ml: add slice operation (#12870)

* slice

* chunk, chunksections
This commit is contained in:
Michael Yang
2025-11-13 13:28:21 -08:00
committed by GitHub
parent 482bec824f
commit b48083f33f
3 changed files with 773 additions and 1 deletions

View File

@@ -198,6 +198,10 @@ type Tensor interface {
Copy(ctx Context, t2 Tensor) Tensor
Duplicate(ctx Context) Tensor
Slice(ctx Context, dim, low, high, step int) Tensor
Chunk(ctx Context, dim int, size int) []Tensor
ChunkSections(ctx Context, dim int, sections ...int) []Tensor
TopK(ctx Context, k int) Tensor
Argsort(ctx Context) Tensor
Mean(ctx Context) Tensor

View File

@@ -1738,3 +1738,66 @@ func (t *Tensor) Clamp(ctx ml.Context, min, max float32) ml.Tensor {
t: C.ggml_clamp(ctx.(*Context).ctx, t.t, C.float(min), C.float(max)),
}
}
// Slice returns a view of the tensor sliced along dim from low to high in step steps.
// Slice panics if the dimension is invalid or the slice parameters are out of range.
// If dim=0 and step>1, the tensor is a copy rather than a view to ensure proper shape.
func (t *Tensor) Slice(ctx ml.Context, dim int, low, high, step int) ml.Tensor {
if dim < 0 || dim >= C.GGML_MAX_DIMS {
panic("invalid dimension")
} else if low < 0 || high > t.Dim(dim) || low >= high || step < 1 {
panic("invalid slice parameters")
}
if dim == 0 && step > 1 {
// dim=0,step>1 is a special case so handle it here first
return t.View(ctx,
low*t.Stride(0), 1,
step*t.Stride(0), (high-low+1)/step,
t.Stride(1), t.Dim(1),
// preserve dim 3 by merging it into dim 2
t.Stride(2), t.Dim(2)*t.Dim(3),
).Contiguous(ctx, (high-low+1)/step, t.Dim(1), t.Dim(2), t.Dim(3))
}
args := []int{
low * t.Stride(dim), t.Dim(0),
t.Stride(1), t.Dim(1),
t.Stride(2), t.Dim(2),
t.Stride(3), t.Dim(3),
}
if step == 1 {
args[dim*2+1] = high - low
return t.View(ctx, args[0], args[1:]...)
} else {
args[dim*2] = step * t.Stride(dim)
args[dim*2+1] = (high - low + 1) / step
return t.View(ctx, args[0], args[1:]...)
}
}
// Chunk the tensor into chunk sized tensors along dim. Each sub-tensor is a view of
// the original.
func (t *Tensor) Chunk(ctx ml.Context, dim, chunk int) []ml.Tensor {
sections := make([]int, 0, t.Dim(dim)/chunk+1)
for rest := t.Dim(dim); rest > 0; rest -= chunk {
sections = append(sections, min(chunk, rest))
}
return t.ChunkSections(ctx, dim, sections...)
}
// ChunkSections split the tensor into section sized tensors along dim. Each sub-tensor is a
// view of the original. The size of the dim must equal the sum of sections.
func (t *Tensor) ChunkSections(ctx ml.Context, dim int, sections ...int) []ml.Tensor {
var offset int
s := make([]ml.Tensor, len(sections))
for i, section := range sections {
s[i] = t.Slice(ctx, dim, offset, offset+section, 1)
offset += section
}
if offset != t.Dim(dim) {
panic("sections do not sum to tensor dimension")
}
return s
}

