comments

Resample/Specular/ComputeFluxScalar.cpp

@@ -84,8 +84,7 @@ std::vector<Spinor> computeTR(const SliceStack& slices, const std::vector<comple
         return TR;
     }
 
-    // Calculate transmission/refraction coefficients t_r for each layer, from bottom to top.
-    // Starting from TR[X[N - 1]] = {1.0, 0.0} as set above.
+    // Parratt algorithm, step 1: compute r/t ratios from bottom to top.
     std::vector<complex_t> tfactor(N - 1);
     for (size_t i = N - 1; i > 0; i--) {
         const size_t jthis = X[i - 1];
@@ -101,8 +100,7 @@ std::vector<Spinor> computeTR(const SliceStack& slices, const std::vector<comple
         TR[jthis].v = delta * (slm + slp * TR[jlast].v) * f;
     }
 
-    // Now correct all amplitudes by dividing by the remaining tfactor in forward direction.
-    // At some point this divison underflows; from there on all further amplitudes are set to zero.
+    // Parrat algorithm, step 2: compute r and t from top to bottom.
     complex_t t = 1;
     for (size_t i = 1; i < N; ++i) {
         t = t * tfactor[i - 1];