# Source code for mars.tensor.merge.column_stack

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 1999-2021 Alibaba Group Holding Ltd.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
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from ..datasource import tensor as astensor
from .concatenate import concatenate
[docs]def column_stack(tup):
"""
Stack 1-D tensors as columns into a 2-D tensor.
Take a sequence of 1-D tensors and stack them as columns
to make a single 2-D tensor. 2-D tensors are stacked as-is,
just like with `hstack`. 1-D tensors are turned into 2-D columns
first.
Parameters
----------
tup : sequence of 1-D or 2-D tensors.
Tensors to stack. All of them must have the same first dimension.
Returns
-------
stacked : 2-D tensor
The tensor formed by stacking the given tensors.
See Also
--------
stack, hstack, vstack, concatenate
Examples
--------
>>> import mars.tensor as mt
>>> a = mt.array((1,2,3))
>>> b = mt.array((2,3,4))
>>> mt.column_stack((a,b)).execute()
array([[1, 2],
[2, 3],
[3, 4]])
"""
from ..datasource import array
arrays = []
for a in tup:
a = astensor(a)
if a.ndim < 2:
a = array(a, ndmin=2).T
arrays.append(a)
return concatenate(arrays, 1)