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{{Infobox script-repo
 
{{Infobox script-repo
 
|type      = script
 
|type      = script
−
|download = Submitted to the [[Git_intro|Pymol-script-repo]] as flatten_obj.py
+
|filename = flatten_obj.py
 
|author    = [[User:sbliven|Spencer Bliven]]
 
|author    = [[User:sbliven|Spencer Bliven]]
 
|license  = Public Domain
 
|license  = Public Domain
Line 59: Line 59:
 
     flatten_obj flat, nmrObj
 
     flatten_obj flat, nmrObj
 
     flatten_obj ( obj1 or obj2 )
 
     flatten_obj ( obj1 or obj2 )
−
 
−
= PyMol API =
 
−
 
−
    cmd.flatten_obj(string name, string selection)
 
−
 
−
 
−
 
−
= Code =
 
−
 
−
<syntaxhighlight lang="python">
 
−
"""
 
−
flatten_obj.py - Flatten multi-state pymol objects into a single state.
 
−
 
−
This is particularly useful for dealing with biological assemblies, which are
 
−
loaded as multi-state objects when fetched using `fetch PDBID, type=pdb1`. It
 
−
can also be used as a quick way to combine multiple objects without causing
 
−
collisions between chain identifiers.
 
−
 
−
The command re-letters chains to avoid collisions. Older versions of PyMOL
 
−
restrict the chain id to a single character, so the script will fail for
 
−
assemblies with >62 chains. With more recent versions, this problem is solved
 
−
with multi-character chain IDs. Several options are available for how
 
−
re-lettering should occur.
 
−
 
−
Author: Spencer Bliven <spencer.bliven@gmail.com>
 
−
Date: October 30, 2015
 
−
Version: 1.0
 
−
License: Public Domain
 
−
"""
 
−
from pymol import cmd, stored
 
−
import re
 
−
try:
 
−
    from collections import OrderedDict
 
−
    _orderedDict = True
 
−
except ImportError:
 
−
    _orderedDict = False
 
−
 
−
# PyMOL 1.7.4 introduces support for multi-letter chains, so we can afford to
 
−
# use a smaller alphabet. In earlier versions, use lower-case letters if needed
 
−
# (requires running `set ignore_case, 0`)
 
−
_long_chains = cmd.get_version()[1] >= 1.74
 
−
_default_base = 36 if _long_chains else 62
 
−
 
−
class OutOfChainsError(Exception):
 
−
    def __init__(self,msg):
 
−
        self.msg=msg
 
−
    def __str__(self):
 
−
        return str(self.msg)
 
−
 
−
class ChainSet(object):
 
−
    """
 
−
    Base class for various methods to rename chains
 
−
 
−
    Contains _chains, which maps from the renamed chain to a tuple with the
 
−
    original (object,state,chain). All dict-like accessors work on ChainSets,
 
−
    e.g.
 
−
        chain_set["A"] -> ("obj",1,"A")
 
−
 
−
    """
 
−
    def __init__(self):
 
−
        # Use an OrderedDict in Python >= 1.7 for better printing
 
−
        if _orderedDict:
 
−
            self._chains = OrderedDict()
 
−
        else:
 
−
            self._chains = dict()
 
−
 
−
    def map_chain(self, obj, state, origChain ):
 
−
        """
 
−
        map_chain(string obj,int state, string chain]]) -> string
 
−
 
−
        Maps a chain letter to a unique chainID. Results are unique within each
 
−
        instance, and can be used as keys on this chain set.
 
−
        """
 
−
        raise NotImplementedError("Base class")
 
−
 
−
    # delegate most methods to _chains
 
−
    def __getattr__(self,at):
 
−
        if at in "pop popitem update setdefault".split():
 
−
            raise AttributeError("type object '%s' has no attribute '%s'"%(type(self),at))
 
−
        return getattr(self._chains,at)
 
−
    def __cmp__(self,other):    return self._chains.__cmp__(other)
 
−
    def __eq__(self,other):    return self._chains.__eq__(other)
 
−
    def __ge__(self,other):    return self._chains.__ge__(other)
 
−
    def __gt__(self,other):    return self._chains.__gt__(other)
 
−
    def __le__(self,other):    return self._chains.__le__(other)
 
−
    def __lt__(self,other):    return self._chains.__lt__(other)
 
−
    def __ne__(self,other):    return self._chains.__ne__(other)
 
−
    def __len__(self):          return self._chains.__len__()
 
−
    def __contains__(self,key): return self._chains.__contains__(key)
 
−
    def __getitem__(self,key):  return self._chains.__getitem__(key)
 
−
    def __iter__(self):        return self._chains.__iter__()
 
−
    def __str__(self):          return str(self._chains)
 
−
 
−
    @staticmethod
 
−
    def _int_to_chain(i,base=_default_base):
 
−
        """
 
−
        _int_to_chain(int,int) -> str
 
−
 
−
        Converts a positive integer to a chain ID. Chain IDs include uppercase
 
−
        characters, numbers, and optionally lowercase letters.
 
