feat: uneven splits (#11048)

The current splitDim function only operates on tensors that are split evenly which isn't always the case, e.g. a QKV tensor. This change allows the function to be used for arbitrary splits

convert/convert_qwen25vl.go

@@ -65,17 +65,17 @@ func (q *qwen25VLModel) Tensors(ts []Tensor) []*ggml.Tensor {
 	for _, t := range ts {
 		if strings.Contains(t.Name(), "patch_embed.proj") {
 			for t := range splitDim(t, 2,
-				strings.NewReplacer("patch_embed.proj", "patch_embd_0"),
-				strings.NewReplacer("patch_embed.proj", "patch_embd_1"),
+				split{Replacer: strings.NewReplacer("patch_embed.proj", "patch_embd_0")},
+				split{Replacer: strings.NewReplacer("patch_embed.proj", "patch_embd_1")},
 			) {
 				t.Shape = slices.DeleteFunc(t.Shape, func(i uint64) bool { return i == 1 })
 				out = append(out, t)
 			}
 		} else if strings.Contains(t.Name(), "attn.qkv") {
 			out = append(out, slices.Collect(splitDim(t, 0,
-				strings.NewReplacer("attn.qkv", "attn_q"),
-				strings.NewReplacer("attn.qkv", "attn_k"),
-				strings.NewReplacer("attn.qkv", "attn_v"),
+				split{Replacer: strings.NewReplacer("attn.qkv", "attn_q")},
+				split{Replacer: strings.NewReplacer("attn.qkv", "attn_k")},
+				split{Replacer: strings.NewReplacer("attn.qkv", "attn_v")},
 			))...)
 		} else {
 			out = append(out, &ggml.Tensor{

convert/tensor.go

 package convert
 
 import (
+	"cmp"
 	"iter"
 	"slices"
 	"strings"
 
-	"github.com/ollama/ollama/fs/ggml"
 	"github.com/pdevine/tensor"
 	"github.com/pdevine/tensor/native"
+
+	"github.com/ollama/ollama/fs/ggml"
 )
 
+type split struct {
+	*strings.Replacer
+	dim int
+
+	// fn is an optional function to apply to the tensor after slicing
+	fn func(tensor.Tensor) (tensor.Tensor, error)
+}
+
 // splitDim splits a tensor along a specified dimension into multiple tensors. The dimension
-// is split evenly based on the number of replacers provided.
-func splitDim(t Tensor, dim int, replacers ...*strings.Replacer) iter.Seq[*ggml.Tensor] {
+// is split evenly based on the number of replacers provided unless a specific count is given.
+func splitDim(t Tensor, dim int, splits ...split) iter.Seq[*ggml.Tensor] {
 	return func(yield func(*ggml.Tensor) bool) {
-		for i, replacer := range replacers {
+		var offset int
+		for _, split := range splits {
+			t := t.Clone()
 			shape := slices.Clone(t.Shape())
-			shape[dim] = shape[dim] / uint64(len(replacers))
+			shape[dim] = cmp.Or(uint64(split.dim), shape[dim]/uint64(len(splits)))
 
 			slice := slices.Repeat([]tensor.Slice{nil}, len(shape))
-			slice[dim] = tensor.S(i*int(shape[dim]), (i+1)*int(shape[dim]))
+			slice[dim] = tensor.S(offset, offset+int(shape[dim]))
+			offset += int(shape[dim])
 
-			tt := t.Clone()
-			tt.SetRepacker(func(_ string, data []float32, shape []uint64) ([]float32, error) {
+			t.SetRepacker(func(_ string, data []float32, shape []uint64) ([]float32, error) {
 				dims := make([]int, len(shape))
 				for i := range shape {
 					dims[i] = int(shape[i])
 				}
 
-				var t tensor.Tensor = tensor.New(tensor.WithShape(dims...), tensor.WithBacking(data))
-				t, err := t.Slice(slice...)
+				var tt tensor.Tensor = tensor.New(tensor.WithShape(dims...), tensor.WithBacking(data))
+				tt, err := tt.Slice(slice...)
 				if err != nil {
 					return nil, err
 				}
 
-				t = tensor.Materialize(t)
+				tt = tensor.Materialize(tt)
+
+				if split.fn != nil {
+					tt, err = split.fn(tt)
+					if err != nil {
+						return nil, err
+					}
+				}
+
 				// flatten tensor so it can be written as a vector
-				if err := t.Reshape(t.Shape().TotalSize()); err != nil {
+				if err := tt.Reshape(tt.Shape().TotalSize()); err != nil {
 					return nil, err
 				}
 
