#######################################################
# Copyright (c) 2015, ArrayFire
# All rights reserved.
#
# This file is distributed under 3-clause BSD license.
# The complete license agreement can be obtained at:
# http://arrayfire.com/licenses/BSD-3-Clause
########################################################
"""
Vector algorithms (sum, min, sort, etc).
"""
from .library import *
from .array import *
def _parallel_dim(a, dim, c_func):
out = Array()
safe_call(c_func(ct.pointer(out.arr), a.arr, ct.c_int(dim)))
return out
def _reduce_all(a, c_func):
real = ct.c_double(0)
imag = ct.c_double(0)
safe_call(c_func(ct.pointer(real), ct.pointer(imag), a.arr))
real = real.value
imag = imag.value
return real if imag == 0 else real + imag * 1j
def _nan_parallel_dim(a, dim, c_func, nan_val):
out = Array()
safe_call(c_func(ct.pointer(out.arr), a.arr, ct.c_int(dim), ct.c_double(nan_val)))
return out
def _nan_reduce_all(a, c_func, nan_val):
real = ct.c_double(0)
imag = ct.c_double(0)
safe_call(c_func(ct.pointer(real), ct.pointer(imag), a.arr, ct.c_double(nan_val)))
real = real.value
imag = imag.value
return real if imag == 0 else real + imag * 1j
[docs]def sum(a, dim=None, nan_val=None):
"""
Calculate the sum of all the elements along a specified dimension.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the sum is required.
nan_val: optional: scalar. default: None
The value that replaces NaN in the array
Returns
-------
out: af.Array or scalar number
The sum of all elements in `a` along dimension `dim`.
If `dim` is `None`, sum of the entire Array is returned.
"""
if (nan_val is not None):
if dim is not None:
return _nan_parallel_dim(a, dim, backend.get().af_sum_nan, nan_val)
else:
return _nan_reduce_all(a, backend.get().af_sum_nan_all, nan_val)
else:
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_sum)
else:
return _reduce_all(a, backend.get().af_sum_all)
[docs]def product(a, dim=None, nan_val=None):
"""
Calculate the product of all the elements along a specified dimension.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the product is required.
nan_val: optional: scalar. default: None
The value that replaces NaN in the array
Returns
-------
out: af.Array or scalar number
The product of all elements in `a` along dimension `dim`.
If `dim` is `None`, product of the entire Array is returned.
"""
if (nan_val is not None):
if dim is not None:
return _nan_parallel_dim(a, dim, backend.get().af_product_nan, nan_val)
else:
return _nan_reduce_all(a, backend.get().af_product_nan_all, nan_val)
else:
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_product)
else:
return _reduce_all(a, backend.get().af_product_all)
[docs]def min(a, dim=None):
"""
Find the minimum value of all the elements along a specified dimension.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the minimum value is required.
Returns
-------
out: af.Array or scalar number
The minimum value of all elements in `a` along dimension `dim`.
If `dim` is `None`, minimum value of the entire Array is returned.
"""
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_min)
else:
return _reduce_all(a, backend.get().af_min_all)
[docs]def max(a, dim=None):
"""
Find the maximum value of all the elements along a specified dimension.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the maximum value is required.
Returns
-------
out: af.Array or scalar number
The maximum value of all elements in `a` along dimension `dim`.
If `dim` is `None`, maximum value of the entire Array is returned.
"""
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_max)
else:
return _reduce_all(a, backend.get().af_max_all)
[docs]def all_true(a, dim=None):
"""
Check if all the elements along a specified dimension are true.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the product is required.
Returns
-------
out: af.Array or scalar number
Af.array containing True if all elements in `a` along the dimension are True.
If `dim` is `None`, output is True if `a` does not have any zeros, else False.
"""
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_all_true)
else:
return _reduce_all(a, backend.get().af_all_true_all)
[docs]def any_true(a, dim=None):
"""
Check if any the elements along a specified dimension are true.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the product is required.
Returns
-------
out: af.Array or scalar number
Af.array containing True if any elements in `a` along the dimension are True.
If `dim` is `None`, output is True if `a` does not have any zeros, else False.
"""
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_any_true)
else:
return _reduce_all(a, backend.get().af_any_true_all)
[docs]def count(a, dim=None):
"""
Count the number of non zero elements in an array along a specified dimension.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the the non zero elements are to be counted.
Returns
-------
out: af.Array or scalar number
The count of non zero elements in `a` along `dim`.
If `dim` is `None`, the total number of non zero elements in `a`.
"""
if dim is not None:
return _parallel_dim(a, dim, backend.get().af_count)
else:
return _reduce_all(a, backend.get().af_count_all)
[docs]def imin(a, dim=None):
"""
Find the value and location of the minimum value along a specified dimension
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the minimum value is required.
Returns
-------
(val, idx): tuple of af.Array or scalars
`val` contains the minimum value of `a` along `dim`.
`idx` contains the location of where `val` occurs in `a` along `dim`.
If `dim` is `None`, `val` and `idx` value and location of global minimum.
"""
if dim is not None:
out = Array()
idx = Array()
safe_call(backend.get().af_imin(ct.pointer(out.arr), ct.pointer(idx.arr), a.arr, ct.c_int(dim)))
return out,idx
else:
real = ct.c_double(0)
imag = ct.c_double(0)
idx = ct.c_uint(0)
safe_call(backend.get().af_imin_all(ct.pointer(real), ct.pointer(imag), ct.pointer(idx), a.arr))
real = real.value
imag = imag.value
val = real if imag == 0 else real + imag * 1j
return val,idx.value
[docs]def imax(a, dim=None):
"""
Find the value and location of the maximum value along a specified dimension
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: None
Dimension along which the maximum value is required.
