Source code for jscatter.lattice

# -*- coding: utf-8 -*-
# written by Ralf Biehl at the Forschungszentrum Jülich ,
# Jülich Center for Neutron Science 1 and Institute of Complex Systems 1
#    jscatter is a program to read, analyse and plot data
#    Copyright (C) 2015  Ralf Biehl
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
"""
---
Lattice objects describing a lattice of points.

Included are methods to select sublattices as parallelepiped, sphere or side of planes.

The small angle scattering is calculated by js.ff.cloudScattering.

The same method can be used to calculate the wide angle scattering with bragg peaks
using larger scattering vectors to get crystalline bragg peaks of nanoparticles.


**Examples**

A hollow sphere cut to a wedge.
::

 import jscatter as js
 import numpy as np
 grid= js.lattice.scLattice(1/2.,2*8,b=[0])
 grid.inSphere(6,b=1)
 grid.inSphere(4,b=0)
 grid.planeSide([1,1,1],b=0)
 grid.planeSide([1,-1,-1],b=0)
 grid.show()

 q=js.loglist(0.01,5,600)
 ffe=js.ff.cloudScattering(q,grid.points,relError=0.02,rms=0.1)
 p=js.grace()
 p.plot(ffe)

A cube decorated with spheres.
::

  import jscatter as js
  import numpy as np
  grid= js.lattice.scLattice(0.2,2*15,b=[0])
  v1=np.r_[4,0,0]
  v2=np.r_[0,4,0]
  v3=np.r_[0,0,4]
  grid.inParallelepiped(v1,v2,v3,b=1)
  grid.inSphere(1,center=[0,0,0],b=2)
  grid.inSphere(1,center=v1,b=3)
  grid.inSphere(1,center=v2,b=4)
  grid.inSphere(1,center=v3,b=5)
  grid.inSphere(1,center=v1+v2,b=6)
  grid.inSphere(1,center=v2+v3,b=7)
  grid.inSphere(1,center=v3+v1,b=8)
  grid.inSphere(1,center=v3+v2+v1,b=9)
  grid.show()

  q=js.loglist(0.01,5,600)
  ffe=js.ff.cloudScattering(q,grid.points,relError=0.02,rms=0.)
  p=js.grace()
  p.plot(ffe)



A comparison of sc, bcc and fcc nanoparticles (takes a while )
::

 import jscatter as js
 import numpy as np
 q=js.loglist(0.01,35,1500)
 q=np.r_[js.loglist(0.01,3,200),3:40:800j]
 unitcelllength=1.5
 N=8

 scgrid= js.lattice.scLattice(unitcelllength,N)
 sc=js.ff.cloudScattering(q,scgrid.points,relError=50,rms=0.05)
 bccgrid= js.lattice.bccLattice(unitcelllength,N)
 bcc=js.ff.cloudScattering(q,bccgrid.points,relError=50,rms=0.05)
 fccgrid= js.lattice.fccLattice(unitcelllength,N)
 fcc=js.ff.cloudScattering(q,fccgrid.points,relError=50,rms=0.05)

 p=js.grace(1.5,1)
 # smooth with Gaussian to include instrument resolution
 p.plot(sc.X,js.formel.smooth(sc,10, window='gaussian'),legend='sc')
 p.plot(bcc.X,js.formel.smooth(bcc,10, window='gaussian'),legend='bcc')
 p.plot(fcc.X,js.formel.smooth(fcc,10, window='gaussian'),legend='fcc')

 q=q=js.loglist(1,35,100)
 p.plot(q,(1-np.exp(-q*q*0.05**2))/scgrid.shape[0],li=1,sy=0,le='sc diffusive')
 p.plot(q,(1-np.exp(-q*q*0.05**2))/bccgrid.shape[0],li=2,sy=0,le='bcc diffusive')
 p.plot(q,(1-np.exp(-q*q*0.05**2))/fccgrid.shape[0],li=3,sy=0,le='fcc diffusive')

 p.title('Comparison sc, bcc, fcc lattice for a nano cube')
 p.yaxis(scale='l',label='I(Q)')
 p.xaxis(scale='l',label='Q / A\S-1')
 p.legend(x=0.03,y=0.001,charsize=1.5)
 p.text('cube formfactor',x=0.02,y=0.05,charsize=1.4)
 p.text('Bragg peaks',x=4,y=0.05,charsize=1.4)
 p.text('diffusive scattering',x=4,y=1e-6,charsize=1.4)

