nomic-embed-text:v2: model implementation (#13162)

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nicole pardal 2025-12-09 14:24:51 -08:00 committed by GitHub
parent 2bccf8c624
commit 76f88caf43
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3 changed files with 304 additions and 18 deletions

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@ -202,6 +202,8 @@ func ConvertModel(fsys fs.FS, f *os.File) error {
conv = &qwen3VLModel{}
case "BertModel":
conv = &bertModel{}
case "NomicBertModel", "NomicBertMoEModel":
conv = &nomicbertModel{}
case "CohereForCausalLM":
conv = &commandrModel{}
case "GptOssForCausalLM":

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@ -0,0 +1,213 @@
package convert
import (
"cmp"
"encoding/json"
"io/fs"
"path/filepath"
"slices"
"strings"
"github.com/ollama/ollama/fs/ggml"
)
type nomicbertModel struct {
ModelParameters
NLayers uint32 `json:"n_layers"`
NumHiddenLayers uint32 `json:"num_hidden_layers"`
MaxPositionEmbeddings uint32 `json:"max_position_embeddings"`
HiddenSize uint32 `json:"hidden_size"`
IntermediateSize uint32 `json:"intermediate_size"`
NumAttentionHeads uint32 `json:"num_attention_heads"`
NumKeyValueHeads uint32 `json:"num_key_value_heads"`
LayerNormEPS float32 `json:"layer_norm_eps"`
LayerNormEpsilon float32 `json:"layer_norm_epsilon"`
RopeFreqBase float32 `json:"rope_theta"`
normalizeEmbeddings bool
PoolingType uint32
// MoE parameters (only present in v2 models)
NumExperts uint32 `json:"num_local_experts"`
NumExpertsUsed uint32 `json:"num_experts_per_tok"`
MoEEveryNLayers uint32 `json:"moe_every_n_layers"`
}
var (
_ ModelConverter = (*nomicbertModel)(nil)
_ moreParser = (*nomicbertModel)(nil)
)
func (p *nomicbertModel) parseMore(fsys fs.FS) error {
bts, err := fs.ReadFile(fsys, "modules.json")
if err != nil {
return err
}
var modules []struct {
Type string `json:"type"`
Path string `json:"path"`
}
if err := json.Unmarshal(bts, &modules); err != nil {
return err
}
var pooling string
for _, m := range modules {
switch m.Type {
case "sentence_transformers.models.Pooling":
pooling = m.Path
case "sentence_transformers.models.Normalize":
p.normalizeEmbeddings = true
}
}
if pooling != "" {
bts, err := fs.ReadFile(fsys, filepath.Join(pooling, "config.json"))
if err != nil {
return err
}
var pc struct {
PoolingModeCLSToken bool `json:"pooling_mode_cls_token"`
PoolingModeMeanTokens bool `json:"pooling_mode_mean_tokens"`
}
if err := json.Unmarshal(bts, &pc); err != nil {
return err
}
if pc.PoolingModeMeanTokens {
p.PoolingType = 1
} else if pc.PoolingModeCLSToken {
p.PoolingType = 2
}
}
return nil
}
func (p *nomicbertModel) KV(t *Tokenizer) ggml.KV {
kv := p.ModelParameters.KV(t)
// Determine architecture based on MoE parameters (following qwen3 pattern)
arch := "nomic-bert"
if p.MoEEveryNLayers > 0 {
arch += "-moe"
}
kv["general.architecture"] = arch
kv["attention.causal"] = false
kv["pooling_type"] = p.PoolingType
kv["normalize_embeddings"] = p.normalizeEmbeddings
kv["block_count"] = cmp.Or(p.NLayers, p.NumHiddenLayers)
if contextLength := p.MaxPositionEmbeddings; contextLength > 0 {
kv["context_length"] = contextLength
}
if embeddingLength := p.HiddenSize; embeddingLength > 0 {
kv["embedding_length"] = p.HiddenSize
}
if feedForwardLength := p.IntermediateSize; feedForwardLength > 0 {
kv["feed_forward_length"] = p.IntermediateSize
}
if headCount := p.NumAttentionHeads; headCount > 0 {
kv["attention.head_count"] = p.NumAttentionHeads
}
if kvHeadCount := p.NumKeyValueHeads; kvHeadCount > 0 {
kv["attention.head_count_kv"] = p.NumKeyValueHeads
}