-				return native.VectorF32(t.(*tensor.Dense))
+				return native.VectorF32(tt.(*tensor.Dense))
 			})
 
 			if !yield(&ggml.Tensor{
-				Name:     replacer.Replace(t.Name()),
+				Name:     split.Replace(t.Name()),
 				Kind:     t.Kind(),
 				Shape:    shape,
-				WriterTo: tt,
+				WriterTo: t,
 			}) {
 				break
 			}

convert/tensor_test.go

+package convert
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"iter"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/pdevine/tensor"
+)
+
+type fakeTensor struct {
+	name  string
+	shape []uint64
+	data  []float32
+
+	repacker Repacker
+}
+
+func (f fakeTensor) Name() string {
+	return f.name
+}
+
+func (f fakeTensor) Shape() []uint64 {
+	return f.shape
+}
+
+func (f fakeTensor) Kind() uint32 {
+	return 0
+}
+
+func (f *fakeTensor) SetRepacker(fn Repacker) {
+	f.repacker = fn
+}
+
+func (f fakeTensor) Clone() Tensor {
+	return &fakeTensor{
+		name:     f.name,
+		shape:    slices.Clone(f.shape),
+		data:     slices.Clone(f.data),
+		repacker: f.repacker,
+	}
+}
+
+func (f fakeTensor) WriteTo(w io.Writer) (n int64, err error) {
+	data := f.data
+	if f.repacker != nil {
+		data, err = f.repacker(f.name, data, f.shape)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	if err := binary.Write(w, binary.LittleEndian, data); err != nil {
+		return 0, err
+	}
+
+	return int64(len(data) * 4), nil
+}
+
+func mul(shape []uint64) int {
+	n := 1
+	for _, dim := range shape {
+		n *= int(dim)
+	}
+	return n
+}
+
+func TestSplitDim(t *testing.T) {
+	r := fakeTensor{
+		name:  "a.b",
+		shape: []uint64{3, 4},
+		data:  []float32{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11},
+	}
+
+	t.Run("no split", func(t *testing.T) {
+		for tt := range splitDim(&r, 0, split{Replacer: strings.NewReplacer("a", "x")}) {
+			if tt.Name != "x.b" {
+				t.Fatalf("expected name 'x', got '%s'", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{3, 4}) {
+				t.Fatalf("expected shape [3, 4], got %v", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}) {
+				t.Fatalf("expected data [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], got %v", f32s)
+			}
+		}
+	})
+
+	t.Run("even split", func(t *testing.T) {
+		next, stop := iter.Pull(splitDim(&r, 1,
+			split{Replacer: strings.NewReplacer("a", "x")},
+			split{Replacer: strings.NewReplacer("b", "y")},
+		))
+		defer stop()
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "x.b" {
+				t.Fatal("expected name 'x.b', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{3, 2}) {
+				t.Fatal("expected shape [3, 2], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{0, 1, 4, 5, 8, 9}) {
+				t.Fatal("expected data [0, 1, 4, 5, 8, 9], got", f32s)
+			}
+		}
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "a.y" {
+				t.Fatal("expected name 'a.y', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{3, 2}) {
+				t.Fatal("expected shape [3, 2], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{2, 3, 6, 7, 10, 11}) {
+				t.Fatal("expected data [2, 3, 6, 7, 10, 11], got", f32s)
+			}
+		}
+	})
+
+	t.Run("uneven split", func(t *testing.T) {
+		next, stop := iter.Pull(splitDim(&r, 0,
+			split{Replacer: strings.NewReplacer("a", "x"), dim: 2},
+			split{Replacer: strings.NewReplacer("b", "y"), dim: 1},
+		))
+		defer stop()
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "x.b" {
+				t.Fatal("expected name 'x.b', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{2, 4}) {
+				t.Fatal("expected shape [2, 4], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{0, 1, 2, 3, 4, 5, 6, 7}) {
+				t.Fatal("expected data [0, 1, 2, 3, 4, 5, 6, 7], got", f32s)
+			}
+		}
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "a.y" {
+				t.Fatal("expected name 'a.y', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{1, 4}) {
+				t.Fatal("expected shape [1, 4], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{8, 9, 10, 11}) {
+				t.Fatal("expected data [8, 9, 10, 11], got", f32s)
+			}
+		}
+	})
+
+	t.Run("split with transpose", func(t *testing.T) {
+		next, stop := iter.Pull(splitDim(&r, 1,
+			split{Replacer: strings.NewReplacer("a", "x")},
+			split{Replacer: strings.NewReplacer("b", "y"), fn: func(tt tensor.Tensor) (tensor.Tensor, error) {
+				return tensor.Transpose(tt, 1, 0)
+			}},
+		))
+		defer stop()
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "x.b" {
+				t.Fatal("expected name 'x.b', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{3, 2}) {
+				t.Fatal("expected shape [3, 2], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{0, 1, 4, 5, 8, 9}) {
+				t.Fatal("expected data [0, 1, 4, 5, 8, 9], got", f32s)
+			}
+		}
+
+		{
+			tt, ok := next()
+			if !ok {
+				t.Fatal("expected at least one split")
+			}
+
+			if tt.Name != "a.y" {
+				t.Fatal("expected name 'a.y', got", tt.Name)
+			}
+
+			if !slices.Equal(tt.Shape, []uint64{3, 2}) {
+				t.Fatal("expected shape [3, 2], got", tt.Shape)
+			}
+
+			var b bytes.Buffer
+			if _, err := tt.WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			f32s := make([]float32, mul(tt.Shape))
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.Equal(f32s, []float32{2, 6, 10, 3, 7, 11}) {
+				t.Fatal("expected data [2, 6, 10, 3, 7, 11], got", f32s)
+			}
+		}
+	})
+}