END
"""
from __future__ import division
from __future__ import print_function

import numpy as np
from numpy import linalg as la
from . import parallel
try:
    import matplotlib.pyplot as plt
    from mpl_toolkits.mplot3d import Axes3D
except:
    pass
try:
    from . import fscatter
    useFortran=True
except:
    useFortran = False

from . import formel

# tolerance for close to zero
_atol = 1e-12

[docs]class lattice(object): isLattice=True def __init__(self): """ Create an arbitrary lattice. Please use one of the subclasses below for creation. pseudorandom, rhombicLattice, bravaisLattice scLattice, bccLattice, fccLattice, diamondLattice, hexLattice, hcpLattice, sqLattice, hexLattice, lamLattice This base class defines methods valid for all subclasses. """ pass def __getitem__(self, item): return self.points[item] def __setitem__(self, item, value): if self[item].shape==np.shape(value): self.points[item] = value else: raise TypeError('Wrong shape of given value') @property def dimension(self): return self.points.shape[1]-1 @property def X(self): """X coordinates""" return self.points[:,0] @property def Y(self): """Y coordinates""" return self.points[:, 1] @property def Z(self): """Z coordinates""" return self.points[:, 2] @property def XYZ(self): """X,Y,Z coordinates array Nx3""" return self.points[:, :3] @property def b(self): """Scattering length""" return self.points[:, 3] @property def shape(self): return self.array.shape @property def type(self): """Returns type of the lattice""" return self._type @property def array(self): """Coordinates and scattering length as array""" return np.array(self.points)
[docs] def set_b(self,b): """ Set all initial points to given scattering length. """ self._points[:,3]=b
@property def points(self): """Points with scattering length >0 """ return self._points[ np.abs(self._points[:,3]) >_atol ]
[docs] def filter(self,funktion): """ Set lattice points scattering length according to a function. All points in the lattice are changed for which funktion returns value !=0 (tolerance 1e-12). Parameters ---------- funktion : function returning float Function to set lattice points scattering length. The function is applied with each i point coordinates (array) as input as .points[i,:3]. The return value is the corresponding scattering length. Examples -------- :: # To select points inside of a sphere with radius 5 around [1,1,1]: from numpy import linalg as la sc=js.sf.scLattice(0.9,10) sc.set_b(0) sc.filter(lambda xyz: 1 if la.norm(xyz-np.r_[1,1,1])<5 else 0) # sphere with increase from center from numpy import linalg as la sc=js.sf.scLattice(0.9,10) sc.set_b(0) sc.filter(lambda xyz: 2*(la.norm(xyz)) if la.norm(xyz)<5 else 0) fig=sc.show() """ # get float values v=np.array([funktion(point) for point in self._points[:,:3]]) # set for v !=0, dont change others choose= np.abs(v)>_atol self._points[choose,3]=v[choose]
[docs] def centerOfMass(self): """ CenterOf mass """ return self.points[:,:3].mean(axis=0)
[docs] def numberOfAtoms(self): """ Number of Atoms """ return self.points.shape[0]
[docs] def move(self,vector): """ Move all points by vector. Parameters ---------- vector : list of 3 float or array Vector to shift the points. """ self._points[:,:3]=self._points[:,:3]+np.array(vector)
