Revert "Lagrange interpolation"

This reverts commit 4e595cb.

Author: ianalexis

src/libslic3r/GCode.cpp

@@ -149,22 +149,7 @@ static double calculate_pressure_advance_for_nozzle(const std::string& pa_string
         if (i < pa_values.size() - 1 && nozzle_diameter > nozzle) {
             auto& [next_nozzle, next_pa] = pa_values[i + 1];
             if (nozzle_diameter <= next_nozzle) {
-                if (pa_values.size() >= 3) {
-                    // Lagrange interpolation
-                    double result = 0.0;
-                    for (size_t k = 0; k < pa_values.size(); ++k) {
-                        double term = pa_values[k].second;
-                        for (size_t m = 0; m < pa_values.size(); ++m) {
-                            if (k != m) {
-                                term *= (nozzle_diameter - pa_values[m].first) / (pa_values[k].first - pa_values[m].first);
-                            }
-                        }
-                        result += term;
-                    }
-                    return result;
-                } else {
-                    return pa + (next_pa - pa) * (nozzle_diameter - nozzle) / (next_nozzle - nozzle);
-                }
+                return pa + (next_pa - pa) * (nozzle_diameter - nozzle) / (next_nozzle - nozzle);
             }
         }
     }