Returns
-------
(val, idx): tuple of af.Array or scalars
`val` contains the maximum value of `a` along `dim`.
`idx` contains the location of where `val` occurs in `a` along `dim`.
If `dim` is `None`, `val` and `idx` value and location of global maximum.
"""
if dim is not None:
out = Array()
idx = Array()
safe_call(backend.get().af_imax(ct.pointer(out.arr), ct.pointer(idx.arr), a.arr, ct.c_int(dim)))
return out,idx
else:
real = ct.c_double(0)
imag = ct.c_double(0)
idx = ct.c_uint(0)
safe_call(backend.get().af_imax_all(ct.pointer(real), ct.pointer(imag), ct.pointer(idx), a.arr))
real = real.value
imag = imag.value
val = real if imag == 0 else real + imag * 1j
return val,idx.value
[docs]def accum(a, dim=0):
"""
Cumulative sum of an array along a specified dimension
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: 0
Dimension along which the cumulative sum is required.
Returns
-------
out: af.Array
array of same size as `a` containing the cumulative sum along `dim`.
"""
return _parallel_dim(a, dim, backend.get().af_accum)
[docs]def where(a):
"""
Find the indices of non zero elements
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
Returns
-------
idx: af.Array
Linear indices for non zero elements.
"""
out = Array()
safe_call(backend.get().af_where(ct.pointer(out.arr), a.arr))
return out
[docs]def diff1(a, dim=0):
"""
Find the first order differences along specified dimensions
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: 0
Dimension along which the differences are required.
Returns
-------
out: af.Array
Array whose length along `dim` is 1 less than that of `a`.
"""
return _parallel_dim(a, dim, backend.get().af_diff1)
[docs]def diff2(a, dim=0):
"""
Find the second order differences along specified dimensions
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: 0
Dimension along which the differences are required.
Returns
-------
out: af.Array
Array whose length along `dim` is 2 less than that of `a`.
"""
return _parallel_dim(a, dim, backend.get().af_diff2)
[docs]def sort(a, dim=0, is_ascending=True):
"""
Sort the array along a specified dimension
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: 0
Dimension along which sort is to be performed.
is_ascending: optional: bool. default: True
Specifies the direction of the sort
Returns
-------
out: af.Array
array containing the sorted values
Note
-------
Currently `dim` is only supported for 0.
"""
out = Array()
safe_call(backend.get().af_sort(ct.pointer(out.arr), a.arr, ct.c_uint(dim), ct.c_bool(is_ascending)))
return out
[docs]def sort_index(a, dim=0, is_ascending=True):
"""
Sort the array along a specified dimension and get the indices.
Parameters
----------
a : af.Array
Multi dimensional arrayfire array.
dim: optional: int. default: 0
Dimension along which sort is to be performed.
is_ascending: optional: bool. default: True
Specifies the direction of the sort
Returns
-------
(val, idx): tuple of af.Array
`val` is an af.Array containing the sorted values.
`idx` is an af.Array containing the original indices of `val` in `a`.
Note
-------
Currently `dim` is only supported for 0.
"""
out = Array()
idx = Array()
safe_call(backend.get().af_sort_index(ct.pointer(out.arr), ct.pointer(idx.arr), a.arr,
ct.c_uint(dim), ct.c_bool(is_ascending)))
return out,idx
[docs]def sort_by_key(iv, ik, dim=0, is_ascending=True):
"""
Sort an array based on specified keys
Parameters
----------
iv : af.Array
An Array containing the values
ik : af.Array
An Array containing the keys
dim: optional: int. default: 0
Dimension along which sort is to be performed.
is_ascending: optional: bool. default: True
Specifies the direction of the sort
Returns
-------
(ov, ok): tuple of af.Array
`ov` contains the values from `iv` after sorting them based on `ik`
`ok` contains the values from `ik` in sorted order
Note
-------
Currently `dim` is only supported for 0.
"""
ov = Array()
ok = Array()
safe_call(backend.get().af_sort_by_key(ct.pointer(ov.arr), ct.pointer(ok.arr),
iv.arr, ik.arr, ct.c_uint(dim), ct.c_bool(is_ascending)))
return ov,ok
[docs]def set_unique(a, is_sorted=False):
"""
Find the unique elements of an array.
Parameters
----------
a : af.Array
A 1D arrayfire array.
is_sorted: optional: bool. default: False
Specifies if the input is pre-sorted.
Returns
-------
out: af.Array
an array containing the unique values from `a`
"""
out = Array()
safe_call(backend.get().af_set_unique(ct.pointer(out.arr), a.arr, ct.c_bool(is_sorted)))
return out
[docs]def set_union(a, b, is_unique=False):
"""
Find the union of two arrays.
Parameters
----------
a : af.Array
A 1D arrayfire array.
b : af.Array
A 1D arrayfire array.
is_unique: optional: bool. default: False
Specifies if the both inputs contain unique elements.
Returns
-------
out: af.Array
an array values after performing the union of `a` and `b`.
"""
out = Array()
safe_call(backend.get().af_set_union(ct.pointer(out.arr), a.arr, b.arr, ct.c_bool(is_unique)))
return out
[docs]def set_intersect(a, b, is_unique=False):
"""
Find the intersect of two arrays.
Parameters
----------
a : af.Array
A 1D arrayfire array.
b : af.Array
A 1D arrayfire array.
is_unique: optional: bool. default: False
Specifies if the both inputs contain unique elements.
Returns
-------
out: af.Array
an array values after performing the intersect of `a` and `b`.
"""
out = Array()
safe_call(backend.get().af_set_intersect(ct.pointer(out.arr), a.arr, b.arr, ct.c_bool(is_unique)))
return out