[docs] def inParallelepiped(self, v1, v2, v3, corner=None, b=1, invert=False): """ Set scattering length for points in parallelepiped. Parameters ---------- corner : 3x float Corner of parallelepiped v1,v2,v3 : each 3x float Vectors from origin to 3 corners that define the parallelepiped. b: float Scattering length for selected points. invert : bool Invert selection Examples -------- :: import jscatter as js sc=js.sf.scLattice(0.2,10,b=[0]) sc.inParallelepiped([1,0,0],[0,1,0],[0,0,1],[0,0,0],1) sc.show() sc=js.sf.scLattice(0.1,30,b=[0]) sc.inParallelepiped([1,1,0],[0,1,1],[1,0,1],[-1,-1,-1],2) sc.show() """ if corner is None: corner = [0, 0, 0] a1=np.cross(v2,v3) b1=np.cross(v3,v1) c1 = np.cross(v1,v2) #vectors perpendicular to planes a1 = a1 / la.norm(a1) b1 = b1 / la.norm(b1) c1 = c1 / la.norm(c1) da = np.dot(self._points[:, :3] - corner, a1) da1=np.dot(np.array(v1) , a1) db = np.dot(self._points[:, :3] - corner, b1) db1= np.dot(np.array(v2) , b1) dc = np.dot(self._points[:, :3] - corner, c1) dc1= np.dot(np.array(v3) , c1) choose = (0<=da) & (da<=da1) & (0<=db) & (db<=db1) & (0<=dc) & (dc<=dc1) if invert: self._points[~choose,3] = b else: self._points[choose, 3] = b
[docs] def planeSide(self, vector, center=None, b=1, invert=False): """ Set scattering length for points on one side of a plane. Parameters ---------- center : 3x float, default [0,0,0] Point in plane. vector : list 3x float Vector perpendicular to plane. b: float Scattering length for selected points. invert : bool False choose points at origin side. True other side. Examples -------- :: sc=js.sf.scLattice(1,10,b=[0]) sc.planeSide([1,1,1],[3,3,3],1) sc.show() sc.planeSide([-1,-1,0],3) sc.show() """ if center is None: center = [0, 0, 0] v=np.array(vector) c=np.array(center) vv=(v ** 2).sum() ** 0.5 v=v/vv choose = np.dot(self._points[:, :3] - c, v) > 0 if invert: self._points[~choose,3] = b else: self._points[choose, 3] = b
[docs] def inSphere(self, R, center=None, b=1, invert=False): """ Set scattering length for points in sphere. Parameters ---------- center : 3 x float, default [0,0,0] Center of the sphere. R: float Radius of sphere around origin. b: float Scattering length for selected points. invert : bool True to invert selection. Examples -------- :: import jscatter as js sc=js.sf.scLattice(1,15,b=[0]) sc.inSphere(6,[2,2,2],b=1) sc.show() sc.inSphere(6,[-2,-2,-2],b=2) sc.show() sc=js.sf.scLattice(0.8,20,b=[0]) sc.inSphere(3,[2,2,2],b=1) sc.inSphere(3,[-2,-2,-2],b=1) sc.show() sc=js.sf.scLattice(0.8,20,b=[0]) sc.inSphere(3,[2,2,2],b=1) sc.inSphere(4,[0,0,0],b=2) sc.show() """ if center is None: center = [0, 0, 0] choose=la.norm(self._points[:,:3]-np.array(center),axis=1)<abs(R) if invert: self._points[~choose,3] = b else: self._points[choose, 3] = b
def _inEllipsoid(self,center,v,Rmajor,Rminor, b=1, invert=False): # only for prolate ellipsoid v=np.array(v) center=np.array(center) v=v/la.norm(v) c=abs(Rmajor**2-Rminor**2)**0.5 # 2 Foci P1=center-v*c P2=center+v*c a2=abs(Rmajor*2) print(P1,P2,c,a2) choose=(la.norm(self._points[:,:3]-P1,axis=1)+la.norm(self._points[:,:3]-P2,axis=1))<a2 if invert: self._points[~choose,3] = b else: self._points[choose, 3] = b
