# mdtraj.formats.XTCTrajectoryFile¶

class mdtraj.formats.XTCTrajectoryFile(filenamee, mode='r', force_overwrite=True, **kwargs)

Interface for reading and writing to a GROMACS XTC file. This is a file-like objec that supports both reading and writing. It also supports the context manager ptorocol, so you can use it with the python ‘with’ statement.

The conventional units in the XTC file are nanometers and picoseconds. The format only supports saving coordinates, the time, the md step, and the unit cell parametrs (box vectors)

Parameters
filenamestr

The filename to open. A path to a file on disk.

mode{‘r’, ‘w’}

The mode in which to open the file, either ‘r’ for read or ‘w’ for write.

force_overwritebool

If opened in write mode, and a file by the name of filename already exists on disk, should we overwrite it?

Other Parameters
min_chunk_sizeint, default=100

In read mode, we need to allocate a buffer in which to store the data without knowing how many frames are in the file. This parameter is the minimum size of the buffer to allocate.

chunk_size_multiplierint, default=1.5

In read mode, we need to allocate a buffer in which to store the data without knowing how many frames are in the file. We can guess this information based on the size of the file on disk, but it’s not perfect. This parameter inflates the guess by a multiplicative factor.

mdtraj.load_xtc

High-level wrapper that returns a md.Trajectory

Examples

>>> # read the data from from an XTC file
>>> with XTCTrajectoryFile('traj.xtc') as f:
>>>    xyz, time, step, box = f.read()

>>> # write some random coordinates to an XTC file
>>> with XTCTrajectoryFile('output.xtc', 'w') as f:
>>>     f.write(np.random.randn(10,1,3))

Attributes
distance_unit
offsets

get byte offsets from current xtc file

Methods

 close() Close the XTC file handle read([n_frames, stride, atom_indices]) Read data from an XTC file read_as_traj(topology[, n_frames, stride, …]) Read a trajectory from an XTC file seek(offset[, whence]) Move to a new file position tell() Current file position write(xyz[, time, step, box]) Write data to an XTC file
 flush
__init__(self, /, \*args, \*\*kwargs)

Initialize self. See help(type(self)) for accurate signature.

Methods

 __init__(self, /, \*args, \*\*kwargs) Initialize self. close() Close the XTC file handle flush() read([n_frames, stride, atom_indices]) Read data from an XTC file read_as_traj(topology[, n_frames, stride, …]) Read a trajectory from an XTC file seek(offset[, whence]) Move to a new file position tell() Current file position write(xyz[, time, step, box]) Write data to an XTC file

Attributes

 distance_unit offsets get byte offsets from current xtc file