summaryrefslogtreecommitdiff
path: root/python-fastremap.spec
blob: 8353b680e674c68996738467e234b5244ec01add (plain)
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
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
%global _empty_manifest_terminate_build 0
Name:		python-fastremap
Version:	1.13.4
Release:	1
Summary:	Remap, mask, renumber, unique, and in-place transposition of 3D labeled images. Point cloud too.
License:	LGPLv3
URL:		https://github.com/seung-lab/fastremap/
Source0:	https://mirrors.nju.edu.cn/pypi/web/packages/ad/56/8ca0eeabb68084e430e6414b0df447c10220d6f15cb2f3db2ecdaf817635/fastremap-1.13.4.tar.gz

Requires:	python3-numpy

%description
[![Build Status](https://travis-ci.org/seung-lab/fastremap.svg?branch=master)](https://travis-ci.org/seung-lab/fastremap) [![PyPI version](https://badge.fury.io/py/fastremap.svg)](https://badge.fury.io/py/fastremap)  

# fastremap

Renumber and relabel Numpy arrays at C++ speed and physically convert rectangular Numpy arrays between C and Fortran order using an in-place transposition.   

```python
import fastremap

uniq, cts = fastremap.unique(labels, return_counts=True) # may be much faster than np.unique
labels, remapping = fastremap.renumber(labels, in_place=True) # relabel values from 1 and refit data type
ptc = fastremap.point_cloud(labels) # dict of coordinates by label

labels = fastremap.refit(labels) # resize the data type of the array to fit extrema
labels = fastremap.refit(labels, value=-35) # resize the data type to fit the value provided

# remap all occurances of 1 -> 2
labels = fastremap.remap(labels, { 1: 2 }, preserve_missing_labels=True, in_place=True)

labels = fastremap.mask(labels, [1,5,13]) # set all occurances of 1,5,13 to 0
labels = fastremap.mask_except(labels, [1,5,13]) # set all labels except 1,5,13 to 0

mapping = fastremap.component_map([ 1, 2, 3, 4 ], [ 5, 5, 6, 7 ]) # { 1: 5, 2: 5, 3: 6, 4: 7 }
mapping = fastremap.inverse_component_map([ 1, 2, 1, 3 ], [ 4, 4, 5, 6 ]) # { 1: [ 4, 5 ], 2: [ 4 ], 3: [ 6 ] }

fastremap.transpose(labels) # physically transpose labels in-place
fastremap.ascontiguousarray(labels) # try to perform a physical in-place transposition to C order
fastremap.asfortranarray(labels) # try to perform a physical in-place transposition to F order

minval, maxval = fastremap.minmax(labels) # faster version of (np.min(labels), np.max(labels))

# computes number of matching adjacent pixel pairs in an image
num_pairs = fastremap.pixel_pairs(labels)  
n_foreground = fastremap.foreground(labels) # number of nonzero voxels
```

## All Available Functions 
- **unique:** Faster implementation of `np.unique`.
- **renumber:** Relabel array from 1 to N which can often use smaller datatypes.
- **remap:** Custom relabeling of values in an array from a dictionary.
- **refit:** Resize the data type of an array to the smallest that can contain the most extreme values in it.
- **mask:** Zero out labels in an array specified by a given list.
- **mask_except**: Zero out all labels except those specified in a given list.
- **component_map**: Extract an int-to-int dictionary mapping of labels from one image containing component labels to another parent labels.  
- **inverse_component_map**: Extract an int-to-list-of-ints dictionary mapping from an image containing groups of components to an image containing the components.  
- **remap_from_array:** Same as remap, but the map is an array where the key is the array index and the value is the value.
- **remap_from_array_kv:** Same as remap, but the map consists of two equal sized arrays, the first containing keys, the second containing values.
- **asfortranarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy otherwise.
- **ascontiguousarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy algorithm otherwise.
- **minmax:** Compute the min and max of an array in one pass.
- **pixel_pairs:** Computes the number of adjacent matching memory locations in an image. A quick heuristic for understanding if the image statistics are roughly similar to a connectomics segmentation.
- **foreground:** Count the number of non-zero voxels rapidly.
- **point_cloud:** Get the X,Y,Z locations of each foreground voxel grouped by label.