[docs] def show(self,R=None,cmap='rainbow'): """ Show the lattice in matplotlib with scattering length color coded. Parameters ---------- R : float,None Radius around origin to show. cmap : colormap Colormap. E.g. 'rainbow', 'winter','autumn','gray' Use js.mpl.showColors() for all possibilities. Returns ------- fig handle """ if R is None: points=self.points else: choose=la.norm(self.points[:,:3],axis=1)<R points=self.points[choose] if len(points) ==0: raise AttributeError('No points with b>0 to show') bmax = points[:, 3].max() bmin = points[:, 3].min() fig = plt.figure() ax = fig.add_subplot(111, projection='3d') ax.scatter(points[:,0],points[:,1],points[:,2],c=points[:,3],s=10,cmap=cmap,vmin=bmin, vmax=bmax,depthshade=False) try: for v in self.latticeVectors: ax.plot([0,v[0]],[0,v[1]],[0,v[2]],color='g') except: pass try: for v in self.unitCellAtomPositions: if (v**2).sum()==0: pass ax.plot([0,v[0]],[0,v[1]],[0,v[2]],color='b') except: pass ax.set_xlabel('x axis') ax.set_ylabel('y axis') ax.set_zlabel('z axis') #ax.set_aspect("equal") xyzmin=self.XYZ.min() xyzmax=self.XYZ.max() ax.set_xlim(xyzmin,xyzmax) ax.set_ylim(xyzmin,xyzmax) ax.set_zlim(xyzmin,xyzmax) plt.tight_layout() plt.show(block=False) return fig
def getReciprocalLattice(self, size=2): print('Only for rhombic lattices') return None def rotate2hkl(self,grid, h,k,l): print('Only for rhombic lattices') return None
[docs]class pseudoRandomLattice(lattice): def __init__(self, size, numberOfPoints, b=None, seed=None): """ Create a lattice with a pseudo random distribution of points. Allows to create 1D, 2D or 3D pseudo random latices. The Halton sequence is used with skipping the first seed elements of the Halton sequence. Parameters ---------- size :3x float Size of the lattice for each dimension relative to origin. numberOfPoints : int Number of points. b : float,array Scattering length of atoms. If array the sequence is repeated to fill N atoms. seed : None, int Seed for the Halton sequence by skipping the first seed elements of the sequence. If None an random integer between 10 and 1e6 is chosen. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.pseudoRandomLattice([5,5,5],3000) fig=grid.show() """ super(pseudoRandomLattice, self).__init__() self._makeLattice(size, numberOfPoints,b,seed) self._type='pseudorandom' def _makeLattice(self, size, N ,pb=None ,skip=None ): if pb is None: pb=1 dim=np.shape(size)[0] if skip is None: skip=np.random.randint(10,1000000) if useFortran: seq=fscatter.pseudorandom.halton_sequence(skip,skip+N-1,dim).T else: seq = parallel.haltonSequence(skip + N - 1, dim).T[skip-1:] seq=seq*np.array(size) if dim in [1,2]: seq=np.c_[seq,np.zeros((N,3-dim))] self._points=np.c_[seq,np.tile(pb,N)[:N]]
# noinspection PyMissingConstructor
[docs]class rhombicLattice(lattice): isRhombic=True def __init__(self, latticeVectors, size, unitCellAtoms=None, b=None): """ Create a rhombic lattice with specified unit cell atoms. Allows to create 1D, 2D or 3D latices by using 1, 2 or 3 latticeVectors. Parameters ---------- latticeVectors : list of array 3x1 Lattice vectors defining the translation of the unit cell along its principal axes. size :3x integer or integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. unitCellAtoms : list of 3x1 array, None=[0,0,0] Position vectors of atoms in the unit cell in relative units of the lattice vectors [0<x<1]. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array .unitCellVolume V = a1*a2 x a3 with latticeVectors a1, a2, a3; if existing. Examples -------- :: import jscatter as js import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D # cubic lattice with diatomic base grid=js.sf.rhombicLattice([[1,0,0],[0,1,0],[0,0,1]],[3,3,3],[[-0.1,-0.1,-0.1],[0.1,0.1,0.1]],[1,2]) grid.show(1.5) """ if len(latticeVectors) != len(size): raise TypeError('size and latticeVectors not compatible. Check dimension!') if unitCellAtoms is None: unitCellAtoms = [np.r_[0, 0, 0]] size=np.trunc(size) if b is None: b=[1]*len(unitCellAtoms) self.unitCellAtoms_b=b # calc reciprocal vectors if len(latticeVectors)==3: V=np.dot(latticeVectors[0],np.cross(latticeVectors[1],latticeVectors[2])) self.unitCellVolume = V self.reciprocalVectors = [] self.reciprocalVectors.append(2 * np.pi / V * np.cross(latticeVectors[1], latticeVectors[2])) self.reciprocalVectors.append(2 * np.pi / V * np.cross(latticeVectors[2], latticeVectors[0])) self.reciprocalVectors.append(2 * np.pi / V * np.cross(latticeVectors[0], latticeVectors[1])) elif len(latticeVectors)==2: R=formel.rotationMatrix(np.r_[0,0,1],np.pi/2) self.reciprocalVectors = [] v0=np.dot(R, latticeVectors[0]) v1 = np.dot(R, latticeVectors[1]) self.unitCellVolume = np.dot(v0,v1) self.reciprocalVectors.append(2 * np.pi * v1/np.dot(latticeVectors[0],v1)) self.reciprocalVectors.append(2 * np.pi * v0/np.dot(latticeVectors[1],v0)) elif len(latticeVectors)==1: R = formel.rotationMatrix(np.r_[0, 0, 1], np.pi / 2) v0 = np.dot(R, latticeVectors[0]) self.unitCellVolume = la.norm(v0) self.reciprocalVectors = [] self.reciprocalVectors.append(2 * np.pi *v0/la.norm(v0)**2) self.latticeVectors=latticeVectors self.size=size self._makeLattice( self.latticeVectors, size, unitCellAtoms, self.unitCellAtoms_b) self._type='rhombic' def _makeLattice(self, latticeVectors, size, unitCellAtoms=None,pb=None): abc=latticeVectors[0]*np.r_[-size[0]:size[0]+1][:,None] if len(size)>1: abc = abc+(latticeVectors[1]*np.r_[-size[1]:size[1]+1][:,None])[:,None] if len(size) > 2: abc = abc + (latticeVectors[2]*np.r_[-size[2]:size[2]+1][:,None,None])[:,None,None] abc=abc.reshape(-1,3) abc=np.c_[(abc,np.zeros(abc.shape[0]))] uCA=np.einsum('il,ji',latticeVectors,unitCellAtoms) self._points=np.vstack([abc + np.r_[ev,b] for ev,b in zip(uCA,pb)]) self.unitCellAtoms=unitCellAtoms @property def unitCellAtomPositions(self): """ Absolute positions of unit cell atoms. """ return np.einsum('il,ji',self.latticeVectors,self.unitCellAtoms)
[docs] def getReciprocalLattice(self,size=2): """ Reciprocal lattice of given size with peak scattering intensity. Parameters ---------- size : 3x int or int, default 2 Number of reciprocal lattice points in each direction (+- direction). Returns ------- Array [N x 4] with reciprocal lattice vectors [:,:3] corresponding structure factor fhkl**2>0 [:, 3] """ if isinstance(size,int): size=[size]*3 size=np.trunc(size) # create lattice bbb = self.reciprocalVectors[0] * np.r_[-size[0]:size[0] + 1][:, None] hkl = np.r_[1,0,0] * np.r_[-size[0]:size[0] + 1][:, None] if len(self.reciprocalVectors)>1: bbb = bbb + (self.reciprocalVectors[1] * np.r_[-size[1]:size[1] + 1][:, None])[:, None] hkl = hkl + (np.r_[0,1,0] * np.r_[-size[1]:size[1] + 1][:, None])[:, None] if len(self.reciprocalVectors) > 2: bbb = bbb + (self.reciprocalVectors[2] * np.r_[-size[2]:size[2] + 1][:, None, None])[:, None, None] hkl = hkl + (np.r_[0,0,1] * np.r_[-size[2]:size[2] + 1][:, None, None])[:, None, None] bbb = bbb.reshape(-1, 3) hkl = hkl.reshape(-1, 3) # calc structure factor f2hkl=self._f2hkl(hkl) # selection rule choose=(f2hkl > 1e-10*f2hkl.max() ) return np.c_[bbb[choose],f2hkl[choose]]