View File

@@ -2,6 +2,7 @@ package ggml
import (
"errors"
"fmt"
"os"
"testing"
@@ -368,10 +369,714 @@ func TestPermute(t *testing.T) {
for _, tt := range cases {
t.Run(tt.name, func(t *testing.T) {
ctx := setup(t)
got := tt.input(ctx).Permute(ctx, tt.shape...).Contiguous(ctx)
got := tt.input(ctx).Permute(ctx, tt.shape...)
got = got.Contiguous(ctx)
if diff := cmp.Diff(tt.want(ctx), got, EquateTensors(ctx)); diff != "" {
t.Errorf("Permute() result mismatch (-want +got):\n%s", diff)
}
})
}
}
func TestSlice(t *testing.T) {
cases := []struct {
dim int
low int
high int
step int
input func(ml.Context) ml.Tensor
want func(ml.Context) ml.Tensor
}{
{
dim: 0, low: 1, high: 3, step: 1,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
1, 2,
5, 6,
9, 10,
13, 14,
17, 18,
21, 22,
25, 26,
29, 30,
33, 34,
37, 38,
41, 42,
45, 46,
49, 50,
53, 54,
57, 58,
61, 62,
65, 66,
69, 70,
73, 74,
77, 78,
81, 82,
85, 86,
89, 90,
93, 94,
97, 98,
101, 102,
105, 106,
109, 110,
113, 114,
117, 118,
121, 122,
125, 126,
129, 130,
133, 134,
137, 138,
141, 142,
145, 146,
149, 150,
153, 154,
157, 158,
161, 162,
165, 166,
169, 170,
173, 174,
177, 178,
181, 182,
185, 186,
189, 190,
193, 194,
197, 198,
201, 202,
205, 206,
209, 210,
213, 214,
217, 218,
221, 222,
225, 226,
229, 230,
233, 234,
237, 238,
241, 242,
245, 246,
249, 250,
253, 254,
}, 2, 4, 4, 4)
},
},
{
dim: 1, low: 1, high: 3, step: 1,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
4, 5, 6, 7,
8, 9, 10, 11,
20, 21, 22, 23,
24, 25, 26, 27,
36, 37, 38, 39,
40, 41, 42, 43,
52, 53, 54, 55,
56, 57, 58, 59,
68, 69, 70, 71,
72, 73, 74, 75,
84, 85, 86, 87,
88, 89, 90, 91,
100, 101, 102, 103,
104, 105, 106, 107,
116, 117, 118, 119,
120, 121, 122, 123,
132, 133, 134, 135,
136, 137, 138, 139,
148, 149, 150, 151,
152, 153, 154, 155,
164, 165, 166, 167,
168, 169, 170, 171,
180, 181, 182, 183,
184, 185, 186, 187,
196, 197, 198, 199,
200, 201, 202, 203,
212, 213, 214, 215,
216, 217, 218, 219,
228, 229, 230, 231,
232, 233, 234, 235,
244, 245, 246, 247,
248, 249, 250, 251,
}, 4, 2, 4, 4)
},
},
{
dim: 2, low: 1, high: 3, step: 1,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
16, 17, 18, 19,
20, 21, 22, 23,
24, 25, 26, 27,
28, 29, 30, 31,
32, 33, 34, 35,
36, 37, 38, 39,
40, 41, 42, 43,
44, 45, 46, 47,
80, 81, 82, 83,
84, 85, 86, 87,
88, 89, 90, 91,
92, 93, 94, 95,
96, 97, 98, 99,
100, 101, 102, 103,
104, 105, 106, 107,
108, 109, 110, 111,
144, 145, 146, 147,
148, 149, 150, 151,
152, 153, 154, 155,
156, 157, 158, 159,
160, 161, 162, 163,
164, 165, 166, 167,
168, 169, 170, 171,
172, 173, 174, 175,
208, 209, 210, 211,
212, 213, 214, 215,
216, 217, 218, 219,
220, 221, 222, 223,
224, 225, 226, 227,
228, 229, 230, 231,
232, 233, 234, 235,
236, 237, 238, 239,
}, 4, 4, 2, 4)
},
},
{
dim: 3, low: 1, high: 3, step: 1,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
64, 65, 66, 67,
68, 69, 70, 71,
72, 73, 74, 75,
76, 77, 78, 79,
80, 81, 82, 83,
84, 85, 86, 87,
88, 89, 90, 91,
92, 93, 94, 95,
96, 97, 98, 99,
100, 101, 102, 103,
104, 105, 106, 107,
108, 109, 110, 111,
112, 113, 114, 115,
116, 117, 118, 119,
120, 121, 122, 123,
124, 125, 126, 127,
128, 129, 130, 131,
132, 133, 134, 135,
136, 137, 138, 139,
140, 141, 142, 143,
144, 145, 146, 147,
148, 149, 150, 151,
152, 153, 154, 155,
156, 157, 158, 159,
160, 161, 162, 163,
