ollama/model/models/gemma2/model.go
2025-04-03 13:12:24 -07:00

214 lines
6.7 KiB
Go

package gemma2
import (
"math"
"github.com/ollama/ollama/fs"
"github.com/ollama/ollama/kvcache"
"github.com/ollama/ollama/ml"
"github.com/ollama/ollama/ml/nn"
"github.com/ollama/ollama/model"
"github.com/ollama/ollama/model/input"
)
type Options struct {
hiddenSize, numHeads, numKVHeads int
attnKeyLen, attnValLen int
eps, ropeBase, ropeScale float32
attnLogitSoftcap float32
finalLogitSoftcap float32
largeModelScaling bool
}
type Model struct {
model.Base
model.SentencePieceModel
TokenEmbedding *nn.Embedding `gguf:"token_embd"`
Layers []Layer `gguf:"blk"`
OutputNorm *nn.RMSNorm `gguf:"output_norm"`
Output *nn.Linear `gguf:"output,alt:token_embd"` // just set to token_embd?
*Options
}
const (
gemma27BLayerCount = 46
)
func New(c fs.Config) (model.Model, error) {
m := Model{
SentencePieceModel: model.NewSentencePieceModel(
&model.Vocabulary{
Values: c.Strings("tokenizer.ggml.tokens"),
Scores: c.Floats("tokenizer.ggml.scores"),
Types: c.Uints("tokenizer.ggml.token_type"),
BOS: int32(c.Uint("tokenizer.ggml.bos_token_id")),
EOS: int32(c.Uint("tokenizer.ggml.eos_token_id")),
},
),
Layers: make([]Layer, c.Uint("block_count")),
Options: &Options{
hiddenSize: int(c.Uint("embedding_length")),
numHeads: int(c.Uint("attention.head_count")),
numKVHeads: int(c.Uint("attention.head_count_kv")),
attnKeyLen: int(c.Uint("attention.key_length")),
attnValLen: int(c.Uint("attention.value_length")),
eps: c.Float("attention.layer_norm_rms_epsilon"),
ropeBase: c.Float("rope.freq_base", 10000.0),
ropeScale: c.Float("rope.freq_scale", 1.0),
attnLogitSoftcap: c.Float("attn_logit_softcapping"),
finalLogitSoftcap: c.Float("final_logit_softcapping"),
},
}
slidingWindowLen := int32(c.Uint("attention.sliding_window"))
m.Cache = kvcache.NewWrapperCache(kvcache.NewSWACache(slidingWindowLen, m.Shift), kvcache.NewCausalCache(m.Shift))
m.Cache.SetConfig(ml.CacheConfig{})
return &m, nil
}
type SelfAttention struct {
Query *nn.Linear `gguf:"attn_q"`
Key *nn.Linear `gguf:"attn_k"`
Value *nn.Linear `gguf:"attn_v"`
Output *nn.Linear `gguf:"attn_output"`
}
func (sa *SelfAttention) Forward(ctx ml.Context, hiddenState, positionIDs ml.Tensor, cache kvcache.Cache, opts *Options) ml.Tensor {
batchSize := hiddenState.Dim(1)
ropeType := uint32(2)
q := sa.Query.Forward(ctx, hiddenState)
q = q.Reshape(ctx, opts.attnKeyLen, opts.numHeads, batchSize)
q = q.RoPE(ctx, positionIDs, nil, uint32(opts.attnKeyLen), ropeType, opts.ropeBase, opts.ropeScale)
if opts.largeModelScaling {
q = q.Scale(ctx, 1.0/math.Sqrt(float64(opts.hiddenSize/opts.numHeads)))
} else {
q = q.Scale(ctx, 1.0/math.Sqrt(float64(opts.attnKeyLen)))
}
k := sa.Key.Forward(ctx, hiddenState)
k = k.Reshape(ctx, opts.attnKeyLen, opts.numKVHeads, batchSize)
k = k.RoPE(ctx, positionIDs, nil, uint32(opts.attnKeyLen), ropeType, opts.ropeBase, opts.ropeScale)
v := sa.Value.Forward(ctx, hiddenState)
v = v.Reshape(ctx, opts.attnValLen, opts.numKVHeads, batchSize)
cache.Put(ctx, k, v)
k, v, mask := cache.Get(ctx)
q = q.Permute(ctx, 0, 2, 1, 3)
k = k.Permute(ctx, 0, 2, 1, 3)
v = v.Permute(ctx, 1, 2, 0, 3).Contiguous(ctx)
kq := k.Mulmat(ctx, q)
// logit softcap