if layerNormEpsilon := cmp.Or(p.LayerNormEPS, p.LayerNormEpsilon); layerNormEpsilon > 0 {
kv["attention.layer_norm_epsilon"] = layerNormEpsilon
}
if p.RopeFreqBase > 0 {
kv["rope.freq_base"] = p.RopeFreqBase
}
// MoE specific parameters (only if MoE is enabled)
if p.NumExperts > 0 {
kv["expert_count"] = p.NumExperts
}
if p.NumExpertsUsed > 0 {
kv["expert_used_count"] = p.NumExpertsUsed
}
if p.MoEEveryNLayers > 0 {
kv["moe_every_n_layers"] = p.MoEEveryNLayers
}
kv["tokenizer.ggml.model"] = "bert"
kv["tokenizer.ggml.token_type_count"] = uint32(2)
// convert to phantom space tokens
for i, e := range t.Tokens {
switch {
case strings.HasPrefix(e, "[") && strings.HasSuffix(e, "]"):
// noop - keep special tokens as-is
case strings.HasPrefix(e, "##"):
t.Tokens[i] = e[2:]
default:
t.Tokens[i] = "\u2581" + e
}
}
kv["tokenizer.ggml.tokens"] = t.Tokens
return kv
}
func (p *nomicbertModel) Tensors(ts []Tensor) []*ggml.Tensor {
out := make([]*ggml.Tensor, 0, len(ts))
for _, t := range ts {
if slices.Contains([]string{
"embeddings.position_ids",
"pooler.dense.weight",
"pooler.dense.bias",
}, t.Name()) {
continue
}
out = append(out, &ggml.Tensor{
Name: t.Name(),
Kind: t.Kind(),
Shape: t.Shape(),
WriterTo: t,
})
}
return out
}
func (nomicbertModel) Replacements() []string {
return []string{
"encoder.layer", "blk",
"encoder.layers", "blk",
"embeddings.word_embeddings", "token_embd",
"embeddings.token_type_embeddings", "token_types",
"embeddings.LayerNorm", "token_embd_norm",
"attention.self.qkv", "attn_qkv",
"attention.output.dense", "attn_output",
"attention.output.LayerNorm", "attn_output_norm",
"mlp.up", "ffn_up",
"mlp.down", "ffn_down",
"mlp.router", "ffn_gate_inp",
"mlp.experts.up", "ffn_up_exps",
"mlp.experts.down", "ffn_down_exps",
"intermediate.dense", "ffn_up",
"output.dense", "ffn_down",
"output.LayerNorm", "layer_output_norm",
}
}

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@ -34,19 +34,23 @@ type Options struct {
poolingType pooling.Type
normalize bool
ropeFreqBase float32
// MoE specific options (used by v2 / MoE models only)
numExperts int
numExpertsUsed int
moeEveryNLayers int
}
func (o Options) applyRotaryPositionEmbeddings(ctx ml.Context, states, positions ml.Tensor) ml.Tensor {
return nn.RoPE(ctx, states, positions, o.headDim, o.ropeFreqBase, 1.0, rope.WithTypeNeoX())
}
// Single Encoder Layer
type EncoderLayer struct {
*Attention
AttentionNorm *nn.LayerNorm `gguf:"attn_output_norm"`
*MLP
FeedForward FeedForward
MLPNorm *nn.LayerNorm `gguf:"layer_output_norm"`
}
@ -56,12 +60,63 @@ type Attention struct {
Output *nn.Linear `gguf:"attn_output"`
}
type MLP struct {
type FeedForward interface {
Forward(ml.Context, ml.Tensor, *Options) ml.Tensor
}
type dense struct {
Gate *nn.Linear `gguf:"ffn_gate"`
Up *nn.Linear `gguf:"ffn_up"`
Down *nn.Linear `gguf:"ffn_down"`
}
func (mlp *dense) Forward(ctx ml.Context, hiddenStates ml.Tensor, _ *Options) ml.Tensor {
hidden := mlp.Gate.Forward(ctx, hiddenStates).SILU(ctx, mlp.Up.Forward(ctx, hiddenStates))
return mlp.Down.Forward(ctx, hidden)
}
// denseGELU implements MLP with GELU activation for v2 MoE dense layers
type denseGELU struct {
Up *nn.Linear `gguf:"ffn_up"`
Down *nn.Linear `gguf:"ffn_down"`
}
func (mlp *denseGELU) Forward(ctx ml.Context, hiddenStates ml.Tensor, _ *Options) ml.Tensor {
return mlp.Down.Forward(ctx, mlp.Up.Forward(ctx, hiddenStates).GELU(ctx))
}
// sparse implements MoE with expert routing
type sparse struct {
Router *nn.Linear `gguf:"ffn_gate_inp"`
Up *nn.LinearBatch `gguf:"ffn_up_exps"`
Down *nn.LinearBatch `gguf:"ffn_down_exps"`
}
