CVAE Problem Setup

Back to CVAE methodology

This note isolates the basic factorization target and the role of each model component.

Problem Setup

We assume an input-conditioned generation task with:

  • input xx,
  • latent strategy zz,
  • output sequence y=(y1,…,yT)y = (y_1, \dots, y_T).

The frozen entangled base model is:

pθ(y∣x).p_\theta(y \mid x).

The target factorization is:

  • discrete zz:
p(y∣x)=∑z=1Kpψ(y∣x,z) pϕ(z∣x),p(y \mid x) = \sum_{z=1}^{K} p_\psi(y \mid x, z)\, p_\phi(z \mid x),
  • continuous zz:
p(y∣x)=∫pψ(y∣x,z) pϕ(z∣x) dz.p(y \mid x) = \int p_\psi(y \mid x, z)\, p_\phi(z \mid x)\, dz.

Interpretation:

  • pϕ(z∣x)p_\phi(z \mid x) is a strategy router,
  • pψ(y∣x,z)p_\psi(y \mid x, z) is a strategy-conditioned decoder,
  • qξ(z∣x,y)q_\xi(z \mid x, y) is a variational inference model used during training.

Training data for post-training is drawn from the frozen base distribution:

(x,y)∼D,D(x,y)=Dx(x) pθ(y∣x).(x, y) \sim \mathcal{D}, \qquad \mathcal{D}(x, y) = \mathcal{D}_x(x)\, p_\theta(y \mid x).
Why this setup matters

The methodology is not about learning p(y∣x)p(y \mid x) from scratch. It is about refactoring an already strong entangled model so that the latent variable can act as a reusable high-level strategy handle.

Next

Next: CVAE model components

Built with LogoFlowershow