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
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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
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
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
use {Ix, Ixs};
use error::{from_kind, ErrorKind, ShapeError};
pub use self::dim::*;
pub use self::axis::Axis;
pub use self::conversion::IntoDimension;
pub use self::dimension_trait::Dimension;
pub use self::ndindex::NdIndex;
pub use self::remove_axis::RemoveAxis;
pub use self::axes::{axes_of, Axes, AxisDescription};
pub use self::dynindeximpl::IxDynImpl;
#[macro_use] mod macros;
mod axis;
mod conversion;
pub mod dim;
mod dimension_trait;
mod dynindeximpl;
mod ndindex;
mod remove_axis;
mod axes;
#[inline(always)]
pub fn stride_offset(n: Ix, stride: Ix) -> isize {
(n as isize) * ((stride as Ixs) as isize)
}
pub fn dim_stride_overlap<D: Dimension>(dim: &D, strides: &D) -> bool {
let order = strides._fastest_varying_stride_order();
let dim = dim.slice();
let strides = strides.slice();
let mut prev_offset = 1;
for &index in order.slice() {
let d = dim[index];
let s = strides[index];
if d != 1 && (s as isize) < prev_offset {
return true;
}
prev_offset = stride_offset(d, s);
}
false
}
pub fn can_index_slice<A, D: Dimension>(data: &[A], dim: &D, strides: &D)
-> Result<(), ShapeError>
{
let len = match dim.size_checked() {
Some(l) => l,
None => return Err(from_kind(ErrorKind::OutOfBounds)),
};
for &s in strides.slice() {
let s = s as Ixs;
if s < 1 && (len != 0 || s < 0) {
return Err(from_kind(ErrorKind::Unsupported));
}
}
if len == 0 {
return Ok(());
}
let mut last_index = dim.clone();
for index in last_index.slice_mut().iter_mut() {
*index -= 1;
}
if let Some(offset) = stride_offset_checked_arithmetic(dim,
strides,
&last_index)
{
if (offset as usize) >= data.len() {
return Err(from_kind(ErrorKind::OutOfBounds));
}
if dim_stride_overlap(dim, strides) {
return Err(from_kind(ErrorKind::Unsupported));
}
} else {
return Err(from_kind(ErrorKind::OutOfBounds));
}
Ok(())
}
fn stride_offset_checked_arithmetic<D>(dim: &D, strides: &D, index: &D)
-> Option<isize>
where D: Dimension
{
let mut offset = 0;
for (&d, &i, &s) in izip!(dim.slice(), index.slice(), strides.slice()) {
if i >= d {
return None;
}
if let Some(offset_) = (i as isize)
.checked_mul((s as Ixs) as isize)
.and_then(|x| x.checked_add(offset)) {
offset = offset_;
} else {
return None;
}
}
Some(offset)
}
#[inline]
pub fn stride_offset_checked(dim: &[Ix], strides: &[Ix], index: &[Ix]) -> Option<isize> {
if index.len() != dim.len() {
return None;
}
let mut offset = 0;
for (&d, &i, &s) in izip!(dim, index, strides) {
if i >= d {
return None;
}
offset += stride_offset(i, s);
}
Some(offset)
}
pub trait DimensionExt {
#[inline]
fn axis(&self, axis: Axis) -> Ix;
#[inline]
fn set_axis(&mut self, axis: Axis, value: Ix);
}
impl<D> DimensionExt for D
where D: Dimension
{
#[inline]
fn axis(&self, axis: Axis) -> Ix {
self[axis.index()]
}
#[inline]
fn set_axis(&mut self, axis: Axis, value: Ix) {
self[axis.index()] = value;
}
}
impl<'a> DimensionExt for [Ix]
{
#[inline]
fn axis(&self, axis: Axis) -> Ix {
self[axis.index()]
}
#[inline]
fn set_axis(&mut self, axis: Axis, value: Ix) {
self[axis.index()] = value;
}
}
pub fn do_sub<A, D: Dimension>(dims: &mut D, ptr: &mut *mut A, strides: &D,
axis: usize, index: Ix) {
let dim = dims.slice()[axis];
let stride = strides.slice()[axis];
ndassert!(index < dim,
concat!("subview: Index {} must be less than axis length {} ",
"for array with shape {:?}"),
index, dim, *dims);
dims.slice_mut()[axis] = 1;
let off = stride_offset(index, stride);
unsafe {
*ptr = ptr.offset(off);
}
}
pub fn merge_axes<D>(dim: &mut D, strides: &mut D, take: Axis, into: Axis) -> bool
where D: Dimension,
{
let il = dim.axis(into);
let is = strides.axis(into) as Ixs;
let tl = dim.axis(take);
let ts = strides.axis(take) as Ixs;
if il as Ixs * is != ts {
return false;
}
dim.set_axis(into, il * tl);
dim.set_axis(take, 1);
true
}
#[cfg(test)]
mod test {
use super::IntoDimension;
use error::{from_kind, ErrorKind};
#[test]
fn slice_indexing_uncommon_strides() {
let v: Vec<_> = (0..12).collect();
let dim = (2, 3, 2).into_dimension();
let strides = (1, 2, 6).into_dimension();
assert!(super::can_index_slice(&v, &dim, &strides).is_ok());
let strides = (2, 4, 12).into_dimension();
assert_eq!(super::can_index_slice(&v, &dim, &strides),
Err(from_kind(ErrorKind::OutOfBounds)));
}
#[test]
fn overlapping_strides_dim() {
let dim = (2, 3, 2).into_dimension();
let strides = (5, 2, 1).into_dimension();
assert!(super::dim_stride_overlap(&dim, &strides));
let strides = (6, 2, 1).into_dimension();
assert!(!super::dim_stride_overlap(&dim, &strides));
let strides = (6, 0, 1).into_dimension();
assert!(super::dim_stride_overlap(&dim, &strides));
}
}