FazBrowse GitHub Viewer
|
Trending
|
URL:
|
Home
Tools:
[Download Repo ZIP]
[View Raw Code]
[Original HTTPS Page]
javascript-algorithms/src/algorithms/math/matrix/Matrix.js at master · malave/javascript-algorithms · GitHub
malave
/
javascript-algorithms
Public
forked from
trekhleb/javascript-algorithms
Notifications
You must be signed in to change notification settings
Fork
0
Star
0
Code
Pull requests
0
Actions
Projects
Security and quality
0
Insights
Additional navigation options
Code
Pull requests
Actions
Projects
Security and quality
Insights
Expand file tree
Breadcrumbs
javascript-algorithms
/
src
/
algorithms
/
math
/
matrix
/
Matrix.js
Copy path
More file actions
More file actions
Latest commit
History
History
History
309 lines (276 loc) · 7.28 KB
Breadcrumbs
javascript-algorithms
/
src
/
algorithms
/
math
/
matrix
/
Matrix.js
Copy path
File metadata and controls
309 lines (276 loc) · 7.28 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
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
/**
*
@typedef
{
number
} Cell
*
@typedef
{
Cell[][]|Cell[][][]
} Matrix
*
@typedef
{
number[]
} Shape
*
@typedef
{
number[]
} CellIndices
*/
/**
* Gets the matrix's shape.
*
*
@param
{
Matrix
} m
*
@returns
{
Shape
}
*/
export
const
shape
=
(
m
)
=>
{
const
shapes
=
[
]
;
let
dimension
=
m
;
while
(
dimension
&&
Array
.
isArray
(
dimension
)
)
{
shapes
.
push
(
dimension
.
length
)
;
dimension
=
(
dimension
.
length
&&
[
...
dimension
]
[
0
]
)
||
null
;
}
return
shapes
;
}
;
/**
* Checks if matrix has a correct type.
*
*
@param
{
Matrix
} m
*
@throws
{
Error
}
*/
const
validateType
=
(
m
)
=>
{
if
(
!
m
||
!
Array
.
isArray
(
m
)
||
!
Array
.
isArray
(
m
[
0
]
)
)
{
throw
new
Error
(
'Invalid matrix format'
)
;
}
}
;
/**
* Checks if matrix is two dimensional.
*
*
@param
{
Matrix
} m
*
@throws
{
Error
}
*/
const
validate2D
=
(
m
)
=>
{
validateType
(
m
)
;
const
aShape
=
shape
(
m
)
;
if
(
aShape
.
length
!==
2
)
{
throw
new
Error
(
'Matrix is not of 2D shape'
)
;
}
}
;
/**
* Validates that matrices are of the same shape.
*
*
@param
{
Matrix
} a
*
@param
{
Matrix
} b
*
@trows
{Error}
*/
export
const
validateSameShape
=
(
a
,
b
)
=>
{
validateType
(
a
)
;
validateType
(
b
)
;
const
aShape
=
shape
(
a
)
;
const
bShape
=
shape
(
b
)
;
if
(
aShape
.
length
!==
bShape
.
length
)
{
throw
new
Error
(
'Matrices have different dimensions'
)
;
}
while
(
aShape
.
length
&&
bShape
.
length
)
{
if
(
aShape
.
pop
(
)
!==
bShape
.
pop
(
)
)
{
throw
new
Error
(
'Matrices have different shapes'
)
;
}
}
}
;
/**
* Generates the matrix of specific shape with specific values.
*
*
@param
{
Shape
} mShape - the shape of the matrix to generate
*
@param
{
function({CellIndex}): Cell
} fill - cell values of a generated matrix.
*
@returns
{
Matrix
}
*/
export
const
generate
=
(
mShape
,
fill
)
=>
{
/**
* Generates the matrix recursively.