## `pip` Installation

```bash
pip install fastremap
```

*If not, a C++ compiler is required.*

```bash
pip install numpy
pip install fastremap --no-binary :all:
```

## Manual Installation

*A C++ compiler is required.*

```bash
sudo apt-get install g++ python3-dev 
mkvirtualenv -p python3 fastremap
pip install numpy

# Choose one:
python setup.py develop  
python setup.py install 
```

## The Problem of Remapping

Python loops are slow, so Numpy is often used to perform remapping on large arrays (hundreds of megabytes or gigabytes). In order to efficiently remap an array in Numpy you need a key-value array where the index is the key and the value is the contents of that index. 

```python 
import numpy as np 

original = np.array([ 1, 3, 5, 5, 10 ])
remap = np.array([ 0, -5, 0, 6, 0, 0, 2, 0, 0, 0, -100 ])
# Keys:            0   1  2  3  4  5  6  7  8  9    10

remapped = remap[ original ]
>>> [ -5, 6, 2, 2, -100 ]
```

If there are 32 or 64 bit labels in the array, this becomes impractical as the size of the array can grow larger than RAM. Therefore, it would be helpful to be able to perform this mapping using a C speed loop. Numba can be used for this in some circumstances. However, this library provides an alternative.

```python
import numpy as np
import fastremap 

mappings = {
  1: 100,
  2: 200,
  -3: 7,
}

arr = np.array([5, 1, 2, -5, -3, 10, 6])
# Custom remapping of -3, 5, and 6 leaving the rest alone
arr = fastremap.remap(arr, mappings, preserve_missing_labels=True) 
# result: [ 5, 100, 200, -5, 7, 10, 6 ]
```

## The Problem of Renumbering 

Sometimes a 64-bit array contains values that could be represented by an 8-bit array. However, similarly to the remapping problem, Python loops can be too slow to do this. Numpy doesn't provide a convenient way to do it either. Therefore this library provides an alternative solution.

```python
import fastremap
import numpy as np

arr = np.array([ 283732875, 439238823, 283732875, 182812404, 0 ], dtype=np.int64) 

arr, remapping = fastremap.renumber(arr, preserve_zero=True) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 0 ]
>>> remapping = { 0: 0, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False, in_place=True) # Mutate arr to use less memory
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }
```

## The Problem of In-Place Transposition 

When transitioning between different media, e.g. CPU to GPU, CPU to Network, CPU to disk, it's often necessary to physically transpose multi-dimensional arrays to reformat as C or Fortran order. Tranposing matrices is also a common action in linear algebra, but often you can get away with just changing the strides.

An out-of-place transposition is easy to write, and often faster, but it will spike peak memory consumption. This library grants the user the option of performing an in-place transposition which trades CPU time for peak memory usage. In the special case of square or cubic arrays, the in-place transpisition is both lower memory and faster.

- **fastremap.asfortranarray:** Same as np.asfortranarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.
- **fastremap.ascontiguousarray:** Same as np.ascontiguousarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.

```python
import fastremap
import numpy as np 

arr = np.ones((512,512,512), dtype=np.float32)
arr = fastremap.asfortranarray(x)

arr = np.ones((512,512,512), dtype=np.float32, order='F')
arr = fastremap.ascontiguousarray(x)
```

## C++ Usage

The in-place matrix transposition is implemented in ipt.hpp. If you're working in C++, you can also use it directly like so:

```cpp
#include "ipt.hpp"

int main() {

  int sx = 128;
  int sy = 124;
  int sz = 103;
  int sw = 3;

  auto* arr = ....;

  // All primitive number types supported
  // The array will be modified in place, 
  // so these functions are void type.
  ipt::ipt<int>(arr, sx, sy);            // 2D
  ipt::ipt<float>(arr, sx, sy, sz);      // 3D
  ipt::ipt<double>(arr, sx, sy, sz, sw); // 4D

  return 0;
}
```

