5.15. MMCIF Topology Parser

Read topology information from mmCIF/PDBx coordinate files using the Gemmi library

mmCIF files contain topology information about the molecules in the structure. For each atom the following attributes are read and stored in the relevant topology attributes:

5.15.1. Classes

class MDAnalysis.topology.MMCIFParser.MMCIFParser(filename)[source]

Parser that obtains a list of atoms from a standard MMCIF/PDBx file using gemmi library (https://github.com/project-gemmi/gemmi).

Creates the following Attributes (if present):
  • core.topologyattrs.AtomAttr subclasses:

    • core.topologyattrs.AltLocs

    • core.topologyattrs.Atomids

    • core.topologyattrs.Atomnames

    • core.topologyattrs.Atomtypes

    • core.topologyattrs.ChainIDs

    • core.topologyattrs.Elements

    • core.topologyattrs.FormalCharges

    • core.topologyattrs.Masses

    • core.topologyattrs.Occupancies

    • core.topologyattrs.RecordTypes

    • core.topologyattrs.Tempfactors

  • core.topologyattrs.ResidueAttr subclasses:

    • core.topologyattrs.Resnums

    • core.topologyattrs.ICodes

    • core.topologyattrs.Resids

    • core.topologyattrs.Resnames

  • core.topologyattrs.SegmentAttr subclasses:

    • core.topologyattrs.Segids

New in version 2.9.0.

close()

Close the trajectory file.

convert_forces_from_native(force, inplace=True)

Conversion of forces array force from native to base units

Parameters:

  • force (array_like) – Forces to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input force is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

New in version 0.7.7.

convert_forces_to_native(force, inplace=True)

Conversion of force array force from base to native units.

Parameters:

  • force (array_like) – Forces to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input force is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

New in version 0.7.7.

convert_pos_from_native(x, inplace=True)

Conversion of coordinate array x from native units to base units.

Parameters:

  • x (array_like) – Positions to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input x is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

Changed in version 0.7.5: Keyword inplace can be set to False so that a modified copy is returned unless no conversion takes place, in which case the reference to the unmodified x is returned.

convert_pos_to_native(x, inplace=True)

Conversion of coordinate array x from base units to native units.

Parameters:

  • x (array_like) – Positions to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input x is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

Changed in version 0.7.5: Keyword inplace can be set to False so that a modified copy is returned unless no conversion takes place, in which case the reference to the unmodified x is returned.

convert_time_from_native(t, inplace=True)

Convert time t from native units to base units.

Parameters:

  • t (array_like) – Time values to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input t is modified in place and also returned (although note that scalar values t are passed by value in Python and hence an in-place modification has no effect on the caller.) In-place operations improve performance because allocating new arrays is avoided.

Changed in version 0.7.5: Keyword inplace can be set to False so that a modified copy is returned unless no conversion takes place, in which case the reference to the unmodified x is returned.

convert_time_to_native(t, inplace=True)

Convert time t from base units to native units.

Parameters:

  • t (array_like) – Time values to transform

  • inplace (bool, optional) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input t is modified in place and also returned. (Also note that scalar values t are passed by value in Python and hence an in-place modification has no effect on the caller.)

Changed in version 0.7.5: Keyword inplace can be set to False so that a modified copy is returned unless no conversion takes place, in which case the reference to the unmodified x is returned.

convert_velocities_from_native(v, inplace=True)

Conversion of velocities array v from native to base units

Parameters:

  • v (array_like) – Velocities to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input v is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

New in version 0.7.5.

convert_velocities_to_native(v, inplace=True)

Conversion of coordinate array v from base to native units

Parameters:

  • v (array_like) – Velocities to transform

  • inplace (bool (optional)) – Whether to modify the array inplace, overwriting previous data

Note

By default, the input v is modified in place and also returned. In-place operations improve performance because allocating new arrays is avoided.

New in version 0.7.5.

parse(**kwargs) → Topology[source]

Read the file and return the structure.

Return type:

MDAnalysis Topology object

units = {'length': None, 'time': None, 'velocity': None}

dict with units of of time and length (and velocity, force, … for formats that support it)

New in version 2.9.0.