calculate_rmsd

esta.rmsd.calculate_rmsd

str_atom(atom)

Convert atom type from integer to string

Parameters:

• atoms (string) –

Returns:

• atoms ( integer ) –

int_atom(atom)

Convert atom type from string to integer

Parameters:

• atoms (string) –

Returns:

• atoms ( integer ) –

rmsd(V, W)

Calculate Root-mean-square deviation from two sets of vectors V and W.

Parameters:

• V (array) –

  (N,D) matrix, where N is points and D is dimension.

• W (array) –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• rmsd ( float ) –

  Root-mean-square deviation between the two vectors

kabsch_rmsd(P, Q, W=None, translate=False)

Rotate matrix P unto Q using Kabsch algorithm and calculate the RMSD. An optional vector of weights W may be provided.

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

• W (array or None, default: None ) –

  (N) vector, where N is points.

• translate (bool, default: False ) –

  Use centroids to translate vector P and Q unto each other.

Returns:

• rmsd ( float ) –

  root-mean squared deviation

kabsch_rotate(P, Q)

Rotate matrix P unto matrix Q using Kabsch algorithm.

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• P ( array ) –

  (N,D) matrix, where N is points and D is dimension, rotated

kabsch_fit(P, Q, W=None)

Rotate and translate matrix P unto matrix Q using Kabsch algorithm. An optional vector of weights W may be provided.

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

• W (array or None, default: None ) –

  (N) vector, where N is points.

Returns:

• P ( array ) –

  (N,D) matrix, where N is points and D is dimension, rotated and translated.

kabsch(P, Q)

Using the Kabsch algorithm with two sets of paired point P and Q, centered around the centroid. Each vector set is represented as an NxD matrix, where D is the the dimension of the space. The algorithm works in three steps: - a centroid translation of P and Q (assumed done before this function call) - the computation of a covariance matrix C - computation of the optimal rotation matrix U For more info see http://en.wikipedia.org/wiki/Kabsch_algorithm

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• U ( matrix ) –

  Rotation matrix (D,D)

kabsch_weighted(P, Q, W=None)

Using the Kabsch algorithm with two sets of paired point P and Q. Each vector set is represented as an NxD matrix, where D is the dimension of the space. An optional vector of weights W may be provided.

Note that this algorithm does not require that P and Q have already been overlayed by a centroid translation.

The function returns the rotation matrix U, translation vector V, and RMS deviation between Q and P', where P' is:

P' = P * U + V

For more info see http://en.wikipedia.org/wiki/Kabsch_algorithm

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

• W (array or None, default: None ) –

  (N) vector, where N is points.

Returns:

• U ( matrix ) –

  Rotation matrix (D,D)

• V ( vector ) –

  Translation vector (D)

• RMSD ( float ) –

  Root mean squared deviation between P and Q

kabsch_weighted_fit(P, Q, W=None, rmsd=False)

Fit P to Q with optional weights W. Also returns the RMSD of the fit if rmsd=True.

Parameters:

• P –

  (N,D) matrix, where N is points and D is dimension.

• Q –

  (N,D) matrix, where N is points and D is dimension.

• W –

  (N) vector, where N is points

• rmsd (Bool, default: False ) –

  If True, rmsd is returned as well as the fitted coordinates.

Returns:

• P' : array –

  (N,D) matrix, where N is points and D is dimension.

• RMSD ( float ) –

  if the function is called with rmsd=True

kabsch_weighted_rmsd(P, Q, W=None)

Calculate the RMSD between P and Q with optional weighhts W

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

• W (vector, default: None ) –

  (N) vector, where N is points

Returns:

• RMSD ( float ) –

quaternion_rmsd(P, Q)

Rotate matrix P unto Q and calculate the RMSD based on doi:10.1016/1049-9660(91)90036-O

Parameters:

• P (array) –

  (N,D) matrix, where N is points and D is dimension.

• Q (array) –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• rmsd ( float ) –

quaternion_transform(r)

Get optimal rotation note: translation will be zero when the centroids of each molecule are the same

makeW(r1, r2, r3, r4=0)

matrix involved in quaternion rotation

makeQ(r1, r2, r3, r4=0)

matrix involved in quaternion rotation

quaternion_rotate(X, Y)

Calculate the rotation

Parameters:

• X (array) –

  (N,D) matrix, where N is points and D is dimension.

• Y –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• rot ( matrix ) –

  Rotation matrix (D,D)

centroid(X)

Centroid is the mean position of all the points in all of the coordinate directions, from a vectorset X.

https://en.wikipedia.org/wiki/Centroid

C = sum(X)/len(X)

Parameters:

• X (array) –

  (N,D) matrix, where N is points and D is dimension.

Returns:

• C ( float ) –

  centroid

hungarian_vectors(p_vecs, q_vecs, sigma=1.0, use_kernel=True)

Hungarian cost assignment of a similiarty molecule kernel.

Note: Assumes p and q are atoms of same type

Parameters:

• p_vecs (array) –

  (N,L) matrix, where N is no. of atoms and L is representation length

• q_vecs (array) –

  (N,L) matrix, where N is no. of atoms and L is representation length

Returns:

• indices_b ( array ) –

  (N) view vector of reordered assignment

reorder_similarity(p_atoms, q_atoms, p_coord, q_coord, use_kernel=True)

Re-orders the input atom list and xyz coordinates using QML similarity the Hungarian method for assignment.

