add gemma vision encoder

model/models/gemma3/model_vision.go

@@ -0,0 +1,171 @@
+package gemma3
+
+import (
+	"math"
+	"slices"
+
+	"github.com/ollama/ollama/ml"
+	"github.com/ollama/ollama/ml/nn"
+)
+
+var batchSize int = 1
+
+type VisionSelfAttention 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 *VisionSelfAttention) Forward(ctx ml.Context, hiddenState ml.Tensor, opts *VisionModelOptions) ml.Tensor {
+	headDim := opts.hiddenSize / opts.numHeads
+
+	query := sa.Query.Forward(ctx, hiddenState)
+	key := sa.Key.Forward(ctx, hiddenState)
+	value := sa.Value.Forward(ctx, hiddenState)
+
+	query = query.Reshape(ctx, headDim, opts.numHeads, query.Dim(1), batchSize).Permute(ctx, 0, 2, 1, 3)
+	key = key.Reshape(ctx, headDim, opts.numHeads, key.Dim(1), batchSize).Permute(ctx, 0, 2, 1, 3)
+	value = value.Reshape(ctx, headDim, opts.numHeads, value.Dim(1), batchSize).Permute(ctx, 1, 2, 0, 3).Contiguous(ctx)
+
+	scores := key.Mulmat(ctx, query)
+	scores = scores.Scale(ctx, 1.0/math.Sqrt(float64(headDim)))
+	scores = scores.Softmax(ctx)
+
+	attention := value.Mulmat(ctx, scores)
+	attention = attention.Reshape(ctx, headDim, attention.Dim(1), opts.numHeads, batchSize)
+	attention = attention.Permute(ctx, 0, 2, 1, 3).Contiguous(ctx)
+	attention = attention.Reshape(ctx, opts.hiddenSize, attention.Dim(2), batchSize)
+
+	hiddenState = sa.Output.Forward(ctx, attention)
+	return hiddenState
+}
+
+type VisionMLP struct {
+	FC1 *nn.Linear `gguf:"fc1"`
+	FC2 *nn.Linear `gguf:"fc2"`
+}
+
+func (mlp *VisionMLP) Forward(ctx ml.Context, hiddenState ml.Tensor, opts *VisionModelOptions) ml.Tensor {
+	hiddenState = mlp.FC1.Forward(ctx, hiddenState).GELU(ctx)
+	hiddenState = mlp.FC2.Forward(ctx, hiddenState)
+	return hiddenState
+}
+
+type VisionEncoderLayer struct {
+	LayerNorm1    *nn.LayerNorm        `gguf:"layer_norm1"`
+	SelfAttention *VisionSelfAttention
+
+	LayerNorm2 *nn.LayerNorm `gguf:"layer_norm2"`
+	MLP        *VisionMLP    `gguf:"mlp"`
+}
+
+func (e *VisionEncoderLayer) Forward(ctx ml.Context, hiddenState ml.Tensor, opts *VisionModelOptions) ml.Tensor {
+	residual := hiddenState
+
+	// self attention
+	hiddenState = e.LayerNorm1.Forward(ctx, hiddenState, opts.eps)
+	hiddenState = e.SelfAttention.Forward(ctx, hiddenState, opts)
+	hiddenState = hiddenState.Add(ctx, residual)
+	residual = hiddenState
+
+	// feed forward
+	hiddenState = e.LayerNorm2.Forward(ctx, hiddenState, opts.eps)
+	hiddenState = e.MLP.Forward(ctx, hiddenState, opts)
+	return hiddenState.Add(ctx, residual)
+}
+
+type VisionEncoder struct {
+	Layers []VisionEncoderLayer
+}
+
+func (e *VisionEncoder) Forward(ctx ml.Context, hiddenState ml.Tensor, intermediateLayersIndices []uint32, opts *VisionModelOptions) (ml.Tensor, []ml.Tensor) {
+	var intermediateHiddenStates []ml.Tensor
+	for i, layer := range e.Layers {
+		if slices.Contains(intermediateLayersIndices, uint32(i)) {
+			intermediateHiddenStates = append(intermediateHiddenStates, hiddenState.Reshape(ctx, append([]int{1}, hiddenState.Shape()...)...))