func (moe *sparse) Forward(ctx ml.Context, hiddenStates ml.Tensor, opts *Options) ml.Tensor {
hiddenDim, sequenceLength, batchSize := hiddenStates.Dim(0), hiddenStates.Dim(1), hiddenStates.Dim(2)
hiddenStates = hiddenStates.Reshape(ctx, hiddenDim, sequenceLength*batchSize)
routerLogits := moe.Router.Forward(ctx, hiddenStates)
routingWeights := routerLogits.Softmax(ctx)
selectedExperts := routingWeights.TopK(ctx, opts.numExpertsUsed)
routingWeights = routingWeights.Reshape(ctx, 1, opts.numExperts, hiddenStates.Dim(1)).Rows(ctx, selectedExperts)
hiddenStates = hiddenStates.Reshape(ctx, hiddenStates.Dim(0), 1, hiddenStates.Dim(1))
hiddenStates = moe.Up.Forward(ctx, hiddenStates, selectedExperts).GELU(ctx)
experts := moe.Down.Forward(ctx, hiddenStates, selectedExperts)
experts = experts.Mul(ctx, routingWeights)
nextStates := experts.View(ctx, 0, experts.Dim(0), experts.Stride(2), experts.Dim(2))
for i := 1; i < opts.numExpertsUsed; i++ {
nextStates = nextStates.Add(ctx, experts.View(ctx, i*experts.Stride(1), experts.Dim(0), experts.Stride(2), experts.Dim(2)))
}
return nextStates
}
func (m *Model) Forward(ctx ml.Context, batch input.Batch) (ml.Tensor, error) {
hiddenStates := m.TokenEmbedding.Forward(ctx, batch.Inputs)
@ -92,7 +147,7 @@ func (e *EncoderLayer) Forward(ctx ml.Context, hiddenStates ml.Tensor, positions
hiddenStates = e.AttentionNorm.Forward(ctx, hiddenStates, opts.eps)
residual = hiddenStates
hiddenStates = e.MLP.Forward(ctx, hiddenStates)
hiddenStates = e.FeedForward.Forward(ctx, hiddenStates, opts)
hiddenStates = hiddenStates.Add(ctx, residual)
hiddenStates = e.MLPNorm.Forward(ctx, hiddenStates, opts.eps)
@ -118,12 +173,6 @@ func (a *Attention) Forward(ctx ml.Context, hiddenStates ml.Tensor, positions ml
return a.Output.Forward(ctx, attention)
}
func (m *MLP) Forward(ctx ml.Context, hiddenStates ml.Tensor) ml.Tensor {
hidden := m.Gate.Forward(ctx, hiddenStates).SILU(ctx, m.Up.Forward(ctx, hiddenStates))
return m.Down.Forward(ctx, hidden)
}
func New(c fs.Config) (model.Model, error) {
hiddenSize := int(c.Uint("embedding_length"))
numHeads := int(c.Uint("attention.head_count"))
@ -152,17 +201,37 @@ func New(c fs.Config) (model.Model, error) {
false,
)
blockCount := int(c.Uint("block_count"))
moeEveryNLayers := int(c.Uint("moe_every_n_layers", 0))
layers := make([]EncoderLayer, blockCount)
for i := range layers {
if moeEveryNLayers > 0 {
// Layer uses MoE if (i+1) % moe_every_n_layers == 0
if (i+1)%moeEveryNLayers == 0 {
layers[i].FeedForward = &sparse{}
} else {
layers[i].FeedForward = &denseGELU{}
}
} else {
layers[i].FeedForward = &dense{}
}
}
return &Model{
TextProcessor: processor,
Layers: make([]EncoderLayer, c.Uint("block_count")),
Layers: layers,
Options: Options{
hiddenSize: hiddenSize,
numHeads: numHeads,
headDim: headDim,
eps: c.Float("attention.layer_norm_epsilon"),
poolingType: pooling.Type(c.Uint("pooling_type")),
normalize: c.Bool("normalize_embeddings", false),
ropeFreqBase: c.Float("rope.freq_base", 1000.0),
hiddenSize: hiddenSize,
numHeads: numHeads,
headDim: headDim,
eps: c.Float("attention.layer_norm_epsilon"),
poolingType: pooling.Type(c.Uint("pooling_type")),
normalize: c.Bool("normalize_embeddings", false),
ropeFreqBase: c.Float("rope.freq_base", 1000.0),
numExperts: int(c.Uint("expert_count")),
numExpertsUsed: int(c.Uint("expert_used_count")),
moeEveryNLayers: moeEveryNLayers,
},
}, nil
}
@ -170,4 +239,6 @@ func New(c fs.Config) (model.Model, error) {
func init() {
model.Register("nomic-bert", New)
model.Register("nomic-bert_embed", New)
model.Register("nomic-bert-moe", New)
model.Register("nomic-bert-moe_embed", New)
}