164, 165, 166, 167,
168, 169, 170, 171,
172, 173, 174, 175,
176, 177, 178, 179,
180, 181, 182, 183,
184, 185, 186, 187,
188, 189, 190, 191,
}, 4, 4, 4, 2)
},
},
{
dim: 0, low: 0, high: 4, step: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 2,
4, 6,
8, 10,
12, 14,
16, 18,
20, 22,
24, 26,
28, 30,
32, 34,
36, 38,
40, 42,
44, 46,
48, 50,
52, 54,
56, 58,
60, 62,
64, 66,
68, 70,
72, 74,
76, 78,
80, 82,
84, 86,
88, 90,
92, 94,
96, 98,
100, 102,
104, 106,
108, 110,
112, 114,
116, 118,
120, 122,
124, 126,
128, 130,
132, 134,
136, 138,
140, 142,
144, 146,
148, 150,
152, 154,
156, 158,
160, 162,
164, 166,
168, 170,
172, 174,
176, 178,
180, 182,
184, 186,
188, 190,
192, 194,
196, 198,
200, 202,
204, 206,
208, 210,
212, 214,
216, 218,
220, 222,
224, 226,
228, 230,
232, 234,
236, 238,
240, 242,
244, 246,
248, 250,
252, 254,
}, 2, 4, 4, 4)
},
},
{
dim: 1, low: 0, high: 4, step: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1, 2, 3,
8, 9, 10, 11,
16, 17, 18, 19,
24, 25, 26, 27,
32, 33, 34, 35,
40, 41, 42, 43,
48, 49, 50, 51,
56, 57, 58, 59,
64, 65, 66, 67,
72, 73, 74, 75,
80, 81, 82, 83,
88, 89, 90, 91,
96, 97, 98, 99,
104, 105, 106, 107,
112, 113, 114, 115,
120, 121, 122, 123,
128, 129, 130, 131,
136, 137, 138, 139,
144, 145, 146, 147,
152, 153, 154, 155,
160, 161, 162, 163,
168, 169, 170, 171,
176, 177, 178, 179,
184, 185, 186, 187,
192, 193, 194, 195,
200, 201, 202, 203,
208, 209, 210, 211,
216, 217, 218, 219,
224, 225, 226, 227,
232, 233, 234, 235,
240, 241, 242, 243,
248, 249, 250, 251,
}, 4, 2, 4, 4)
},
},
{
dim: 2, low: 0, high: 4, step: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1, 2, 3,
4, 5, 6, 7,
8, 9, 10, 11,
12, 13, 14, 15,
32, 33, 34, 35,
36, 37, 38, 39,
40, 41, 42, 43,
44, 45, 46, 47,
64, 65, 66, 67,
68, 69, 70, 71,
72, 73, 74, 75,
76, 77, 78, 79,
96, 97, 98, 99,
100, 101, 102, 103,
104, 105, 106, 107,
108, 109, 110, 111,
128, 129, 130, 131,
132, 133, 134, 135,
136, 137, 138, 139,
140, 141, 142, 143,
160, 161, 162, 163,
164, 165, 166, 167,
168, 169, 170, 171,
172, 173, 174, 175,
192, 193, 194, 195,
196, 197, 198, 199,
200, 201, 202, 203,
204, 205, 206, 207,
224, 225, 226, 227,
228, 229, 230, 231,
232, 233, 234, 235,
236, 237, 238, 239,
}, 4, 4, 2, 4)
},
},
{
dim: 3, low: 0, high: 4, step: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 4*4*4*4, 1, ml.DTypeF32).Reshape(ctx, 4, 4, 4, 4)
},
want: func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1, 2, 3,
4, 5, 6, 7,
8, 9, 10, 11,
12, 13, 14, 15,
16, 17, 18, 19,
20, 21, 22, 23,
24, 25, 26, 27,
28, 29, 30, 31,
32, 33, 34, 35,
36, 37, 38, 39,
40, 41, 42, 43,
44, 45, 46, 47,
48, 49, 50, 51,
52, 53, 54, 55,
56, 57, 58, 59,
60, 61, 62, 63,
128, 129, 130, 131,
132, 133, 134, 135,
136, 137, 138, 139,
140, 141, 142, 143,
144, 145, 146, 147,
148, 149, 150, 151,
152, 153, 154, 155,
156, 157, 158, 159,
160, 161, 162, 163,
164, 165, 166, 167,
168, 169, 170, 171,
172, 173, 174, 175,
176, 177, 178, 179,
180, 181, 182, 183,
184, 185, 186, 187,
188, 189, 190, 191,
}, 4, 4, 4, 2)
},
},
}
for _, tt := range cases {
name := fmt.Sprintf("dim=%d,low=%d,high=%d,step=%d", tt.dim, tt.low, tt.high, tt.step)
t.Run(name, func(t *testing.T) {
ctx := setup(t)
got := tt.input(ctx).Slice(ctx, tt.dim, tt.low, tt.high, tt.step)
got = got.Contiguous(ctx)
if diff := cmp.Diff(tt.want(ctx), got, EquateTensors(ctx)); diff != "" {
