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import
{
isInteger
}
from
'./number.js'
import
{
isNumber
,
isBigNumber
,
isArray
,
isString
}
from
'./is.js'
import
{
format
}
from
'./string.js'
import
{
DimensionError
}
from
'../error/DimensionError.js'
import
{
IndexError
}
from
'../error/IndexError.js'
import
{
deepStrictEqual
}
from
'./object.js'
/**
* Calculate the size of a multi dimensional array.
* This function checks the size of the first entry, it does not validate
* whether all dimensions match. (use function `validate` for that)
*
@param
{
Array
} x
*
@Return
{Number[]} size
*/
export
function
arraySize
(
x
)
{
const
s
=
[
]
while
(
Array
.
isArray
(
x
)
)
{
s
.
push
(
x
.
length
)
x
=
x
[
0
]
}
return
s
}
/**
* Recursively validate whether each element in a multi dimensional array
* has a size corresponding to the provided size array.
*
@param
{
Array
} array Array to be validated
*
@param
{
number[]
} size Array with the size of each dimension
*
@param
{
number
} dim Current dimension
*
@throws
DimensionError
*
@private
*/
function
_validate
(
array
,
size
,
dim
)
{
let
i
const
len
=
array
.
length
if
(
len
!==
size
[
dim
]
)
{
throw
new
DimensionError
(
len
,
size
[
dim
]
)
}
if
(
dim
<
size
.
length
-
1
)
{
// recursively validate each child array
const
dimNext
=
dim
+
1
for
(
i
=
0
;
i
<
len
;
i
++
)
{
const
child
=
array
[
i
]
if
(
!
Array
.
isArray
(
child
)
)
{
throw
new
DimensionError
(
size
.
length
-
1
,
size
.
length
,
'<'
)
}
_validate
(
array
[
i
]
,
size
,
dimNext
)
}
}
else
{
// last dimension. none of the childs may be an array
for
(
i
=
0
;
i
<
len
;
i
++
)
{
if
(
Array
.
isArray
(
array
[
i
]
)
)
{
throw
new
DimensionError
(
size
.
length
+
1
,
size
.
length
,
'>'
)
}
}
}
}
/**
* Validate whether each element in a multi dimensional array has
* a size corresponding to the provided size array.
*
@param
{
Array
} array Array to be validated
*
@param
{
number[]
} size Array with the size of each dimension
*
@throws
DimensionError
*/
export
function
validate
(
array
,
size
)
{
const
isScalar
=
(
size
.
length
===
0
)
if
(
isScalar
)
{
// scalar
if
(
Array
.
isArray
(
array
)
)
{
throw
new
DimensionError
(
array
.
length
,
0
)
}
}
else
{
// array
_validate
(
array
,
size
,
0
)
}
}
/**
* Validate whether the source of the index matches the size of the Array
*
@param
{
Array | Matrix
} array Array to be validated
*
@param
{
Index
} index Index with the source information to validate
*
@throws
DimensionError
*/
export
function
validateIndexSourceSize
(
value
,
index
)
{
const
valueSize
=
value
.
isMatrix
?
value
.
_size
:
arraySize
(
value
)
const
sourceSize
=
index
.
_sourceSize
// checks if the source size is not null and matches the valueSize
sourceSize
.
forEach
(
(
sourceDim
,
i
)
=>
{
if
(
sourceDim
!==
null
&&
sourceDim
!==
valueSize
[
i
]
)
{
throw
new
DimensionError
(
sourceDim
,
valueSize
[
i
]
)
}
}
)
}
/**
* Test whether index is an integer number with index >= 0 and index < length
* when length is provided
*
@param
{
number
} index Zero-based index
*
@param
{
number
} [length] Length of the array
*/
export
function
validateIndex
(
index
,
length
)
{
if
(
index
!==
undefined
)
{
if
(
!
isNumber
(
index
)
||
!
isInteger
(
index
)
)
{
throw
new
TypeError
(
'Index must be an integer (value: '
+
index
+
')'
)
}
if
(
index
<
0
||
(
typeof
length
===
'number'
&&
index
>=
length
)
)
{
throw
new
IndexError
(
index
,
length
)
}
}
}
/**
* Test if and index has empty values
*
@param
{
number
} index Zero-based index
*/
export
function
isEmptyIndex
(
index
)
{
for
(
let
i
=
0
;
i
<
index
.
