 // Perform the MHA update on the n characteristics, done in parallel on the GPU.
 __global__
 void update_chi(double* chi, double* meas, double* meas_unc, int n, double* logdens, double* prop_cholfact,
-                curandState* state, int current_iter, double* p_mha_ratio)
+                curandState* state, int current_iter)
 {
 	int i = blockDim.x * blockIdx.x + threadIdx.x;
 	if (i < n)

            for (int k=0; k<(j+1); k++) {
                // transform the unit proposal to the centered proposal, drawn from a multivariate normal
                // or t-distribution.

                // DOUBLE CHECK THIS: DOES NOT LOOK RIGHT, WHY DOES K NOT APPEAR????
                scaled_proposal_j += cholfactor[cholfact_index] * snorm_deviate[j];
                cholfact_index++;
            }
            scaled_proposal_j = 0.0;

    int naccept_theta = 0;
    std::cout << "Running MCMC Sampler...." << std::endl;

    thrust::host_vector<double> h_logdens;

    for (int i=0; i<mcmc_iter; i++) {