[docs] def getRadialReciprocalLattice(self,size,includeZero=False): """ Get radial distribution of Bragg peaks with structure factor and multiplicity. Parameters ---------- size : int Size of the lattice as maximum included Miller indices. includeZero : bool Include q=0 peak Returns ------- 3x list of [unique q values, structure factor fhkl(q)**2, multiplicity mhkl(q)] """ qxyzb=self.getReciprocalLattice(size) qr=la.norm(qxyzb[:,:3],axis=1) f2hkl=qxyzb[:,3] tol=1e7 qrunique,qrindex,qrcount=np.unique(np.floor(qr*tol)/tol,return_index=True,return_inverse=False,return_counts=True) # q values of unique peaks, scattering strength f2hkl, multiplicity as number of unique peaks from 3D count if includeZero: return qrunique,f2hkl[qrindex],qrcount else: return qrunique[1:], f2hkl[qrindex][1:], qrcount[1:]
def _f2hkl(self,hkl): """ Structure factor f**2_hkl which includes the extinction rules. """ pb=np.array(self.unitCellAtoms_b)[:,None] hxkylz=np.einsum('ij,lj',self.unitCellAtoms,hkl) fhkl=(pb*np.exp(2j*np.pi*hxkylz)).sum(axis=0) return (fhkl*fhkl.conj()).real
[docs] def rotate2hkl(self,grid, h,k,l): """ Rotate grid that the grid center lies in hkl direction and tangential to hkl direction. Parameters ---------- grid : array Nx3 Grid points h,k,l : integer, float Miller indices indicating the direction where to rotate to. Returns ------- grid points array 4xN Examples -------- :: import jscatter as js import numpy as np R=8 N=10 qxy=np.mgrid[-R:R:N*1j, -R:R:N*1j].reshape(2,-1).T qxyz=np.c_[qxy,np.zeros(N**2)] fccgrid = js.lattice.fccLattice(2.1, 1) xyz=fccgrid.rotate2hkl(qxyz,1,1,1) p=js.mpl.scatter3d(xyz[:,0],xyz[:,1],xyz[:,2]) p.axes[0].scatter(fccgrid.X,fccgrid.Y,fccgrid.Z) """ # hkl direction vhkl=h*self.latticeVectors[0]+k*self.latticeVectors[1]+l*self.latticeVectors[2] # vector perpendicular to grid plane center=grid.mean(axis=0) centerdistance=((grid-center)**2).sum(axis=1)**0.5 isort=np.argsort(centerdistance) # first vector in grid close to center, then next with cross >0 v1=grid[isort[0]]-grid[isort[1]] i=2 while True: v2=grid[isort[0]]-grid[isort[i]] v3=np.cross(v1,v2) # test if >0 then it is perpendicular to plane if la.norm(v3)>0: break else:i+=1 rotvector=np.cross(vhkl,v3)/la.norm(v3)/la.norm(vhkl) angle=np.arccos(np.clip(np.dot(vhkl/la.norm(vhkl), v3/la.norm(v3)), -1.0, 1.0)) R=formel.rotationMatrix(rotvector,angle) Rgrid=np.einsum('ij,kj->ki',R,grid) return Rgrid
[docs]class bravaisLattice(rhombicLattice): def __init__(self, latticeVectors, size,b=None): """ Create a Bravais lattice. Lattice with one atom in the unit cell. See rhombicLattice for methods and attributes. Parameters ---------- latticeVectors : list of array 1x3 Lattice vectors defining the translation of the unit cell along its principal axes. size :3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array """ rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms=[np.r_[0,0,0]], b=b) self._type = 'bravais'