_dimensions
.
length
;
++
i
)
{
const
dimension
=
index
.
_dimensions
[
i
]
if
(
dimension
.
_data
&&
isArray
(
dimension
.
_data
)
)
{
if
(
dimension
.
_size
[
0
]
===
0
)
{
return
true
}
}
else
if
(
dimension
.
isRange
)
{
if
(
dimension
.
start
===
dimension
.
end
)
{
return
true
}
}
else
if
(
isString
(
dimension
)
)
{
if
(
dimension
.
length
===
0
)
{
return
true
}
}
}
return
false
}
/**
* Resize a multi dimensional array. The resized array is returned.
*
@param
{
Array | number
} array Array to be resized
*
@param
{
number[]
} size Array with the size of each dimension
*
@param
{
*
} [defaultValue=0] Value to be filled in in new entries,
* zero by default. Specify for example `null`,
* to clearly see entries that are not explicitly
* set.
*
@return
{
Array
} array The resized array
*/
export
function
resize
(
array
,
size
,
defaultValue
)
{
// check the type of the arguments
if
(
!
Array
.
isArray
(
size
)
)
{
throw
new
TypeError
(
'Array expected'
)
}
if
(
size
.
length
===
0
)
{
throw
new
Error
(
'Resizing to scalar is not supported'
)
}
// check whether size contains positive integers
size
.
forEach
(
function
(
value
)
{
if
(
!
isNumber
(
value
)
||
!
isInteger
(
value
)
||
value
<
0
)
{
throw
new
TypeError
(
'Invalid size, must contain positive integers '
+
'(size: '
+
format
(
size
)
+
')'
)
}
}
)
// convert number to an array
if
(
isNumber
(
array
)
||
isBigNumber
(
array
)
)
{
array
=
[
array
]
}
// recursively resize the array
const
_defaultValue
=
(
defaultValue
!==
undefined
)
?
defaultValue
:
0
_resize
(
array
,
size
,
0
,
_defaultValue
)
return
array
}
/**
* Recursively resize a multi dimensional array
*
@param
{
Array
} array Array to be resized
*
@param
{
number[]
} size Array with the size of each dimension
*
@param
{
number
} dim Current dimension
*
@param
{
*
} [defaultValue] Value to be filled in in new entries,
* undefined by default.
*
@private
*/
function
_resize
(
array
,
size
,
dim
,
defaultValue
)
{
let
i
let
elem
const
oldLen
=
array
.
length
const
newLen
=
size
[
dim
]
const
minLen
=
Math
.
min
(
oldLen
,
newLen
)
// apply new length
array
.
length
=
newLen
if
(
dim
<
size
.
length
-
1
)
{
// non-last dimension
const
dimNext
=
dim
+
1
// resize existing child arrays
for
(
i
=
0
;
i
<
minLen
;
i
++
)
{
// resize child array
elem
=
array
[
i
]
if
(
!
Array
.
isArray
(
elem
)
)
{
elem
=
[
elem
]
// add a dimension
array
[
i
]
=
elem
}
_resize
(
elem
,
size
,
dimNext
,
defaultValue
)
}
// create new child arrays
for
(
i
=
minLen
;
i
<
newLen
;
i
++
)
{
// get child array
elem
=
[
]
array
[
i
]
=
elem
// resize new child array
_resize
(
elem
,
size
,
dimNext
,
defaultValue
)
}
}
else
{
// last dimension
// remove dimensions of existing values
for
(
i
=
0
;
i
<
minLen
;
i
++
)
{
while
(
Array
.