−
 
−
        i = a positive integer to convert
 
−
        base = the alphabet size to include. Typically 36 or 62.
 
−
        """
 
−
        if i < 0:
 
−
            raise ValueError("positive integers only")
 
−
        if base < 0 or 62 < base:
 
−
            raise ValueError("Invalid base")
 
−
 
−
        quot = int(i)/base
 
−
        rem = i%base
 
−
        if rem < 26:
 
−
            letter = chr( ord("A") + rem)
 
−
        elif rem < 36:
 
−
            letter = str( rem-26)
 
−
        else:
 
−
            letter = chr( ord("a") + rem - 36)
 
−
        if quot == 0:
 
−
            return letter
 
−
        else:
 
−
            return ChainSet._int_to_chain(quot-1,base) + letter
 
−
 
−
 
−
class DefaultChainSet(ChainSet):
 
−
    """
 
−
    Avoids relettering chains if possible. If a chain has been used, uses the
 
−
    next available chain letter. Note that this can potentially lead to
 
−
    cascading renames, e.g. if chains are sorted alphabetically rather than by
 
−
    object.
 
−
 
−
    Used for rename = 0.
 
−
    """
 
−
    def __init__(self):
 
−
        super(DefaultChainSet,self).__init__()
 
−
        self._next_chain = 0
 
−
    def map_chain(self, obj, state, origChain ):
 
−
        # Keep _next_chain up-to-date
 
−
        while ChainSet._int_to_chain(self._next_chain) in self:
 
−
            self._next_chain += 1
 
−
        # Map this chain
 
−
        if origChain in self:
 
−
            # Rename
 
−
            next_chain = ChainSet._int_to_chain(self._next_chain)
 
−
            self._next_chain += 1
 
−
        else:
 
−
            next_chain = origChain
 
−
        self._chains[next_chain] = (obj,state,origChain)
 
−
        return next_chain
 
−
 
−
class SequentialChainSet(ChainSet):
 
−
    """
 
−
    Renumbers all chains starting at A, continuing through the capital letters
 
−
    and numbers, and then adding additional letters through 9999 (the last
 
−
    valid chain for mmCIF) and beyond.
 
−
 
−
    Used for rename=1
 
−
    """
 
−
    def __init__(self):
 
−
        super(SequentialChainSet,self).__init__()
 
−
        self._next_chain = 0
 
−
 
−
    def map_chain(self, obj, state, origChain ):
 
−
        next_chain = ChainSet._int_to_chain(self._next_chain)
 
−
        self._chains[next_chain] = (obj,state,origChain)
 
−
        self._next_chain += 1
 
−
        return next_chain
 
−
 
−
class LongChainSet(ChainSet):
 
−
    """
 
−
    Uses long strings for the chain names. Chains are renamed like
 
−
    "%s_%s_%04d"%(original_chainid,objectname,state).
 
−
 
−
    Used for rename=2
 
−
    """
 
−
    def map_chain(self, obj, state, origChain ):
 
−
        ch = "%s_%s_%04d"%(origChain,obj,state)
 
−
        if self.has_key(ch):
 
−
            raise ValueError("Duplicate chain %s"%(ch))
 
−
        self._chains[ch] = (obj,state,origChain)
 
−
        return ch
 
−
 
−
 
−
 
−
 
−
def flatten_obj(name="",selection="",state=0,rename=0,quiet=1,chain_map=""):
 
−
    """
 
−
DESCRIPTION
 
−
 
−
    "flatten_obj" combines multiple objects or states into a single object,
 
−
    renaming chains where required
 
−
 
−
USAGE
 
−
 
−
    flatten_obj name, selection[, state[, rename[, quiet[, chain_map]]]]
 
