Additionally, to avoid gradients with infinite means even if DL is not contractive, we consider a spectral normalisation, so that instead of computing recursively η0 = ε and ηk = DLηk 1 for k {1,...,N},weset η0 =εand The motivation was to have a quadratic increase for the penalty term if the largest absolute eigenvalue approaches 1, and then smoothly switch to a linear function for values larger than δ2. The suggested approach can perform poorly for non-convex potentials or even convex potentials such as arsing in a logistic regression model for some data sets. The idea now is to run HMC with unit mass matrix for the transformed variables z = f 1(q) where q π. Hessian-vector products can similarly be computed using vector-Jacobian products: With g(z) = grad( U,z), we then compute 2 U(z)w = vjp(g,z,w)> for z = f 1(stop grad(f(zbL/2c)). We also stop all U gradients, i.e.

Hamiltonian Monte Carlo (HMC) is a popular Markov Chain Monte Carlo (MCMC) algorithm to sample from an unnormalized probability distribution.

Severe data imbalance naturally exists among web-scale vision-language datasets.

However, these works face some limitations and challenges.

For each convolutional layer, we would firstly apply a ReLU activation function right after the convolution,andthenapplyamaxpoolingwith kernel_size=2,stride=2toextractthefeature map.