*
*
@param
{
Shape
} recShape - the shape of the matrix to generate
*
@param
{
CellIndices
} recIndices
*
@returns
{
Matrix
}
*/
const
generateRecursively
=
(
recShape
,
recIndices
)
=>
{
if
(
recShape
.
length
===
1
)
{
return
Array
(
recShape
[
0
]
)
.
fill
(
null
)
.
map
(
(
cellValue
,
cellIndex
)
=>
fill
(
[
...
recIndices
,
cellIndex
]
)
)
;
}
const
m
=
[
]
;
for
(
let
i
=
0
;
i
<
recShape
[
0
]
;
i
+=
1
)
{
m
.
push
(
generateRecursively
(
recShape
.
slice
(
1
)
,
[
...
recIndices
,
i
]
)
)
;
}
return
m
;
}
;
return
generateRecursively
(
mShape
,
[
]
)
;
}
;
/**
* Generates the matrix of zeros of specified shape.
*
*
@param
{
Shape
} mShape - shape of the matrix
*
@returns
{
Matrix
}
*/
export
const
zeros
=
(
mShape
)
=>
{
return
generate
(
mShape
,
(
)
=>
0
)
;
}
;
/**
*
@param
{
Matrix
} a
*
@param
{
Matrix
} b
*
@return
Matrix
*
@throws
{
Error
}
*/
export
const
dot
=
(
a
,
b
)
=>
{
// Validate inputs.
validate2D
(
a
)
;
validate2D
(
b
)
;
// Check dimensions.
const
aShape
=
shape
(
a
)
;
const
bShape
=
shape
(
b
)
;
if
(
aShape
[
1
]
!==
bShape
[
0
]
)
{
throw
new
Error
(
'Matrices have incompatible shape for multiplication'
)
;
}
// Perform matrix multiplication.
const
outputShape
=
[
aShape
[
0
]
,
bShape
[
1
]
]
;
const
c
=
zeros
(
outputShape
)
;
for
(
let
bCol
=
0
;
bCol
<
b
[
0
]
.
length
;
bCol
+=
1
)
{
for
(
let
aRow
=
0
;
aRow
<
a
.
length
;
aRow
+=
1
)
{
let
cellSum
=
0
;
for
(
let
aCol
=
0
;
aCol
<
a
[
aRow
]
.
length
;
aCol
+=
1
)
{
cellSum
+=
a
[
aRow
]
[
aCol
]
*
b
[
aCol
]
[
bCol
]
;
}
c
[
aRow
]
[
bCol
]
=
cellSum
;
}
}
return
c
;
}
;
/**
* Transposes the matrix.
*
*
@param
{
Matrix
} m
*
@returns
Matrix
*
@throws
{
Error
}
*/
export
const
t
=
(
m
)
=>
{
validate2D
(
m
)
;
const
mShape
=
shape
(
m
)
;
const
transposed
=
zeros
(
[
mShape
[
1
]
,
mShape
[
0
]
]
)
;
for
(
let
row
=
0
;
row
<
m
.
length
;
row
+=
1
)
{
for
(
let
col
=
0
;
col
<
m
[
0
]
.
length
;
col
+=
1
)
{
transposed
[
col
]
[
row
]
=
m
[
row
]
[
col
]
;
}
}
return
transposed
;
}
;
/**
* Traverses the matrix.
*
*
@param
{
Matrix
} m
*
@param
{
function(indices: CellIndices, c: Cell)
} visit
*/
export
const
walk
=
(
m
,
visit
)
=>
{
/**
* Traverses the matrix recursively.
*
*
@param
{
Matrix
} recM
*
@param
{
CellIndices
} cellIndices
*
@return
{
Matrix
}
*/
const
recWalk
=
(
recM
,
cellIndices
)
=>
{
const
recMShape
=
shape
(
recM
)
;
if
(
recMShape
.
length
===
1
)
{
for
(
let
i
=
0
;
i
<
recM
.
length
;
i
+=
1
)
{
visit
(
[
...
cellIndices
,
i
]
,
recM
[
i
]
)
;
}
}
for
(
let
i
=
0
;
i
<
recM
.
length
;
i
+=
1
)
{
recWalk
(
recM
[
i
]
,
[
...
cellIndices
,
i
]
)
;
}
}
;
recWalk
(
m
,
[
]
)
;
}
;
/**
* Gets the matrix cell value at specific index.