−
 
−
ARGUMENTS
 
−
 
−
    name = a unique name for the flattened object {default: flat}
 
−
 
−
    selection = the set of objects to include in the flattening. The selection
 
−
        will be expanded to include all atoms of objects. {default: all}
 
−
 
−
    state = the source state to select. Use 0 or -1 to flatten all states {default: 0}
 
−
 
−
    rename = The scheme to use for renaming chains: {default: 0}
 
−
        (0) preserve chains IDs where possible, rename other chains
 
−
            alphabetically
 
−
        (1) rename all chains alphabetically
 
−
        (2) rename chains using the original chain letter, object name, and state
 
−
 
−
    quiet = If set to 0, print some additional information about progress and
 
−
        chain renaming {default: 1}
 
−
 
−
    chain_map = An attribute name for the 'stored' scratch object. If
 
−
        specified, `stored.<chain_map>` will be populated with a dictionary
 
−
        mapping the new chain names to a tuple giving the originated object,
 
−
        state, and chainID. {default: ""}
 
−
 
−
NOTES
 
−
 
−
    Like the select command, if name is omitted then the default object name
 
−
    ("flat") is used as the name argument.
 
−
 
−
    Chain renaming is tricky. PDB files originally limited chains to single
 
−
    letter identifiers containing [A-Za-z0-9]. When this was found to be
 
−
    limiting, multi-letter chains (ideally < 4 chars) were allowed. This is
 
−
    supported as of PyMOL 1.7. Earlier versions do not accept rename=2, and
 
−
    will raise an exception when flattening a structure with more than 62
 
−
    chains.
 
−
 
−
EXAMPLES
 
−
 
−
    flatten_obj flat, nmrObj
 
−
    flatten_obj ( obj1 or obj2 )
 
−
 
−
PYMOL API
 
−
 
−
    cmd.flatten_obj(string name, string selection)
 
−
 
−
SEE ALSO
 
−
 
−
    split_states
 
−
 
−
    """
 
−
 
−
    # arguments
 
−
 
−
    # Single argument; treat as selection
 
−
    if name and not selection:
 
−
        selection = name
 
−
        name = ""
 
−
    # default name and selection
 
−
    if not name:
 
−
        name = "flat"
 
−
    if not selection:
 
−
        selection = "(all)"
 
−
 
−
    state = int(state)
 
−
    rename = int(rename)
 
−
    quiet = int(quiet)
 
−
 
−
    # Wrap in extra parantheses for get_object_list
 
−
    selection = "( %s )" % selection
 
−
 
−
    if rename == 0:
 
−
        chainSet = DefaultChainSet()
 
−
    elif rename == 1:
 
−
        chainSet = SequentialChainSet()
 
−
    elif rename == 2:
 
−
        chainSet = LongChainSet()
 
−
    else:
 
−
        raise ValueError("Unrecognized rename option (Valid: 0,1,2)")
 
−
 
−
    metaprefix = "temp" #TODO unique prefix
 
−
 
−
    # store original value of retain_order, which causes weird interleaving of
 
−
    # structures if enabled.
 
−
    retain_order = cmd.get("retain_order")
 
−
    try:
 
−
        cmd.set("retain_order",0)
 
−
 
−
        # create new object for each state
 
−
        for obj in cmd.get_object_list(selection):
 
−
 
−
            if state <= 0:
 
−
                # all states
 
−
                prefix = "%s_%s_"%(metaprefix,obj)
 
−
                cmd.split_states(obj,prefix=prefix)
 
−
            else:
 
−
                prefix = "%s_%s_%04d"%(metaprefix,obj,state)
 
−
                cmd.create(prefix, obj, state, 1)
 
−
 
−
        # renumber all states
 
−
        statere = re.compile("^%s_(.*)_(\d+)$" % metaprefix) # matches split object names
 
−
 
−
        warn_lowercase = False
 
−
 
−
        # Iterate over all objects with metaprefix
 
−
        try:
 
−
            for obj in cmd.get_object_list("(%s_*)"%(metaprefix) ):
 
−
                m = statere.match(obj)
 
−
                if m is None:
 
−
                    print("Failed to match object %s" %obj)
 
−
                    continue
 
−
                origobj = m.group(1)
 
−
                statenum = int(m.group(2))
 
−
 
−
                chains = set([atom.chain for atom in cmd.get_model(obj).atom])
 
−
 
−
                rev_chain_map = {} #old -> new, for this obj only
 
−
                for chain in sorted(chains):
 
−
                    new_chain = chainSet.map_chain(origobj,statenum,chain)
 
−
                    rev_chain_map[chain] = new_chain
 
−
                    if not quiet:
 
−
                        print("  %s state %d chain %s -> %s"%(origobj,statenum,chain, new_chain) )
 
−
                    if not _long_chains:
 
−
                        if len(new_chain) > 1:
 
−
                            raise OutOfChainsError("No additional chains available (max 62).")
 
