

test/test_dynamics.jl

@@ -12,16 +12,39 @@ import Statistics: mean, std
     the_curve=analyticalrabi(t,ensemble,h)
     mc_curve=rabi(t, ensemble, h; M=400, N=500)
 
-    rabi_error=abs.(mc_curve-the_curve)
-    avg_err=mean(rabi_error); std_err=std(rabi_error);
+    error=abs.(mc_curve-the_curve)
+    avg_err=mean(error); std_err=std(error);
 
-    scatter(t,mc_curve,labels="Numerical", fmt = :png)
+    scatter(t,mc_curve,labels="Numerical", 
+    fmt = :png, title="Rabi Oscillation", 
+    xlabel="t",
+    ylabel="f(t)")
     plot!(t, the_curve,labels="Analytical",linestyle=:dash)
     savefig("./.figs/rabi_test.png")
 
     println("mean error: ", avg_err)
     println("std error: ", std_err)
     @test avg_err<0.01
-    @test std_err<0.1
-    # fid(ensemble)
+    @test std_err<0.01
+
+    dt=T2/200; 
+    t=0:dt:T2
+    println("generating free induction decay curve...")
+    the_curve=analyticalfid(t,ensemble)
+    mc_curve=fid(t, ensemble; M=400, N=500)
+
+    error=abs.(mc_curve-the_curve)
+    avg_err=mean(error); std_err=std(error);
+    
+    scatter(t,mc_curve,labels="Numerical", 
+    fmt = :png, title="Free Induction Decay", 
+    xlabel="t",
+    ylabel="f(t)")
+    plot!(t, the_curve,labels="Analytical",linestyle=:dash)
+    savefig("./.figs/fid_test.png")
+
+    println("mean error: ", avg_err)
+    println("std error: ", std_err)
+    @test avg_err<0.01
+    @test std_err<0.01    
 end