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Fix the rotary embeddings for the new phi implementation. (#1582)

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* Fix the rotary embeddings for the new phi implementation.

* Match the activation.

* KV cache fix.

* Use the config activation function.
This commit is contained in:
Laurent Mazare
2024-01-13 19:44:41 +01:00
committed by GitHub
parent 539ead927a
commit 88618255cb
1 changed files with 16 additions and 18 deletions
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34
candle-transformers/src/models/phi.rs
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@ -38,6 +38,7 @@ impl Config {
#[derive(Debug, Clone)]
struct RotaryEmbedding {
dim: usize,
sin: Tensor,
cos: Tensor,
}
@ -55,29 +56,24 @@ impl RotaryEmbedding {
.to_dtype(DType::F32)?
.reshape((cfg.max_position_embeddings, 1))?;
let freqs = t.matmul(&inv_freq)?;
let emb = Tensor::cat(&[&freqs, &freqs], D::Minus1)?;
Ok(Self {
sin: freqs.sin()?,
cos: freqs.cos()?,
dim,
sin: emb.sin()?,
cos: emb.cos()?,
})
}
fn apply_rotary_emb(&self, xs: &Tensor, seqlen_offset: usize) -> Result<Tensor> {
let (_b_size, seqlen, _, _headdim) = xs.dims4()?;
let (_rotary_seqlen, rotary_dim) = self.cos.dims2()?;
let rotary_dim = rotary_dim * 2;
let xs_rot = xs.i((.., .., .., ..rotary_dim))?;
let xs_pass = xs.i((.., .., .., rotary_dim..))?;
let (_b_size, _num_heads, seq_len, _headdim) = xs.dims4()?;
let xs_rot = xs.i((.., .., .., ..self.dim))?;
let xs_pass = xs.i((.., .., .., self.dim..))?;
let xs12 = xs_rot.chunk(2, D::Minus1)?;
let (xs1, xs2) = (&xs12[0], &xs12[1]);
let c = self.cos.narrow(0, seqlen_offset, seqlen)?.unsqueeze(1)?;
let s = self.sin.narrow(0, seqlen_offset, seqlen)?.unsqueeze(1)?;
let xs_rot = Tensor::cat(
&[
(xs1.broadcast_mul(&c)? - xs2.broadcast_mul(&s)?)?,
(xs1.broadcast_mul(&s)? + xs2.broadcast_mul(&c)?)?,
],
D::Minus1,
)?;
let c = self.cos.narrow(0, seqlen_offset, seq_len)?;
let s = self.sin.narrow(0, seqlen_offset, seq_len)?;
let rotate_half = Tensor::cat(&[&xs2.neg()?, &xs1], D::Minus1)?;
let xs_rot = (xs_rot.broadcast_mul(&c)? + rotate_half.broadcast_mul(&s)?)?;
Tensor::cat(&[&xs_rot, &xs_pass], D::Minus1)
}
}
@ -97,6 +93,8 @@ impl MLP {
Ok(Self {
fc1,
fc2,
// This does not match the mixformers implementation where Gelu is used rather than
// GeluNew.
act: cfg.hidden_act,
})
}
@ -216,7 +214,7 @@ impl Attention {
// Rotary embeddings.
let seqlen_offset = match &self.kv_cache {
None => 0,
Some((prev_k, _)) => prev_k.dim(1)?,
Some((prev_k, _)) => prev_k.dim(2)?,
};
let query_states = self
.rotary_emb
@ -351,7 +349,7 @@ impl Model {
Some(get_mask(seq_len, xs.device())?)
};
for layer in self.layers.iter_mut() {
xs = layer.forward(&xs, mask.as_ref())?
xs = layer.forward(&xs, mask.as_ref())?;
}
xs.apply(&self.final_layernorm)?
.narrow(1, seq_len - 1, 1)?