t.Errorf("Slice() result mismatch (-want +got):\n%s", diff)
}
})
}
}
func TestSplitSections(t *testing.T) {
cases := []struct {
dim int
sections []int
input func(ml.Context) ml.Tensor
want []func(ml.Context) ml.Tensor
}{
{
dim: 0, sections: []int{1, 1, 1},
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 3, 4)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{0, 3, 6, 9}, 1, 4)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{1, 4, 7, 10}, 1, 4)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{2, 5, 8, 11}, 1, 4)
},
},
},
{
dim: 1, sections: []int{1, 3},
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 3, 4)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{0, 1, 2}, 3, 1)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
3, 4, 5,
6, 7, 8,
9, 10, 11,
}, 3, 3)
},
},
},
{
dim: 0, sections: []int{2, 2},
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 4, 3)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1,
4, 5,
8, 9,
}, 2, 3)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
2, 3,
6, 7,
10, 11,
}, 2, 3)
},
},
},
{
dim: 1, sections: []int{1, 2},
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 4, 3)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{0, 1, 2, 3}, 4, 1)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
4, 5, 6, 7,
8, 9, 10, 11,
}, 4, 2)
},
},
},
}
for _, tt := range cases {
t.Run(fmt.Sprintf("sections=%v", tt.sections), func(t *testing.T) {
ctx := setup(t)
got := tt.input(ctx).ChunkSections(ctx, tt.dim, tt.sections...)
for i := range got {
got[i] = got[i].Contiguous(ctx)
}
ctx.Forward(got...).Compute(got...)
for i, want := range tt.want {
if diff := cmp.Diff(want(ctx), got[i], EquateTensors(ctx)); diff != "" {
t.Errorf("SplitSections() section %d mismatch (-want +got):\n%s", i, diff)
}
}
})
}
}
func TestChunk(t *testing.T) {
cases := []struct {
dim int
chunk int
input func(ml.Context) ml.Tensor
want []func(ml.Context) ml.Tensor
}{
{
dim: 0, chunk: 1,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 3, 4)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{0, 3, 6, 9}, 1, 4)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{1, 4, 7, 10}, 1, 4)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{2, 5, 8, 11}, 1, 4)
},
},
},
{
dim: 1, chunk: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 3, 4)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1, 2,
3, 4, 5,
}, 3, 2)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
6, 7, 8,
9, 10, 11,
}, 3, 2)
},
},
},
{
dim: 0, chunk: 2,
input: func(ctx ml.Context) ml.Tensor {
return ctx.Arange(0, 12, 1, ml.DTypeF32).Reshape(ctx, 3, 4)
},
want: []func(ml.Context) ml.Tensor{
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
0, 1,
3, 4,
6, 7,
9, 10,
}, 2, 4)
},
func(ctx ml.Context) ml.Tensor {
return ctx.FromFloats([]float32{
2,
5,
8,
11,
}, 1, 4)
},
},
},
}
for _, tt := range cases {
t.Run(fmt.Sprintf("dim=%d,chunk=%d", tt.dim, tt.chunk), func(t *testing.T) {
ctx := setup(t)
got := tt.input(ctx).Chunk(ctx, tt.dim, tt.chunk)
for i := range got {
got[i] = got[i].Contiguous(ctx)
}
ctx.Forward(got...).Compute(got...)
for i, want := range tt.want {
if diff := cmp.Diff(want(ctx), got[i], EquateTensors(ctx)); diff != "" {
t.Errorf("Split() section %d mismatch (-want +got):\n%s", i, diff)
}
}
})
}
}