def calc_R_matrix(beta, gamma, alpha):
    # calculate R matrix from beta value

    # calc contact matrix C
    C = func.calc_contact_matrix(alpha)

    # assign components of C matrix
    C_cc = C.item((0, 0))
    C_ca = C.item((0, 1))
    C_ac = C.item((1, 0))
    C_aa = C.item((1, 1))

    # multiply components of matrix C by alpha or (1-alpha)
    mx_11 = C_cc * alpha
    mx_12 = C_ca * alpha
    mx_21 = C_ac * (1 - alpha)
    mx_22 = C_aa * (1 - alpha)

    # calc R matrix
    # SB needs to check - might be (beta / (beta + gamma))
    R = (beta / gamma) * (np.matrix([[mx_11, mx_12], [mx_21, mx_22]]))

    return R
avg_q_ad = func.weighted_avg_q(adult, d_mean_contacts, d_num_part)

n = func.calc_eta(avg_q_ch, avg_q_ad) # ratio of avg # contacts (adult / child)
#print n # n = 0.752

#Ec, Ea = func.calc_epsilon(avg_q_ch, avg_q_ad, C_ca, a, n)
#print Ec
#print Ea

####################################
#calc epsiolon for Germany (closest E to Europe average in Apollini)
#ad_contacts_w_5_9 = [0.03, 0.17, 0.26, 0.49, 0.23, 0.09, 0.20, 0.11, 0.14, 0.11]
#ad_contacts_w_10_14 = [0.12, 0.16, 0.14, 0.62, 0.67, 0.35, 0.16, 0.07, 0.07, 0.18]
#ad_contacts_w_15_19 = [0.90, 0.28, 0.19, 0.46, 1.11, 1.21, 0.27, 0.26, 0.11, 0.15]

C = func.calc_contact_matrix(a, n, E, avg_q_ch)

############################

## DISEASE ##

## Infc_list = [patient_Zero]
## Susc_list = [everyone_else]
## for t (time steps) in (1, 100):
    ## S --> I ?
    ## for s in susc:
        ## infect nodes with prob (1-e^-B(# of infec contacts)) # infected degree = #infected contacts
    
    ## I --> R ?
    ## for i in infc:
        ## recover with prob u
    us_popdata = csv.reader(open("Dropbox/Anne_Bansal_lab/SDI_Data/totalpop_age.csv", "r"), delimiter=",")
    dict_popdata, ages, years = pop_func.import_popdata(us_popdata, 0, 1, 2)
    dict_childpop, dict_adultpop = pop_func.pop_child_adult(dict_popdata, years)
    # READ Germany contact data
    filename_germ_contact_data = "Dropbox/Anne_Bansal_lab/Contact_Data/polymod_germany_contact_matrix_Mossong_2008.csv"
    filename_germ_pop_data = "Dropbox/Anne_Bansal_lab/UNdata_Export_2008_Germany_Population.csv"

    # DEFINE POPULATION PARAMETERS
    year = 2010
    alpha = pop_func.calc_alpha(year, dict_childpop, dict_adultpop)
    d_metro_age_pop = pop_func.calc_metro_age_pop(filename_metropop, alpha)
    ch_travelers_r = 0.0  # fraction of children who travel
    ad_travelers_s = 1

    # CONTACT MATRIX
    C = pop_func.calc_contact_matrix(filename_germ_contact_data, filename_germ_pop_data, alpha)
    # print C

    # DEFINE DISEASE PARAMETERS
    R0 = 1.2
    gamma = 0.5  # recovery rate based on (1/gamma) day infectious period
    # beta = calculate_beta(R0, gamma, air_network)
    # beta = 0
    # beta = 0.037 #gamma 0.5
    # jbeta = 0.005
    num_metro_zeros = 1  # set how many metros to select patients from to start with
    num_child_zeros = 1
    num_adult_zeros = 0
    time_end = 150

    # DEFINE TRAVEL PARAMETERS