--  
Made with <3



%package -n python3-fastremap
Summary:	Remap, mask, renumber, unique, and in-place transposition of 3D labeled images. Point cloud too.
Provides:	python-fastremap
BuildRequires:	python3-devel
BuildRequires:	python3-setuptools
BuildRequires:	python3-pip
BuildRequires:	python3-cffi
BuildRequires:	gcc
BuildRequires:	gdb
%description -n python3-fastremap
[![Build Status](https://travis-ci.org/seung-lab/fastremap.svg?branch=master)](https://travis-ci.org/seung-lab/fastremap) [![PyPI version](https://badge.fury.io/py/fastremap.svg)](https://badge.fury.io/py/fastremap)  

# fastremap

Renumber and relabel Numpy arrays at C++ speed and physically convert rectangular Numpy arrays between C and Fortran order using an in-place transposition.   

```python
import fastremap

uniq, cts = fastremap.unique(labels, return_counts=True) # may be much faster than np.unique
labels, remapping = fastremap.renumber(labels, in_place=True) # relabel values from 1 and refit data type
ptc = fastremap.point_cloud(labels) # dict of coordinates by label

labels = fastremap.refit(labels) # resize the data type of the array to fit extrema
labels = fastremap.refit(labels, value=-35) # resize the data type to fit the value provided

# remap all occurances of 1 -> 2
labels = fastremap.remap(labels, { 1: 2 }, preserve_missing_labels=True, in_place=True)

labels = fastremap.mask(labels, [1,5,13]) # set all occurances of 1,5,13 to 0
labels = fastremap.mask_except(labels, [1,5,13]) # set all labels except 1,5,13 to 0

mapping = fastremap.component_map([ 1, 2, 3, 4 ], [ 5, 5, 6, 7 ]) # { 1: 5, 2: 5, 3: 6, 4: 7 }
mapping = fastremap.inverse_component_map([ 1, 2, 1, 3 ], [ 4, 4, 5, 6 ]) # { 1: [ 4, 5 ], 2: [ 4 ], 3: [ 6 ] }

fastremap.transpose(labels) # physically transpose labels in-place
fastremap.ascontiguousarray(labels) # try to perform a physical in-place transposition to C order
fastremap.asfortranarray(labels) # try to perform a physical in-place transposition to F order

minval, maxval = fastremap.minmax(labels) # faster version of (np.min(labels), np.max(labels))

# computes number of matching adjacent pixel pairs in an image
num_pairs = fastremap.pixel_pairs(labels)  
n_foreground = fastremap.foreground(labels) # number of nonzero voxels
```

## All Available Functions 
- **unique:** Faster implementation of `np.unique`.
- **renumber:** Relabel array from 1 to N which can often use smaller datatypes.
- **remap:** Custom relabeling of values in an array from a dictionary.
- **refit:** Resize the data type of an array to the smallest that can contain the most extreme values in it.
- **mask:** Zero out labels in an array specified by a given list.
- **mask_except**: Zero out all labels except those specified in a given list.
- **component_map**: Extract an int-to-int dictionary mapping of labels from one image containing component labels to another parent labels.  
- **inverse_component_map**: Extract an int-to-list-of-ints dictionary mapping from an image containing groups of components to an image containing the components.  
- **remap_from_array:** Same as remap, but the map is an array where the key is the array index and the value is the value.
- **remap_from_array_kv:** Same as remap, but the map consists of two equal sized arrays, the first containing keys, the second containing values.
- **asfortranarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy otherwise.
- **ascontiguousarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy algorithm otherwise.
- **minmax:** Compute the min and max of an array in one pass.
- **pixel_pairs:** Computes the number of adjacent matching memory locations in an image. A quick heuristic for understanding if the image statistics are roughly similar to a connectomics segmentation.
- **foreground:** Count the number of non-zero voxels rapidly.
- **point_cloud:** Get the X,Y,Z locations of each foreground voxel grouped by label.

## `pip` Installation

```bash
pip install fastremap
```

*If not, a C++ compiler is required.*

```bash
pip install numpy
pip install fastremap --no-binary :all:
```

## Manual Installation

*A C++ compiler is required.*

```bash
sudo apt-get install g++ python3-dev 
mkvirtualenv -p python3 fastremap
pip install numpy

# Choose one:
python setup.py develop  
python setup.py install 
```