Parameters:

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_coord (array) –

  (N,D) matrix, where N is points and D is dimension

• q_coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• view_reorder ( array ) –

  (N,1) matrix, reordered indexes of atom alignment based on the coordinates of the atoms

reorder_distance(p_atoms, q_atoms, p_coord, q_coord)

Re-orders the input atom list and xyz coordinates by atom type and then by distance of each atom from the centroid.

Parameters:

• atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• atoms_reordered ( array ) –

  (N,1) matrix, where N is points holding the ordered atoms' names

• coords_reordered ( array ) –

  (N,D) matrix, where N is points and D is dimension (rows re-ordered)

hungarian(A, B)

Hungarian reordering.

Assume A and B are coordinates for atoms of SAME type only

reorder_hungarian(p_atoms, q_atoms, p_coord, q_coord)

Re-orders the input atom list and xyz coordinates using the Hungarian method (using optimized column results)

Parameters:

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_coord (array) –

  (N,D) matrix, where N is points and D is dimension

• q_coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• view_reorder ( array ) –

  (N,1) matrix, reordered indexes of atom alignment based on the coordinates of the atoms

reorder_inertia_hungarian(p_atoms, q_atoms, p_coord, q_coord)

Align the principal intertia axis and then re-orders the input atom list and xyz coordinates using the Hungarian method (using optimized column results)

Parameters:

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_coord (array) –

  (N,D) matrix, where N is points and D is dimension

• q_coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• view_reorder ( array ) –

  (N,1) matrix, reordered indexes of atom alignment based on the coordinates of the atoms

generate_permutations(elements, n)

Heap's algorithm for generating all n! permutations in a list https://en.wikipedia.org/wiki/Heap%27s_algorithm

brute_permutation(A, B)

Re-orders the input atom list and xyz coordinates using the brute force method of permuting all rows of the input coordinates

Parameters:

• A (array) –

  (N,D) matrix, where N is points and D is dimension

• B (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• view ( array ) –

  (N,1) matrix, reordered view of B projected to A

reorder_brute(p_atoms, q_atoms, p_coord, q_coord)

Re-orders the input atom list and xyz coordinates using all permutation of rows (using optimized column results)

Parameters:

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• q_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_coord (array) –

  (N,D) matrix, where N is points and D is dimension

• q_coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• view_reorder ( array ) –

  (N,1) matrix, reordered indexes of atom alignment based on the coordinates of the atoms

check_reflections(p_atoms, q_atoms, p_coord, q_coord, reorder_method=reorder_hungarian, rotation_method=kabsch_rmsd, keep_stereo=False)

Minimize RMSD using reflection planes for molecule P and Q

Warning: This will affect stereo-chemistry

Parameters:

• p_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• q_atoms (array) –

  (N,1) matrix, where N is points holding the atoms' names

• p_coord (array) –

  (N,D) matrix, where N is points and D is dimension

• q_coord (array) –

  (N,D) matrix, where N is points and D is dimension

Returns:

• min_rmsd –
• min_swap –
• min_reflection –
• min_review –

rotation_matrix_vectors(v1, v2)

Returns the rotation matrix that rotates v1 onto v2 using Rodrigues' rotation formula.

(see https://math.stackexchange.com/a/476311)

v1 : array Dim 3 float array v2 : array Dim 3 float array

Return

output : 3x3 matrix Rotation matrix

get_cm(atoms, V)

Get the center of mass of V.

atoms : list List of atomic types V : array (N,3) matrix of atomic coordinates

Return

output : (3) array The CM vector

get_inertia_tensor(atoms, V)

Get the tensor of intertia of V.

atoms : list List of atomic types V : array (N,3) matrix of atomic coordinates

Return

output : 3x3 float matrix The tensor of inertia

get_principal_axis(atoms, V)

Get the molecule's principal axis.

atoms : list List of atomic types V : array (N,3) matrix of atomic coordinates

Return

output : array Array of dim 3 containing the principal axis

set_coordinates(atoms, V, title='', decimals=8)

Print coordinates V with corresponding atoms to stdout in XYZ format.

Parameters:

• atoms (list) –

  List of atomic types

• V (array) –

  (N,3) matrix of atomic coordinates

• title (string(optional), default: '' ) –

  Title of molecule

• decimals (int(optional), default: 8 ) –

  number of decimals for the coordinates

Return

output : str Molecule in XYZ format

print_coordinates(atoms, V, title='')

Print coordinates V with corresponding atoms to stdout in XYZ format.

Parameters:

• atoms (list) –

  List of element types

• V (array) –

  (N,3) matrix of atomic coordinates

• title (string(optional), default: '' ) –

  Title of molecule

get_coordinates(filename, fmt, is_gzip=False, return_atoms_as_int=False)

Get coordinates from filename in format fmt. Supports XYZ and PDB.

Parameters:

• filename (string) –

  Filename to read

• fmt (string) –

  Format of filename. Either xyz or pdb.

Returns:

• atoms ( list ) –

  List of atomic types

• V ( array ) –

  (N,3) where N is number of atoms

get_coordinates_pdb(filename, is_gzip=False, return_atoms_as_int=False)

Get coordinates from the first chain in a pdb file and return a vectorset with all the coordinates.

Parameters:

• filename (string) –

  Filename to read

Returns:

• atoms ( list ) –

  List of atomic types

• V ( array ) –

  (N,3) where N is number of atoms

get_coordinates_xyz(filename, is_gzip=False, return_atoms_as_int=False)

Get coordinates from filename and return a vectorset with all the coordinates, in XYZ format.

Parameters:

• filename (string) –

  Filename to read

Returns:

• atoms ( list ) –

  List of atomic types

• V ( array ) –

  (N,3) where N is number of atoms