docs: private INDArray phi(INDArray diffSquared, INDArray sigma) {
          // 1/sqrt(2PIs^2) * e^((in-u)^2/2*s^2)
          INDArray minustwovariance = sigma.mul(sigma).muli(2).negi();
  
          // This is phi_i(x,mu,sigma)
          INDArray likelihoods = Transforms.exp(diffSquared.divi(minustwovariance))
                          .divi(Transforms.pow(sigma.mul(SQRT_TWO_PI), (double) mLabelWidth));
  
          return likelihoods;
      }