*
*
@param
{
Matrix
} m - Matrix that contains the cell that needs to be updated
*
@param
{
CellIndices
} cellIndices - Array of cell indices
*
@return
{
Cell
}
*/
export
const
getCellAtIndex
=
(
m
,
cellIndices
)
=>
{
// We start from the row at specific index.
let
cell
=
m
[
cellIndices
[
0
]
]
;
// Going deeper into the next dimensions but not to the last one to preserve
// the pointer to the last dimension array.
for
(
let
dimIdx
=
1
;
dimIdx
<
cellIndices
.
length
-
1
;
dimIdx
+=
1
)
{
cell
=
cell
[
cellIndices
[
dimIdx
]
]
;
}
// At this moment the cell variable points to the array at the last needed dimension.
return
cell
[
cellIndices
[
cellIndices
.
length
-
1
]
]
;
}
;
/**
* Update the matrix cell at specific index.
*
*
@param
{
Matrix
} m - Matrix that contains the cell that needs to be updated
*
@param
{
CellIndices
} cellIndices - Array of cell indices
*
@param
{
Cell
} cellValue - New cell value
*/
export
const
updateCellAtIndex
=
(
m
,
cellIndices
,
cellValue
)
=>
{
// We start from the row at specific index.
let
cell
=
m
[
cellIndices
[
0
]
]
;
// Going deeper into the next dimensions but not to the last one to preserve
// the pointer to the last dimension array.
for
(
let
dimIdx
=
1
;
dimIdx
<
cellIndices
.
length
-
1
;
dimIdx
+=
1
)
{
cell
=
cell
[
cellIndices
[
dimIdx
]
]
;
}
// At this moment the cell variable points to the array at the last needed dimension.
cell
[
cellIndices
[
cellIndices
.
length
-
1
]
]
=
cellValue
;
}
;
/**
* Adds two matrices element-wise.
*
*
@param
{
Matrix
} a
*
@param
{
Matrix
} b
*
@return
{
Matrix
}
*/
export
const
add
=
(
a
,
b
)
=>
{
validateSameShape
(
a
,
b
)
;
const
result
=
zeros
(
shape
(
a
)
)
;
walk
(
a
,
(
cellIndices
,
cellValue
)
=>
{
updateCellAtIndex
(
result
,
cellIndices
,
cellValue
)
;
}
)
;
walk
(
b
,
(
cellIndices
,
cellValue
)
=>
{
const
currentCellValue
=
getCellAtIndex
(
result
,
cellIndices
)
;
updateCellAtIndex
(
result
,
cellIndices
,
currentCellValue
+
cellValue
)
;
}
)
;
return
result
;
}
;
/**
* Multiplies two matrices element-wise.
*
*
@param
{
Matrix
} a
*
@param
{
Matrix
} b
*
@return
{
Matrix
}
*/
export
const
mul
=
(
a
,
b
)
=>
{
validateSameShape
(
a
,
b
)
;
const
result
=
zeros
(
shape
(
a
)
)
;
walk
(
a
,
(
cellIndices
,
cellValue
)
=>
{
updateCellAtIndex
(
result
,
cellIndices
,
cellValue
)
;
}
)
;
walk
(
b
,
(
cellIndices
,
cellValue
)
=>
{
const
currentCellValue
=
getCellAtIndex
(
result
,
cellIndices
)
;
updateCellAtIndex
(
result
,
cellIndices
,
currentCellValue
*
cellValue
)
;
}
)
;
return
result
;
}
;
/**
* Subtract two matrices element-wise.
*
*
@param
{
Matrix
} a
*
@param
{
Matrix
} b
*
@return
{
Matrix
}
*/
export
const
sub
=
(
a
,
b
)
=>
{
validateSameShape
(
a
,
b
)
;
const
result
=
zeros
(
shape
(
a
)
)
;
walk
(
a
,
(
cellIndices
,
cellValue
)
=>
{
updateCellAtIndex
(
result
,
cellIndices
,
cellValue
)
;
}
)
;
walk
(
b
,
(
cellIndices
,
cellValue
)
=>
{
const
currentCellValue
=
getCellAtIndex
(
result
,
cellIndices
)
;
updateCellAtIndex
(
result
,
cellIndices
,
currentCellValue
-
cellValue
)
;
}
)
;
return
result
;
}
;
Back
|
FazBrowse Home
|
New Git URL