    def forward(self, x, latents):
        """
        Args:
            x (torch.Tensor): image features
                shape (b, T, n1, D)
            latent (torch.Tensor): latent features
                shape (b, T, n2, D)
        """
        x = self.norm_media(x)
        latents = self.norm_latents(latents)

        h = self.heads

        q = self.to_q(latents)
        kv_input = torch.cat((x, latents), dim=-2)
        k, v = self.to_kv(kv_input).chunk(2, dim=-1)
        q, k, v = rearrange_many((q, k, v), "b t n (h d) -> b h t n d", h=h)
        q = q * self.scale

        # attention
        sim = einsum("... i d, ... j d  -> ... i j", q, k)
        sim = sim - sim.amax(dim=-1, keepdim=True).detach()
        attn = sim.softmax(dim=-1)

        out = einsum("... i j, ... j d -> ... i d", attn, v)
        out = rearrange(out, "b h t n d -> b t n (h d)", h=h)
        return self.to_out(out)
Args:
x (torch.Tensor): image features
shape (b, T, n1, D)
latent (torch.Tensor): latent features
shape (b, T, n2, D)
open_flamingo/src/helpers.py