## The Problem of Remapping

Python loops are slow, so Numpy is often used to perform remapping on large arrays (hundreds of megabytes or gigabytes). In order to efficiently remap an array in Numpy you need a key-value array where the index is the key and the value is the contents of that index. 

```python 
import numpy as np 

original = np.array([ 1, 3, 5, 5, 10 ])
remap = np.array([ 0, -5, 0, 6, 0, 0, 2, 0, 0, 0, -100 ])
# Keys:            0   1  2  3  4  5  6  7  8  9    10

remapped = remap[ original ]
>>> [ -5, 6, 2, 2, -100 ]
```

If there are 32 or 64 bit labels in the array, this becomes impractical as the size of the array can grow larger than RAM. Therefore, it would be helpful to be able to perform this mapping using a C speed loop. Numba can be used for this in some circumstances. However, this library provides an alternative.

```python
import numpy as np
import fastremap 

mappings = {
  1: 100,
  2: 200,
  -3: 7,
}

arr = np.array([5, 1, 2, -5, -3, 10, 6])
# Custom remapping of -3, 5, and 6 leaving the rest alone
arr = fastremap.remap(arr, mappings, preserve_missing_labels=True) 
# result: [ 5, 100, 200, -5, 7, 10, 6 ]
```

## The Problem of Renumbering 

Sometimes a 64-bit array contains values that could be represented by an 8-bit array. However, similarly to the remapping problem, Python loops can be too slow to do this. Numpy doesn't provide a convenient way to do it either. Therefore this library provides an alternative solution.

```python
import fastremap
import numpy as np

arr = np.array([ 283732875, 439238823, 283732875, 182812404, 0 ], dtype=np.int64) 

arr, remapping = fastremap.renumber(arr, preserve_zero=True) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 0 ]
>>> remapping = { 0: 0, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False, in_place=True) # Mutate arr to use less memory
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }
```

## The Problem of In-Place Transposition 

When transitioning between different media, e.g. CPU to GPU, CPU to Network, CPU to disk, it's often necessary to physically transpose multi-dimensional arrays to reformat as C or Fortran order. Tranposing matrices is also a common action in linear algebra, but often you can get away with just changing the strides.

An out-of-place transposition is easy to write, and often faster, but it will spike peak memory consumption. This library grants the user the option of performing an in-place transposition which trades CPU time for peak memory usage. In the special case of square or cubic arrays, the in-place transpisition is both lower memory and faster.

- **fastremap.asfortranarray:** Same as np.asfortranarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.
- **fastremap.ascontiguousarray:** Same as np.ascontiguousarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.

```python
import fastremap
import numpy as np 

arr = np.ones((512,512,512), dtype=np.float32)
arr = fastremap.asfortranarray(x)

arr = np.ones((512,512,512), dtype=np.float32, order='F')
arr = fastremap.ascontiguousarray(x)
```

## C++ Usage

The in-place matrix transposition is implemented in ipt.hpp. If you're working in C++, you can also use it directly like so:

```cpp
#include "ipt.hpp"

int main() {

  int sx = 128;
  int sy = 124;
  int sz = 103;
  int sw = 3;

  auto* arr = ....;

  // All primitive number types supported
  // The array will be modified in place, 
  // so these functions are void type.
  ipt::ipt<int>(arr, sx, sy);            // 2D
  ipt::ipt<float>(arr, sx, sy, sz);      // 3D
  ipt::ipt<double>(arr, sx, sy, sz, sw); // 4D

  return 0;
}
```

--  
Made with <3



%package help
Summary:	Development documents and examples for fastremap
Provides:	python3-fastremap-doc
%description help
[![Build Status](https://travis-ci.org/seung-lab/fastremap.svg?branch=master)](https://travis-ci.org/seung-lab/fastremap) [![PyPI version](https://badge.fury.io/py/fastremap.svg)](https://badge.fury.io/py/fastremap)  

