COORDS

Exchange atomic coordinate information.

>COORDS

Send atomic coordinates.

Datatype: MDI_DOUBLE
Quantity: 3 * NATOMS
Units: Bohr

Format: Sequentially ascending order of atomic index, with the coordinates for each individual atom being provided in xyz order.

The driver sends a set of atomic coordinates to the engine, which replaces its atomic coordinates with those sent by the driver.

Examples

Python

import mdi

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

# create an array of atomic coordinates

# send the atomic coordinates to the engine 
mdi.MDI_Send_Command(">COORDS", mdi_engine)
mdi.MDI_Send(coords, 3*natoms, mdi.MDI_DOUBLE, mdi_engine)  

C++

#include "mdi.h"
#include <vector>

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

// create a vector of atomic coordinates 

// send the atomic coordinates to the engine 
MDI_Send_Command(">COORDS", mdi_engine);
MDI_Send(coords.data(), 3*natoms, MDI_DOUBLE, mdi_engine);

<COORDS

Receive atomic coordinates.

Datatype: MDI_DOUBLE
Quantity: 3 * NATOMS
Units: Bohr

Format: Sequentially ascending order of atomic index, with the coordinates for each individual atom being provided in xyz order.

The engine sends a set of atomic coordinates to the driver.

Examples

Python

import mdi

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

# receive the atomic coordinates from the engine
mdi.MDI_Send_Command("<COORDS", mdi_engine)
coords = mdi.MDI_Recv(3*natoms, mdi.MDI_DOUBLE, mdi_engine)

Python (NumPy)

import mdi
import numpy as np

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

# create a buffer to hold the atomic coordinates
coords = np.zeros(3*natoms, dtype=float)

# receive the atomic coordinates from the engine
mdi.MDI_Send_Command("<COORDS", mdi_engine)
mdi.MDI_Recv(3*natoms, mdi.MDI_DOUBLE, mdi_engine, buf=coords) 

C++

#include "mdi.h"
#include <vector>

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

// create a buffer to hold the atomic coordinates
std::vector<double> coords(3*natoms);

// receive the atomic coordinates from the engine
MDI_Send_Command("<COORDS", mdi_engine);
MDI_Recv(coords.data(), 3*natoms, MDI_DOUBLE, mdi_engine);