isArray
(
array
[
i
]
)
)
{
array
[
i
]
=
array
[
i
]
[
0
]
}
}
// fill new elements with the default value
for
(
i
=
minLen
;
i
<
newLen
;
i
++
)
{
array
[
i
]
=
defaultValue
}
}
}
/**
* Re-shape a multi dimensional array to fit the specified dimensions
*
@param
{
Array
} array Array to be reshaped
*
@param
{
number[]
} sizes List of sizes for each dimension
*
@returns
{
Array
} Array whose data has been formatted to fit the
* specified dimensions
*
*
@throws
{
DimensionError
} If the product of the new dimension sizes does
* not equal that of the old ones
*/
export
function
reshape
(
array
,
sizes
)
{
const
flatArray
=
flatten
(
array
)
const
currentLength
=
flatArray
.
length
if
(
!
Array
.
isArray
(
array
)
||
!
Array
.
isArray
(
sizes
)
)
{
throw
new
TypeError
(
'Array expected'
)
}
if
(
sizes
.
length
===
0
)
{
throw
new
DimensionError
(
0
,
currentLength
,
'!='
)
}
sizes
=
processSizesWildcard
(
sizes
,
currentLength
)
const
newLength
=
product
(
sizes
)
if
(
currentLength
!==
newLength
)
{
throw
new
DimensionError
(
newLength
,
currentLength
,
'!='
)
}
try
{
return
_reshape
(
flatArray
,
sizes
)
}
catch
(
e
)
{
if
(
e
instanceof
DimensionError
)
{
throw
new
DimensionError
(
newLength
,
currentLength
,
'!='
)
}
throw
e
}
}
/**
* Replaces the wildcard -1 in the sizes array.
*
@param
{
number[]
} sizes List of sizes for each dimension. At most on wildcard.
*
@param
{
number
} currentLength Number of elements in the array.
*
@throws
{
Error
} If more than one wildcard or unable to replace it.
*
@returns
{
number[]
} The sizes array with wildcard replaced.
*/
export
function
processSizesWildcard
(
sizes
,
currentLength
)
{
const
newLength
=
product
(
sizes
)
const
processedSizes
=
sizes
.
slice
(
)
const
WILDCARD
=
-
1
const
wildCardIndex
=
sizes
.
indexOf
(
WILDCARD
)
const
isMoreThanOneWildcard
=
sizes
.
indexOf
(
WILDCARD
,
wildCardIndex
+
1
)
>=
0
if
(
isMoreThanOneWildcard
)
{
throw
new
Error
(
'More than one wildcard in sizes'
)
}
const
hasWildcard
=
wildCardIndex
>=
0
const
canReplaceWildcard
=
currentLength
%
newLength
===
0
if
(
hasWildcard
)
{
if
(
canReplaceWildcard
)
{
processedSizes
[
wildCardIndex
]
=
-
currentLength
/
newLength
}
else
{
throw
new
Error
(
'Could not replace wildcard, since '
+
currentLength
+
' is no multiple of '
+
(
-
newLength
)
)
}
}
return
processedSizes
}
/**
* Computes the product of all array elements.
*
@param
{
number[]
} array Array of factors
*
@returns
{
number
} Product of all elements
*/
function
product
(
array
)
{
return
array
.
reduce
(
(
prev
,
curr
)
=>
prev
*
curr
,
1
)
}
/**
* Iteratively re-shape a multi dimensional array to fit the specified dimensions
*
@param
{
Array
} array Array to be reshaped
*
@param
{
number[]
} sizes List of sizes for each dimension
*
@returns
{
Array
} Array whose data has been formatted to fit the
* specified dimensions
*/
function
_reshape
(
array
,
sizes
)
{
// testing if there are enough elements for the requested shape
let
tmpArray
=
array
let
tmpArray2
// for each dimensions starting by the last one and ignoring the first one
for
(
let
sizeIndex
=
sizes
.
length
-
1
;
sizeIndex
>
0
;
sizeIndex
--
)
{
const
size
=
sizes
[
sizeIndex
]
tmpArray2
=
[
]
// aggregate the elements of the current tmpArray in elements of the requested size
const
length
=
tmpArray
.