−
 
−
                try:
 
−
                    stored_name = stored.get_unused_name()
 
−
                except AttributeError:
 
−
                    # backup solution for PyMOL < 1.6
 
−
                    stored_name = "_flatten_obj_chainMapping"
 
−
 
−
                setattr(stored,stored_name,rev_chain_map)
 
−
                cmd.alter(obj,"chain = stored.%s[chain]"%stored_name)
 
−
                delattr(stored,stored_name)
 
−
 
−
            print("Creating object from %s_*"%metaprefix)
 
−
            # Recombine into a single object
 
−
            cmd.create(name,"%s_*"%metaprefix)
 
−
 
−
            # Set chain_map
 
−
            if chain_map:
 
−
                setattr(stored,chain_map,chainSet)
 
−
 
−
            # Warn if lowercase chains were generated
 
−
            if cmd.get("ignore_case") == "on" and any([c.upper() != c for c in chainSet.keys()]):
 
−
                print("Warning: using lower-case chain IDs. Consider running the "
 
−
                        "following command:\n  set ignore_case, 0" )
 
−
 
−
        finally:
 
−
            # Clean up
 
−
            print("Cleaning up intermediates")
 
−
            cmd.delete("%s_*"%metaprefix)
 
−
    finally:
 
−
        # restore original parameters
 
−
        print("Resetting variables")
 
−
        cmd.set("retain_order",retain_order)
 
−
 
−
 
−
cmd.extend('flatten_obj', flatten_obj)
 
−
 
−
# tab-completion of arguments
 
−
cmd.auto_arg[0]['flatten_obj'] = [ cmd.object_sc, 'name or selection', '']
 
−
cmd.auto_arg[1]['flatten_obj'] = [ cmd.object_sc, 'selection', '']
 
−
</syntaxhighlight>
 
  
 
= See Also =
 
= See Also =

Latest revision as of 05:01, 16 November 2015

Type Python Script
Download flatten_obj.py
Author(s) Spencer Bliven
License Public Domain
This code has been put under version control in the project Pymol-script-repo

Description

The flatten_obj python script combines multiple objects or states into a single object, renaming chains where required.

This is particularly useful for dealing with biological assemblies, which are loaded as multi-state objects when fetched using fetch PDBID, type=pdb1. It can also be used as a quick way to combine multiple objects without causing collisions between chain identifiers.

The command re-letters chains to avoid collisions. Older versions of PyMOL restrict the chain id to a single character, so the script will fail for assemblies with >62 chains. With more recent versions, this problem is solved with multi-character chain IDs. Several options are available for how re-lettering should occur.

Usage

   flatten_obj name, selection[, state[, rename[, quiet[, chain_map]]]]

Arguments

  • name = a unique name for the flattened object {default: flat}
  • selection = the set of objects to include in the flattening. The selection will be expanded to include all atoms of objects. {default: all}
  • state = the source state to select. Use 0 or -1 to flatten all states {default: 0}
  • rename = The scheme to use for renaming chains: {default: 0}
    • (0) preserve chains IDs where possible, rename other chains alphabetically
    • (1) rename all chains alphabetically
    • (2) rename chains using the original chain letter, object name, and state
  • quiet = If set to 0, print some additional information about progress and chain renaming {default: 1}
  • chain_map = An attribute name for the 'stored' scratch object. If specified, `stored.<chain_map>` will be populated with a dictionary mapping the new chain names to a tuple giving the originated object, state, and chainID. {default: ""}

Notes

Like the select command, if name is omitted then the default object name ("flat") is used as the name argument.

Chain renaming is tricky. PDB files originally limited chains to single letter identifiers containing [A-Za-z0-9]. When this was found to be limiting, multi-letter chains (ideally < 4 chars) were allowed. This is supported as of PyMOL 1.7. Earlier versions do not accept rename=2, and will raise an exception when flattening a structure with more than 62 chains.

Examples

   flatten_obj flat, nmrObj
   flatten_obj ( obj1 or obj2 )

See Also

Retrieved from "http://wiki.pymol.org/index.php?title=Flatten_obj&oldid=13311"