kq = kq.Scale(ctx, 1.0/float64(opts.attnLogitSoftcap))
kq = kq.Tanh(ctx)
kq = kq.Scale(ctx, float64(opts.attnLogitSoftcap))
kq = kq.Add(ctx, mask)
kq = kq.Softmax(ctx)
kqv := v.Mulmat(ctx, kq)
kqv = kqv.Permute(ctx, 0, 2, 1, 3).Contiguous(ctx)
kqv = kqv.Reshape(ctx, opts.attnValLen*opts.numHeads, batchSize)
return sa.Output.Forward(ctx, kqv)
}
func (m *Model) Shift(ctx ml.Context, layer int, key, shift ml.Tensor) (ml.Tensor, error) {
return key.RoPE(ctx, shift, nil, uint32(m.Options.attnKeyLen), uint32(2), m.Options.ropeBase, m.Options.ropeScale), nil
}
type MLP struct {
Up *nn.Linear `gguf:"ffn_up"`
Down *nn.Linear `gguf:"ffn_down"`
Gate *nn.Linear `gguf:"ffn_gate"`
}
func (mlp *MLP) Forward(ctx ml.Context, hiddenState ml.Tensor, opts *Options) ml.Tensor {
hiddenState = mlp.Gate.Forward(ctx, hiddenState).GELU(ctx).Mul(ctx, mlp.Up.Forward(ctx, hiddenState))
return mlp.Down.Forward(ctx, hiddenState)
}
type Layer struct {
AttentionNorm *nn.RMSNorm `gguf:"attn_norm"`
SelfAttention *SelfAttention
PostAttentionNorm *nn.RMSNorm `gguf:"post_attention_norm"`
MLPNorm *nn.RMSNorm `gguf:"ffn_norm"`
MLP *MLP
PostMLPNorm *nn.RMSNorm `gguf:"post_ffw_norm"`
}
func (l *Layer) Forward(ctx ml.Context, hiddenState, positionIDs, outputs ml.Tensor, cache kvcache.Cache, opts *Options) ml.Tensor {
residual := hiddenState
hiddenState = l.AttentionNorm.Forward(ctx, hiddenState, opts.eps)
hiddenState = l.SelfAttention.Forward(ctx, hiddenState, positionIDs, cache, opts)
hiddenState = l.PostAttentionNorm.Forward(ctx, hiddenState, opts.eps)
// In the final layer (outputs != nil), optimize by pruning to just the token positions
// we need logits for.
if outputs != nil {
hiddenState = hiddenState.Rows(ctx, outputs)
residual = residual.Rows(ctx, outputs)
}
hiddenState = hiddenState.Add(ctx, residual)
residual = hiddenState
hiddenState = l.MLPNorm.Forward(ctx, hiddenState, opts.eps)
hiddenState = l.MLP.Forward(ctx, hiddenState, opts)
hiddenState = l.PostMLPNorm.Forward(ctx, hiddenState, opts.eps)
return hiddenState.Add(ctx, residual)
}
func (m *Model) Forward(ctx ml.Context, batch input.Batch) (ml.Tensor, error) {
positions, err := ctx.Input().FromIntSlice(batch.Positions, len(batch.Positions))
if err != nil {
return nil, err
}
outputs, err := ctx.Input().FromIntSlice(batch.Outputs, len(batch.Outputs))
if err != nil {
return nil, err
}
hiddenState := m.TokenEmbedding.Forward(ctx, batch.Inputs)
hiddenState = hiddenState.Scale(ctx, math.Sqrt(float64(m.Options.hiddenSize)))
if len(m.Layers) == gemma27BLayerCount {
m.Options.largeModelScaling = true
}
for i, layer := range m.Layers {
cacheType := i % 2
m.Cache.SetLayer(i)
wc := m.Cache.(*kvcache.WrapperCache)
wc.SetLayerType(cacheType)
var lastLayerOutputs ml.Tensor
if i == len(m.Layers)-1 {
lastLayerOutputs = outputs
}
hiddenState = layer.Forward(ctx, hiddenState, positions, lastLayerOutputs, m.Cache, m.Options)
}
hiddenState = m.OutputNorm.Forward(ctx, hiddenState, m.eps)
hiddenState = m.Output.Forward(ctx, hiddenState)
// final logit softcap
hiddenState = hiddenState.Scale(ctx, 1.0/float64(m.Options.finalLogitSoftcap))
hiddenState = hiddenState.Tanh(ctx)
return hiddenState.Scale(ctx, float64(m.Options.finalLogitSoftcap)), nil
}
func init() {
model.Register("gemma2", New)
}