length
/
size
for
(
let
i
=
0
;
i
<
length
;
i
++
)
{
tmpArray2
.
push
(
tmpArray
.
slice
(
i
*
size
,
(
i
+
1
)
*
size
)
)
}
// set it as the new tmpArray for the next loop turn or for return
tmpArray
=
tmpArray2
}
return
tmpArray
}
/**
* Squeeze a multi dimensional array
*
@param
{
Array
} array
*
@param
{
Array
} [size]
*
@returns
{
Array
} returns the array itself
*/
export
function
squeeze
(
array
,
size
)
{
const
s
=
size
||
arraySize
(
array
)
// squeeze outer dimensions
while
(
Array
.
isArray
(
array
)
&&
array
.
length
===
1
)
{
array
=
array
[
0
]
s
.
shift
(
)
}
// find the first dimension to be squeezed
let
dims
=
s
.
length
while
(
s
[
dims
-
1
]
===
1
)
{
dims
--
}
// squeeze inner dimensions
if
(
dims
<
s
.
length
)
{
array
=
_squeeze
(
array
,
dims
,
0
)
s
.
length
=
dims
}
return
array
}
/**
* Recursively squeeze a multi dimensional array
*
@param
{
Array
} array
*
@param
{
number
} dims Required number of dimensions
*
@param
{
number
} dim Current dimension
*
@returns
{
Array | *
} Returns the squeezed array
*
@private
*/
function
_squeeze
(
array
,
dims
,
dim
)
{
let
i
,
ii
if
(
dim
<
dims
)
{
const
next
=
dim
+
1
for
(
i
=
0
,
ii
=
array
.
length
;
i
<
ii
;
i
++
)
{
array
[
i
]
=
_squeeze
(
array
[
i
]
,
dims
,
next
)
}
}
else
{
while
(
Array
.
isArray
(
array
)
)
{
array
=
array
[
0
]
}
}
return
array
}
/**
* Unsqueeze a multi dimensional array: add dimensions when missing
*
* Paramter `size` will be mutated to match the new, unqueezed matrix size.
*
*
@param
{
Array
} array
*
@param
{
number
} dims Desired number of dimensions of the array
*
@param
{
number
} [outer] Number of outer dimensions to be added
*
@param
{
Array
} [size] Current size of array.
*
@returns
{
Array
} returns the array itself
*
@private
*/
export
function
unsqueeze
(
array
,
dims
,
outer
,
size
)
{
const
s
=
size
||
arraySize
(
array
)
// unsqueeze outer dimensions
if
(
outer
)
{
for
(
let
i
=
0
;
i
<
outer
;
i
++
)
{
array
=
[
array
]
s
.
unshift
(
1
)
}
}
// unsqueeze inner dimensions
array
=
_unsqueeze
(
array
,
dims
,
0
)
while
(
s
.
length
<
dims
)
{
s
.
push
(
1
)
}
return
array
}
/**
* Recursively unsqueeze a multi dimensional array
*
@param
{
Array
} array
*
@param
{
number
} dims Required number of dimensions
*
@param
{
number
} dim Current dimension
*
@returns
{
Array | *
} Returns the squeezed array
*
@private
*/
function
_unsqueeze
(
array
,
dims
,
dim
)
{
let
i
,
ii
if
(
Array
.
isArray
(
array
)
)
{
const
next
=
dim
+
1
for
(
i
=
0
,
ii
=
array
.
length
;
i
<
ii
;
i
++
)
{
array
[
i
]
=
_unsqueeze
(
array
[
i
]
,
dims
,
next
)
}
}
else
{
for
(
let
d
=
dim
;
d
<
dims
;
d
++
)
{
array
=
[
array
]
}
}
return
array
}
/**
* Flatten a multi dimensional array, put all elements in a one dimensional
* array
*
@param
{
Array
} array A multi dimensional array
*
@return
{
Array
} The flattened array (1 dimensional)
*/
export
function
flatten
(
array
)
{
if
(
!