# fastremap

Renumber and relabel Numpy arrays at C++ speed and physically convert rectangular Numpy arrays between C and Fortran order using an in-place transposition.   

```python
import fastremap

uniq, cts = fastremap.unique(labels, return_counts=True) # may be much faster than np.unique
labels, remapping = fastremap.renumber(labels, in_place=True) # relabel values from 1 and refit data type
ptc = fastremap.point_cloud(labels) # dict of coordinates by label

labels = fastremap.refit(labels) # resize the data type of the array to fit extrema
labels = fastremap.refit(labels, value=-35) # resize the data type to fit the value provided

# remap all occurances of 1 -> 2
labels = fastremap.remap(labels, { 1: 2 }, preserve_missing_labels=True, in_place=True)

labels = fastremap.mask(labels, [1,5,13]) # set all occurances of 1,5,13 to 0
labels = fastremap.mask_except(labels, [1,5,13]) # set all labels except 1,5,13 to 0

mapping = fastremap.component_map([ 1, 2, 3, 4 ], [ 5, 5, 6, 7 ]) # { 1: 5, 2: 5, 3: 6, 4: 7 }
mapping = fastremap.inverse_component_map([ 1, 2, 1, 3 ], [ 4, 4, 5, 6 ]) # { 1: [ 4, 5 ], 2: [ 4 ], 3: [ 6 ] }

fastremap.transpose(labels) # physically transpose labels in-place
fastremap.ascontiguousarray(labels) # try to perform a physical in-place transposition to C order
fastremap.asfortranarray(labels) # try to perform a physical in-place transposition to F order

minval, maxval = fastremap.minmax(labels) # faster version of (np.min(labels), np.max(labels))

# computes number of matching adjacent pixel pairs in an image
num_pairs = fastremap.pixel_pairs(labels)  
n_foreground = fastremap.foreground(labels) # number of nonzero voxels
```

## All Available Functions 
- **unique:** Faster implementation of `np.unique`.
- **renumber:** Relabel array from 1 to N which can often use smaller datatypes.
- **remap:** Custom relabeling of values in an array from a dictionary.
- **refit:** Resize the data type of an array to the smallest that can contain the most extreme values in it.
- **mask:** Zero out labels in an array specified by a given list.
- **mask_except**: Zero out all labels except those specified in a given list.
- **component_map**: Extract an int-to-int dictionary mapping of labels from one image containing component labels to another parent labels.  
- **inverse_component_map**: Extract an int-to-list-of-ints dictionary mapping from an image containing groups of components to an image containing the components.  
- **remap_from_array:** Same as remap, but the map is an array where the key is the array index and the value is the value.
- **remap_from_array_kv:** Same as remap, but the map consists of two equal sized arrays, the first containing keys, the second containing values.
- **asfortranarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy otherwise.
- **ascontiguousarray:** Perform an in-place matrix transposition for rectangular arrays if memory is contiguous, standard numpy algorithm otherwise.
- **minmax:** Compute the min and max of an array in one pass.
- **pixel_pairs:** Computes the number of adjacent matching memory locations in an image. A quick heuristic for understanding if the image statistics are roughly similar to a connectomics segmentation.
- **foreground:** Count the number of non-zero voxels rapidly.
- **point_cloud:** Get the X,Y,Z locations of each foreground voxel grouped by label.

## `pip` Installation

```bash
pip install fastremap
```

*If not, a C++ compiler is required.*

```bash
pip install numpy
pip install fastremap --no-binary :all:
```

## Manual Installation

*A C++ compiler is required.*

```bash
sudo apt-get install g++ python3-dev 
mkvirtualenv -p python3 fastremap
pip install numpy

# Choose one:
python setup.py develop  
python setup.py install 
```

## The Problem of Remapping

Python loops are slow, so Numpy is often used to perform remapping on large arrays (hundreds of megabytes or gigabytes). In order to efficiently remap an array in Numpy you need a key-value array where the index is the key and the value is the contents of that index. 

```python 
import numpy as np 

original = np.array([ 1, 3, 5, 5, 10 ])
remap = np.array([ 0, -5, 0, 6, 0, 0, 2, 0, 0, 0, -100 ])
# Keys:            0   1  2  3  4  5  6  7  8  9    10

remapped = remap[ original ]
>>> [ -5, 6, 2, 2, -100 ]
```

If there are 32 or 64 bit labels in the array, this becomes impractical as the size of the array can grow larger than RAM. Therefore, it would be helpful to be able to perform this mapping using a C speed loop. Numba can be used for this in some circumstances. However, this library provides an alternative.

```python
import numpy as np
import fastremap 

mappings = {
  1: 100,
  2: 200,
  -3: 7,
}

arr = np.array([5, 1, 2, -5, -3, 10, 6])
# Custom remapping of -3, 5, and 6 leaving the rest alone
arr = fastremap.remap(arr, mappings, preserve_missing_labels=True) 
# result: [ 5, 100, 200, -5, 7, 10, 6 ]
```

