[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify code snippets into one of the following categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']."}, {'role': 'user', 'content': 'Identify the single most appropriate category to which the provided code belongs. Provide your response as a single category label without any additional information, commentary, or personal opinions.\\nPython Code:%%time\nsamples = []\nXdim = XX.shape[0]\nbb = np.ones(4) * 0\nfor i in range(nsample):\nidx = np.random.choice(Xdim, round(Xdim*size), replace = False)\nXb = XX[idx,:]\nyb = y[idx]\nbb = sghmc_vectorNew(sg_gradU, etaSGHMC, L, alpha, bb, V, Xb, yb, Sigma_beta, s)\nsamples.append(bb.copy())'}, {'role': 'assistant', 'content': 'modelling'}]