to retrieve phase space distribution function

matlab/compute_fa.m

+function FF = compute_fa(Napj, spar, xperp)
+%% Compute the dispersion function from the moment hierarchi decomp.
+% Normalized Hermite
+Hp = @(p,s) polyval(HermitePoly(p),s)./sqrt(2.^p.*factorial(p));
+% Laguerre
+Lj = @(j,x) polyval(LaguerrePoly(j),x);
+% Maxwellian factor
+FaM = @(s,x) exp(-s.^2-x);
+
+[SS, XX] = meshgrid(spar, xperp); %meshgrid for efficient evaluation
+
+FF = 0 .* SS;
+
+[Pmax,Jmax] = size(Napj);
+
+FAM = FaM(SS,XX);
+for p_ = 0:Pmax-1
+    HH = Hp(p_,SS);
+    for j_ = 0:Jmax-1
+        LL = Lj(j_,XX);
+        FF = FF + Napj(p_+1,j_+1)*HH.*LL.*FAM;
+    end
+end
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