diff --git a/Utils.jl b/Utils.jl
index 80748f1..2756c42 100644
--- a/Utils.jl
+++ b/Utils.jl
@@ -77,6 +77,10 @@ function lowpass_filter(i; σ=1)
   return r
 end
 
+function residuals(I_data, I_model, err)
+  return (I_data .- I_model ./ err) .^ 2
+end
+
 function chi2(I_data, I_model, err)
   return sum((I_data .- I_model ./ err) .^ 2)
 end
diff --git a/test.jl b/test.jl
index 2f602fb..b3e4885 100644
--- a/test.jl
+++ b/test.jl
@@ -68,14 +68,21 @@ padding_factor[18] = 10.0
 
 bounds = MH.boxconstraints(lb=lb_reduced, ub=ub_reduced)
 
-function obj(P)
+function obj_χ2(P)
   I_model, neg_H20 = intensity_reduced(P)
   χ2 = Utils.chi2(I_data, I_model, err)
   factor = (neg_H20 == 0 ? 1.0 : 5.0 * (neg_H20 + 1))
   return factor * χ2
 end
 
-barriered_obj = Utils.add_log_barriers(obj, simple_bounds; padding_factor=padding_factor)
+function obj_residuals(P)
+  I_model, neg_H20 = intensity_reduced(P)
+  residuals = Utils.residuals(I_data, I_model, err)
+  factor = (neg_H20 == 0 ? 1.0 : 5.0 * (neg_H20 + 1))
+  return factor * residuals
+end
+
+barriered_obj = Utils.add_log_barriers(obj_residuals, simple_bounds; padding_factor=padding_factor)
 
 information = MH.Information(f_optimum=0.0)
 information = MH.Information()