## The Problem of Renumbering 

Sometimes a 64-bit array contains values that could be represented by an 8-bit array. However, similarly to the remapping problem, Python loops can be too slow to do this. Numpy doesn't provide a convenient way to do it either. Therefore this library provides an alternative solution.

```python
import fastremap
import numpy as np

arr = np.array([ 283732875, 439238823, 283732875, 182812404, 0 ], dtype=np.int64) 

arr, remapping = fastremap.renumber(arr, preserve_zero=True) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 0 ]
>>> remapping = { 0: 0, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False) # Returns uint8 array
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }

arr, remapping = fastremap.renumber(arr, preserve_zero=False, in_place=True) # Mutate arr to use less memory
>>> arr = [ 1, 2, 1, 3, 4 ]
>>> remapping = { 0: 4, 283732875: 1, 439238823: 2, 182812404: 3 }
```

## The Problem of In-Place Transposition 

When transitioning between different media, e.g. CPU to GPU, CPU to Network, CPU to disk, it's often necessary to physically transpose multi-dimensional arrays to reformat as C or Fortran order. Tranposing matrices is also a common action in linear algebra, but often you can get away with just changing the strides.

An out-of-place transposition is easy to write, and often faster, but it will spike peak memory consumption. This library grants the user the option of performing an in-place transposition which trades CPU time for peak memory usage. In the special case of square or cubic arrays, the in-place transpisition is both lower memory and faster.

- **fastremap.asfortranarray:** Same as np.asfortranarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.
- **fastremap.ascontiguousarray:** Same as np.ascontiguousarray but will perform the transposition in-place for 1, 2, 3, and 4D arrays. 2D and 3D square matrices are faster to process than with Numpy.

```python
import fastremap
import numpy as np 

arr = np.ones((512,512,512), dtype=np.float32)
arr = fastremap.asfortranarray(x)

arr = np.ones((512,512,512), dtype=np.float32, order='F')
arr = fastremap.ascontiguousarray(x)
```

## C++ Usage

The in-place matrix transposition is implemented in ipt.hpp. If you're working in C++, you can also use it directly like so:

```cpp
#include "ipt.hpp"

int main() {

  int sx = 128;
  int sy = 124;
  int sz = 103;
  int sw = 3;

  auto* arr = ....;

  // All primitive number types supported
  // The array will be modified in place, 
  // so these functions are void type.
  ipt::ipt<int>(arr, sx, sy);            // 2D
  ipt::ipt<float>(arr, sx, sy, sz);      // 3D
  ipt::ipt<double>(arr, sx, sy, sz, sw); // 4D

  return 0;
}
```

--  
Made with <3



%prep
%autosetup -n fastremap-1.13.4

%build
%py3_build

%install
%py3_install
install -d -m755 %{buildroot}/%{_pkgdocdir}
if [ -d doc ]; then cp -arf doc %{buildroot}/%{_pkgdocdir}; fi
if [ -d docs ]; then cp -arf docs %{buildroot}/%{_pkgdocdir}; fi
if [ -d example ]; then cp -arf example %{buildroot}/%{_pkgdocdir}; fi
if [ -d examples ]; then cp -arf examples %{buildroot}/%{_pkgdocdir}; fi
pushd %{buildroot}
if [ -d usr/lib ]; then
	find usr/lib -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/lib64 ]; then
	find usr/lib64 -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/bin ]; then
	find usr/bin -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/sbin ]; then
	find usr/sbin -type f -printf "/%h/%f\n" >> filelist.lst
fi
touch doclist.lst
if [ -d usr/share/man ]; then
	find usr/share/man -type f -printf "/%h/%f.gz\n" >> doclist.lst
fi
popd
mv %{buildroot}/filelist.lst .
mv %{buildroot}/doclist.lst .

%files -n python3-fastremap -f filelist.lst
%dir %{python3_sitearch}/*

%files help -f doclist.lst
%{_docdir}/*

%changelog
* Tue Apr 25 2023 Python_Bot <Python_Bot@openeuler.org> - 1.13.4-1
- Package Spec generated