Array
.
isArray
(
array
)
)
{
// if not an array, return as is
return
array
}
const
flat
=
[
]
array
.
forEach
(
function
callback
(
value
)
{
if
(
Array
.
isArray
(
value
)
)
{
value
.
forEach
(
callback
)
// traverse through sub-arrays recursively
}
else
{
flat
.
push
(
value
)
}
}
)
return
flat
}
/**
* A safe map
*
@param
{
Array
} array
*
@param
{
function
} callback
*/
export
function
map
(
array
,
callback
)
{
return
Array
.
prototype
.
map
.
call
(
array
,
callback
)
}
/**
* A safe forEach
*
@param
{
Array
} array
*
@param
{
function
} callback
*/
export
function
forEach
(
array
,
callback
)
{
Array
.
prototype
.
forEach
.
call
(
array
,
callback
)
}
/**
* A safe filter
*
@param
{
Array
} array
*
@param
{
function
} callback
*/
export
function
filter
(
array
,
callback
)
{
if
(
arraySize
(
array
)
.
length
!==
1
)
{
throw
new
Error
(
'Only one dimensional matrices supported'
)
}
return
Array
.
prototype
.
filter
.
call
(
array
,
callback
)
}
/**
* Filter values in a callback given a regular expression
*
@param
{
Array
} array
*
@param
{
RegExp
} regexp
*
@return
{
Array
} Returns the filtered array
*
@private
*/
export
function
filterRegExp
(
array
,
regexp
)
{
if
(
arraySize
(
array
)
.
length
!==
1
)
{
throw
new
Error
(
'Only one dimensional matrices supported'
)
}
return
Array
.
prototype
.
filter
.
call
(
array
,
(
entry
)
=>
regexp
.
test
(
entry
)
)
}
/**
* A safe join
*
@param
{
Array
} array
*
@param
{
string
} separator
*/
export
function
join
(
array
,
separator
)
{
return
Array
.
prototype
.
join
.
call
(
array
,
separator
)
}
/**
* Assign a numeric identifier to every element of a sorted array
*
@param
{
Array
} a An array
*
@return
{
Array
} An array of objects containing the original value and its identifier
*/
export
function
identify
(
a
)
{
if
(
!
Array
.
isArray
(
a
)
)
{
throw
new
TypeError
(
'Array input expected'
)
}
if
(
a
.
length
===
0
)
{
return
a
}
const
b
=
[
]
let
count
=
0
b
[
0
]
=
{
value
:
a
[
0
]
,
identifier
:
0
}
for
(
let
i
=
1
;
i
<
a
.
length
;
i
++
)
{
if
(
a
[
i
]
===
a
[
i
-
1
]
)
{
count
++
}
else
{
count
=
0
}
b
.
push
(
{
value
:
a
[
i
]
,
identifier
:
count
}
)
}
return
b
}
/**
* Remove the numeric identifier from the elements
*
@param
{
array
} a An array
*
@return
{
array
} An array of values without identifiers
*/
export
function
generalize
(
a
)
{
if
(
!
Array
.
isArray
(
a
)
)
{
throw
new
TypeError
(
'Array input expected'
)
}
if
(
a
.
length
===
0
)
{
return
a
}
const
b
=
[
]
for
(
let
i
=
0
;
i
<
a
.
length
;
i
++
)
{
b
.
push
(
a
[
i
]
.
value
)
}
return
b
}
/**
* Check the datatype of a given object
* This is a low level implementation that should only be used by
* parent Matrix classes such as SparseMatrix or DenseMatrix
* This method does not validate Array Matrix shape
*
@param
{
Array
} array
*
@param
{
function
} typeOf Callback function to use to determine the type of a value
*
@return
{
string
}
*/
export
function
getArrayDataType
(
array
,
typeOf
)
{
let
type
// to hold type info
let
length
=
0
// to hold length value to ensure it has consistent sizes
for
(
let
i
=
0
;
i
<
array
.
length
;
i
++
)
{
const
item
=
array
[
i
]
const
isArray
=
Array
.
isArray
(
item
)
// Saving the target matrix row size
if
(
i
===
0
&&
isArray
)
{
length
=
item
.
