fix tensor merge (#13053)

convert/tensor.go

@@ -2,10 +2,12 @@ package convert
 
 import (
 	"cmp"
+	"errors"
 	"io"
 	"iter"
 	"path"
 	"slices"
+	"strconv"
 	"strings"
 
 	"github.com/pdevine/tensor"
@@ -94,6 +96,26 @@ func mergeTensors(unmatched []Tensor, merges ...merge) (out []*ggml.Tensor, _ []
 			return matched
 		})
 
+		slices.SortStableFunc(matched, func(a, b Tensor) int {
+			x := strings.Split(a.Name(), ".")
+			y := strings.Split(b.Name(), ".")
+			if len(x) != len(y) {
+				return cmp.Compare(len(x), len(y))
+			}
+
+			vals := make([]int, len(x))
+			for i := range x {
+				vals[i] = strings.Compare(x[i], y[i])
+				m, err := strconv.ParseInt(x[i], 0, 0)
+				n, err2 := strconv.ParseInt(y[i], 0, 0)
+				if errors.Join(err, err2) == nil {
+					vals[i] = cmp.Compare(m, n)
+				}
+			}
+
+			return cmp.Or(vals...)
+		})
+
 		if len(matched) > 0 {
 			out = append(out, &ggml.Tensor{
 				Name:     merges[i].name,

convert/tensor_test.go

@@ -3,8 +3,10 @@ package convert
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"io"
 	"iter"
+	"math/rand/v2"
 	"slices"
 	"strings"
 	"testing"
@@ -951,3 +953,45 @@ func TestMerge(t *testing.T) {
 		}
 	})
 }
+
+func TestMergeOrder(t *testing.T) {
+	for range 8 {
+		t.Run("", func(t *testing.T) {
+			tensors := make([]Tensor, 16)
+			for i := range tensors {
+				tensors[i] = &fakeTensor{
+					name:  fmt.Sprintf("layer.%d.weight", i),
+					shape: []uint64{1},
+					data:  []float32{float32(i)},
+				}
+			}
+
+			rand.Shuffle(len(tensors), func(i, j int) {
+				tensors[i], tensors[j] = tensors[j], tensors[i]
+			})
+
+			matched, unmatched := mergeTensors(tensors, merge{"layer.*.weight", "layer.weight"})
+			if len(unmatched) != 0 {
+				t.Error("expected no remaining tensors, got", len(unmatched))
+			}
+
+			if len(matched) != 1 {
+				t.Error("expected 1 merged tensor, got", len(matched))
+			}
+
+			var b bytes.Buffer
+			if _, err := matched[0].WriteTo(&b); err != nil {
+				t.Fatal(err)
+			}
+
+			var f32s [16]float32
+			if err := binary.Read(&b, binary.LittleEndian, &f32s); err != nil {
+				t.Fatal(err)
+			}
+
+			if !slices.IsSorted(f32s[:]) {
+				t.Errorf("merged tensor data is not in order: %+v", f32s)
+			}
+		})
+	}
+}