+		}
+
+		hiddenState = layer.Forward(ctx, hiddenState, opts)
+	}
+
+	return hiddenState, intermediateHiddenStates
+}
+
+type PrecomputedAspectRatioEmbedding struct {
+	Embedding *nn.Embedding
+	Gate      ml.Tensor `gguf:"gate"`
+}
+
+func (e *PrecomputedAspectRatioEmbedding) Forward(ctx ml.Context, hiddenState ml.Tensor, aspectRatioIDs ml.Tensor, opts *VisionModelOptions) ml.Tensor {
+	embeddings := e.Embedding.Forward(ctx, aspectRatioIDs)
+	embeddings = embeddings.Reshape(ctx, opts.hiddenSize, 1, opts.numTiles)
+	if e.Gate != nil {
+		embeddings = embeddings.Mul(ctx, e.Gate)
+	}
+
+	return hiddenState.Add(ctx, embeddings)
+}
+
+type PrecomputedPositionEmbedding struct {
+	PositionEmbedding     *nn.Embedding `gguf:"position_embd"`
+	PositionEmbeddingGate ml.Tensor     `gguf:"position_embd.gate"`
+}
+
+func (e *PrecomputedPositionEmbedding) Forward(ctx ml.Context, hiddenState, positionIDs ml.Tensor, numPositions int, opts *VisionModelOptions) ml.Tensor {
+	positionEmbedding := e.PositionEmbedding.Forward(ctx, positionIDs)
+	if e.PositionEmbeddingGate != nil {
+		positionEmbedding = positionEmbedding.Mul(ctx, e.PositionEmbeddingGate)
+	}
+
+	return hiddenState.Add(ctx, positionEmbedding)
+}
+
+type VisionModelOptions struct {
+	hiddenSize, numHeads, numTiles int
+	imageSize, patchSize           int
+	eps                            float32
+}
+
+type VisionModel struct {
+	PatchEmbedding    *nn.Conv2D    `gguf:"patch_embedding"`
+	PositionEmbedding *nn.Embedding `gguf:"position_embedding"`
+	PostLayerNorm     *nn.LayerNorm `gguf:"post_layernorm"`
+
+	Encoder *VisionEncoder `gguf:"blk"`
+
+	*VisionModelOptions
+}
+
+func (m *VisionModel) Forward(ctx ml.Context, pixelValues, positionIDs ml.Tensor) ml.Tensor {
+	numPatches := (m.imageSize / m.patchSize) * (m.imageSize / m.patchSize)
+
+	hiddenState := m.PatchEmbedding.Forward(ctx, pixelValues, m.patchSize, m.patchSize, 0, 0, 1, 1)
+	hiddenState = hiddenState.Reshape(ctx, numPatches, m.hiddenSize)
+	hiddenState = hiddenState.Permute(ctx, 1, 0, 2, 3).Contiguous(ctx)
+
+	positions := m.PositionEmbedding.Forward(ctx, positionIDs)
+	hiddenState = hiddenState.Add(ctx, positions)
+
+	for _, layer := range m.Encoder.Layers {
+		hiddenState = layer.Forward(ctx, hiddenState, m.VisionModelOptions)
+	}
+
+	hiddenState = m.PostLayerNorm.Forward(ctx, hiddenState, m.eps)
+	return hiddenState
+}
+
+func newVisionModel(c ml.Config) *VisionModel {
+	return &VisionModel{
+		Encoder: &VisionEncoder{Layers: make([]VisionEncoderLayer, c.Uint("vision.block_count"))},
+		VisionModelOptions: &VisionModelOptions{
+			hiddenSize: int(c.Uint("vision.embedding_length")),
+			numHeads:   int(c.Uint("vision.attention.head_count")),
+
+			imageSize: int(c.Uint("vision.image_size")),
+			patchSize: int(c.Uint("vision.patch_size")),
+
+			eps: c.Float("vision.attention.layer_norm_epsilon"),
+		},
+	}
+}