(SPIN_POLARIZATION-target)=
# SPIN_POLARIZATION
```{tags} Quantum Mechanics, DFT, Plane Wave DFT
```

Exchange spin polarization information.



## <SPIN_POLARIZATION

Receive spin polarization setting.

**Datatype:** `MDI_INT`  
**Quantity**: `1`  
**Format:** A value of 0 indicates that simulations will be performed in a non-spin-polarized manner. 
A value of 1 indicates that simulations will be performed in a spin-polarized manner,
within the local spin density approximation (LSDA). 
A value of 2 indicates that simulations will be performed in a spin-polarized, noncollinear manner.


 The engine sends a value that indicates the manner in which it is currently simulating spin polarization. 
This command is typically intended for use with plane wave DFT engines.


### Examples


::::{tab-set}

:::{tab-item} Python
:sync: python

```python
import mdi

# connect to the engine
mdi_engine = mdi.MDI_Accept_Communicator()

# receive the spin polarization setting from the engine
mdi.MDI_Send_Command("<SPIN_POLARIZATION", mdi_engine)
spin_polarization = mdi.MDI_Recv(1, mdi.MDI_INT, mdi_engine)

```
:::

:::{tab-item} C++
:sync: cpp

```cpp
#include "mdi.h"

// connect to the engine
MDI_Comm mdi_engine = MDI_Accept_Communicator();

// create a buffer to hold the spin polarization setting
int spin_polarization;

// receive the spin polarization setting from the engine
MDI_Send_Command("<SPIN_POLARIZATION", mdi_engine);
MDI_Recv(&spin_polarization, 1, MDI_INT, mdi_engine);

```
:::

::::

## >SPIN_POLARIZATION

Send spin polarization setting.

**Datatype:** `MDI_INT`  
**Quantity**: `1`  
**Format:** A value of 0 indicates that simulations will be performed in a non-spin-polarized manner. 
A value of 1 indicates that simulations will be performed in a spin-polarized manner,
within the local spin density approximation (LSDA). 
A value of 2 indicates that simulations will be performed in a spin-polarized, noncollinear manner.


 The driver sends a value that indicates the manner in which spin polarization should be simulated by the engine. 
This command is typically intended for use with plane wave DFT engines.


### Examples


::::{tab-set}

:::{tab-item} Python
:sync: python

```python
import mdi

# connect to the engine
mdi_engine = mdi.MDI_Accept_Communicator()

# send the spin polarization setting to the engine
mdi.MDI_Send_Command(">SPIN_POLARIZATION", mdi_engine)
mdi.MDI_Send(1, 1, mdi.MDI_INT, mdi_engine)

```
:::

:::{tab-item} C++
:sync: cpp

```cpp
#include "mdi.h"

// connect to the engine
MDI_Comm mdi_engine = MDI_Accept_Communicator();

// send the spin polarization setting to the engine
int spin_polarization = 1;
MDI_Send_Command(">SPIN_POLARIZATION", mdi_engine);
MDI_Send(&spin_polarization, 1, MDI_INT, mdi_engine);

```
:::

::::