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# Owning Dense Arrays
Owning arrays allocate storage and release it when the object is destroyed. They are commonly used in examples, tests, index objects, and user code that needs RAFT to allocate inputs, outputs, or staging buffers.
### raft::mdarray
_Source header: `raft/core/mdarray.hpp`_
Generic owning multi-dimensional array.
```cpp
template
class mdarray;
```
#### raft::mdarray::view
Returns an mdspan view over the owned storage.
```cpp
mdspan_type view();
const_mdspan_type view() const;
```
**Returns**
`mdspan_type or const_mdspan_type`
#### raft::mdarray::data_handle
Returns the pointer to the owned storage.
```cpp
element_type* data_handle();
element_type const* data_handle() const;
```
**Returns**
`element_type* or element_type const*`
#### raft::mdarray::extents
Returns the extents object that describes the array shape.
```cpp
extents_type extents() const;
```
**Returns**
`extents_type`
#### raft::mdarray::extent
Returns the size of one rank of the array.
```cpp
index_type extent(std::size_t r) const noexcept;
```
**Parameters**
| Name | Type | Description |
| --- | --- | --- |
| `r` | `std::size_t` | Rank to query. |
**Returns**
`index_type`
#### raft::mdarray::size
Returns the total number of elements in the array.
```cpp
size_type size() const;
```
**Returns**
`size_type`
#### raft::mdarray::operator()
Indexes into the array. For device arrays, use this sparingly because element access may require device-host movement.
```cpp
template
reference operator()(IndexType... indices);
template
const_reference operator()(IndexType... indices) const;
```
**Parameters**
| Name | Type | Description |
| --- | --- | --- |
| `indices` | `IndexType...` | Coordinates into the array, one per rank. |
**Returns**
`reference or const_reference`
### raft::device_mdarray
_Source header: `raft/core/device_mdarray.hpp`_
Owning array in device-accessible memory.
```cpp
template >
using device_mdarray =
mdarray>;
```
### raft::host_mdarray
_Source header: `raft/core/host_mdarray.hpp`_
Owning array in host memory.
```cpp
template >
using host_mdarray =
mdarray>;
```
### raft::device_matrix
_Source header: `raft/core/device_mdarray.hpp`_
Owning device matrix alias used for datasets, outputs, and temporary storage.
```cpp
template
using device_matrix = device_mdarray, LayoutPolicy>;
```
### raft::device_vector
_Source header: `raft/core/device_mdarray.hpp`_
Owning device vector alias used for outputs and temporary storage.
```cpp
template
using device_vector = device_mdarray, LayoutPolicy>;
```
### raft::host_matrix
_Source header: `raft/core/host_mdarray.hpp`_
Owning host matrix alias used for CPU-resident data and staging.
```cpp
template
using host_matrix = host_mdarray, LayoutPolicy>;
```
### raft::host_vector
_Source header: `raft/core/host_mdarray.hpp`_
Owning host vector alias used for CPU-resident data and staging.
```cpp
template
using host_vector = host_mdarray, LayoutPolicy>;
```