generate random ICD-9 codes
generate_random_short_icd9(n = 50000)generate_random_decimal_icd9(n = 50000)
generate_random_pts(...)
generate_random_ordered_pts(...)
generate_random_unordered_pts(num_patients = 50000, dz_per_patient = 20,
n = num_patients, np = dz_per_patient, fun = generate_random_short_icd9)
generate_random_short_ahrq_icd9(n = 50000)