length
}
// If the current item is an array but the length does not equal the targetVectorSize
if
(
isArray
&&
item
.
length
!==
length
)
{
return
undefined
}
const
itemType
=
isArray
?
getArrayDataType
(
item
,
typeOf
)
// recurse into a nested array
:
typeOf
(
item
)
if
(
type
===
undefined
)
{
type
=
itemType
// first item
}
else
if
(
type
!==
itemType
)
{
return
'mixed'
}
else
{
// we're good, everything has the same type so far
}
}
return
type
}
/**
* Return the last item from an array
*
@param
{
array
}
*
@returns
{
*
}
*/
export
function
last
(
array
)
{
return
array
[
array
.
length
-
1
]
}
/**
* Get all but the last element of array.
*
@param
{
array
}
*
@returns
{
*
}
*/
export
function
initial
(
array
)
{
return
array
.
slice
(
0
,
array
.
length
-
1
)
}
/**
* Test whether an array or string contains an item
*
@param
{
Array | string
} array
*
@param
{
*
} item
*
@return
{
boolean
}
*/
export
function
contains
(
array
,
item
)
{
return
array
.
indexOf
(
item
)
!==
-
1
}
/**
* Recursively concatenate two matrices.
* The contents of the matrices is not cloned.
*
@param
{
Array
} a Multi dimensional array
*
@param
{
Array
} b Multi dimensional array
*
@param
{
number
} concatDim The dimension on which to concatenate (zero-based)
*
@param
{
number
} dim The current dim (zero-based)
*
@return
{
Array
} c The concatenated matrix
*
@private
*/
function
concatRecursive
(
a
,
b
,
concatDim
,
dim
)
{
if
(
dim
<
concatDim
)
{
// recurse into next dimension
if
(
a
.
length
!==
b
.
length
)
{
throw
new
DimensionError
(
a
.
length
,
b
.
length
)
}
const
c
=
[
]
for
(
let
i
=
0
;
i
<
a
.
length
;
i
++
)
{
c
[
i
]
=
concatRecursive
(
a
[
i
]
,
b
[
i
]
,
concatDim
,
dim
+
1
)
}
return
c
}
else
{
// concatenate this dimension
return
a
.
concat
(
b
)
}
}
/**
* Concatenates many arrays in the specified direction
*
@param
{
...Array
} arrays All the arrays to concatenate
*
@param
{
number
} concatDim The dimension on which to concatenate (zero-based)
*
@returns
*/
export
function
concat
(
)
{
const
arrays
=
Array
.
prototype
.
slice
.
call
(
arguments
,
0
,
-
1
)
const
concatDim
=
Array
.
prototype
.
slice
.
call
(
arguments
,
-
1
)
if
(
arrays
.
length
===
1
)
{
return
arrays
[
0
]
}
if
(
arrays
.
length
>
1
)
{
return
arrays
.
slice
(
1
)
.
reduce
(
function
(
A
,
B
)
{
return
concatRecursive
(
A
,
B
,
concatDim
,
0
)
}
,
arrays
[
0
]
)
}
else
{
throw
new
Error
(
'Wrong number of arguments in function concat'
)
}
}
/**
* Receives two or more sizes and get's the broadcasted size for both.
*
@param
{
...number[]
} sizes Sizes to broadcast together
*
@returns
*/
export
function
broadcastSizes
(
...
sizes
)
{
const
dimensions
=
sizes
.
map
(
(
s
)
=>
s
.
length
)
const
N
=
Math
.
max
(
...
dimensions
)
const
sizeMax
=
new
Array
(
N
)
.
fill
(
null
)
// check for every size
for
(
let
i
=
0
;
i
<
sizes
.
length
;
i
++
)
{
const
size
=
sizes
[
i
]
const
dim
=
dimensions
[
i
]
for
(
let
j
=
0
;
j
<
dim
;
j
++
)
{
const
n
=
N
-
dim
+
j
if
(
size
[
j
]
>
sizeMax
[
n
]
)
{
sizeMax
[
n
]
=
size
[
j
]
}
}
}
for
(
let
i
=
0
;
i
<
sizes
.
