I am new to MCMC and theano, and now I have three equations similar to the following equations：

r1 = ……

r2 = ……

r3 = ……

R_a = r1 + r2

R_b = r1 - r3

R_c = - r2 - r3;

Due to the fact that experimental data of R_a, R_b and R_c is available, so I want to use Likehood of R_a, R_b and R_c to do sampling as follow:

R_a_likehood = pm.Normal(‘R_a_likehood’,mu = R_a_obs, sd = sigma, observed = R_a_data)

R_b_likehood = pm.Normal(‘R_b_likehood’,mu = R_b_obs, sd = sigma, observed = R_b_data)

R_c_likehood = pm.Normal(‘R_c_likehood’,mu = R_c_obs, sd = sigma, observed = R_c_data)

But it seems that only one likehood can be used.

I tried to use np.vstack to combine the array, but I encountered the problem of “ValueError: setting an array element with a sequence.”

So how can I do MCMC sampling with Multiple likelihood functions？