diff --git a/GPy/inference/latent_function_inference/exact_gaussian_inference.py b/GPy/inference/latent_function_inference/exact_gaussian_inference.py
index 922b52f4..cf74aa17 100644
--- a/GPy/inference/latent_function_inference/exact_gaussian_inference.py
+++ b/GPy/inference/latent_function_inference/exact_gaussian_inference.py
@@ -46,7 +46,7 @@ class ExactGaussianInference(object):
         alpha, _ = dpotrs(LW, YYT_factor, lower=1)
 
         log_marginal =  0.5*(-Y.size * log_2_pi - Y.shape[1] * W_logdet - np.sum(alpha * YYT_factor))
-
+        
         dL_dK = 0.5 * (tdot(alpha) - Y.shape[1] * Wi)
 
         #TODO: does this really live here?
diff --git a/GPy/inference/latent_function_inference/var_dtc.py b/GPy/inference/latent_function_inference/var_dtc.py
index 1d998fcb..0be8f74c 100644
--- a/GPy/inference/latent_function_inference/var_dtc.py
+++ b/GPy/inference/latent_function_inference/var_dtc.py
@@ -77,7 +77,8 @@ class VarDTC(object):
         num_inducing = Z.shape[0]
         num_data = Y.shape[0]
         # kernel computations, using BGPLVM notation
-        Kmm = kern.K(Z)
+        
+        Kmm = kern.K(Z) +np.eye(Z.shape[0]) * self.const_jitter
 
         Lm = jitchol(Kmm)