length
;
i
++
)
{
checkBroadcastingRules
(
sizes
[
i
]
,
sizeMax
)
}
return
sizeMax
}
/**
* Checks if it's possible to broadcast a size to another size
*
@param
{
number[]
} size The size of the array to check
*
@param
{
number[]
} toSize The size of the array to validate if it can be broadcasted to
*/
export
function
checkBroadcastingRules
(
size
,
toSize
)
{
const
N
=
toSize
.
length
const
dim
=
size
.
length
for
(
let
j
=
0
;
j
<
dim
;
j
++
)
{
const
n
=
N
-
dim
+
j
if
(
(
size
[
j
]
<
toSize
[
n
]
&&
size
[
j
]
>
1
)
||
(
size
[
j
]
>
toSize
[
n
]
)
)
{
throw
new
Error
(
`shape missmatch: missmatch is found in arg with shape (
${
size
}
) not possible to broadcast dimension
${
dim
}
with size
${
size
[
j
]
}
to size
${
toSize
[
n
]
}
`
)
}
}
}
/**
* Broadcasts a single array to a certain size
*
@param
{
array
} array Array to be broadcasted
*
@param
{
number[]
} toSize Size to broadcast the array
*
@returns
The broadcasted array
*/
export
function
broadcastTo
(
array
,
toSize
)
{
let
Asize
=
arraySize
(
array
)
if
(
deepStrictEqual
(
Asize
,
toSize
)
)
{
return
array
}
checkBroadcastingRules
(
Asize
,
toSize
)
const
broadcastedSize
=
broadcastSizes
(
Asize
,
toSize
)
const
N
=
broadcastedSize
.
length
const
paddedSize
=
[
...
Array
(
N
-
Asize
.
length
)
.
fill
(
1
)
,
...
Asize
]
let
A
=
clone
(
array
)
// reshape A if needed to make it ready for concat
if
(
Asize
.
length
<
N
)
{
A
=
reshape
(
A
,
paddedSize
)
Asize
=
arraySize
(
A
)
}
// stretches the array on each dimension to make it the same size as index
for
(
let
dim
=
0
;
dim
<
N
;
dim
++
)
{
if
(
Asize
[
dim
]
<
broadcastedSize
[
dim
]
)
{
A
=
stretch
(
A
,
broadcastedSize
[
dim
]
,
dim
)
Asize
=
arraySize
(
A
)
}
}
return
A
}
/**
* Broadcasts arrays and returns the broadcasted arrays in an array
*
@param
{
...Array | any
} arrays
*
@returns
*/
export
function
broadcastArrays
(
...
arrays
)
{
if
(
arrays
.
length
===
0
)
{
throw
new
Error
(
'Insuficient number of argumnets in function broadcastArrays'
)
}
if
(
arrays
.
length
===
1
)
{
return
arrays
[
0
]
}
const
sizes
=
arrays
.
map
(
function
(
array
)
{
return
arraySize
(
array
)
}
)
const
broadcastedSize
=
broadcastSizes
(
...
sizes
)
const
broadcastedArrays
=
[
]
arrays
.
forEach
(
function
(
array
)
{
broadcastedArrays
.
push
(
broadcastTo
(
array
,
broadcastedSize
)
)
}
)
return
broadcastedArrays
}
/**
* stretches a matrix up to a certain size in a certain dimension
*
@param
{
Array
} arrayToStretch
*
@param
{
number[]
} sizeToStretch
*
@param
{
number
} dimToStretch
*
@returns
*/
export
function
stretch
(
arrayToStretch
,
sizeToStretch
,
dimToStretch
)
{
return
concat
(
...
Array
(
sizeToStretch
)
.
fill
(
arrayToStretch
)
,
dimToStretch
)
}
/**
* Deep clones a multidimensional array
*
@param
{
Array
} array
*
@returns
cloned array
*/
export
function
clone
(
array
)
{
return
Object
.
assign
(
[
]
,
array
)
}
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