[docs]class scLattice(bravaisLattice): def __init__(self, abc, size, b=None): """ Simple Cubic lattice. See rhombicLattice for methods. Parameters ---------- abc : float Point distance. size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D grid=js.sf.bccLattice(1.2,1) grid.show(2) """ latticeVectors = [abc * np.r_[1., 0., 0.], abc * np.r_[0., 1., 0.], abc * np.r_[0., 0., 1.]] if isinstance(size,(int,float)): size = [size]*3 bravaisLattice.__init__(self, latticeVectors, size,b=b) self._type = 'sc'
[docs]class bccLattice(rhombicLattice): def __init__(self, abc, size,b=None): """ Body centered cubic lattice. See rhombicLattice for methods. Parameters ---------- abc : float Point distance. size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.bccLattice(1.2,1) grid.show(2) """ unitCellAtoms = [np.r_[0, 0, 0], np.r_[0.5, 0.5, 0.5]] latticeVectors = [abc * np.r_[1., 0., 0.], abc * np.r_[0., 1., 0.], abc * np.r_[0., 0., 1.]] if isinstance(size,(int,float)): size = [size]*3 rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms,b=b) self._type = 'bcc'
[docs]class fccLattice(rhombicLattice): def __init__(self, abc, size,b=None): """ Face centered cubic lattice. See rhombicLattice for methods. Parameters ---------- abc : float Point distance. size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D grid=js.sf.fccLattice(1.2,1) grid.show(2) """ unitCellAtoms = [np.r_[0, 0, 0], np.r_[0, 0.5, 0.5], np.r_[0.5, 0, 0.5], np.r_[0.5, 0.5, 0]] latticeVectors = [abc *np.r_[1., 0., 0.], abc *np.r_[0., 1., 0.], abc *np.r_[0., 0., 1.]] if isinstance(size,(int,float)): size = [size]*3 rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms,b=b) self._type = 'fcc'
[docs]class diamondLattice(rhombicLattice): def __init__(self, abc, size, b=None): """ Diamond cubic lattice with 8 atoms in unit cell. See rhombicLattice for methods. Parameters ---------- abc : float Point distance. size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.diamondLattice(1.2,1) grid.show(2) """ unitCellAtoms = [np.r_[0, 0, 0], np.r_[0.5, 0.5,0], np.r_[0, 0.5, 0.5], np.r_[0.5, 0, 0.5], np.r_[1 / 4., 1 / 4., 1 / 4.], np.r_[3 / 4., 3 / 4., 1 / 4.], np.r_[1 / 4., 3 / 4., 3 / 4.], np.r_[3 / 4., 1 / 4., 3 / 4.]] latticeVectors = [abc *np.r_[1., 0., 0.], abc *np.r_[0., 1., 0.], abc *np.r_[0., 0., 1.]] if isinstance(size,(int,float)): size = [size]*3 rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms,b=b) self._type = 'diamond'
class hexLattice(rhombicLattice): def __init__(self, ab,c, size,b=None): """ Hexagonal lattice. See rhombicLattice for methods. Parameters ---------- ab,c : float Point distance. ab is distance in hexagonal plane, c perpendicular. For c/a = (8/3)**0.5 the hcp structure size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D grid=js.sf.hexLattice(1.,2,[2,2,2]) grid.show(2) """ latticeVectors = [np.r_[ab, 0., 0.], np.r_[0.5*ab, 3**0.5/2*ab, 0.], np.r_[0., 0., c]] unitCellAtoms = [ np.r_[0, 0, 0] ] if isinstance(size,(int,float)): size = [size]*3 rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms,b=b) self._type = 'hex'
[docs]class hcpLattice(rhombicLattice): def __init__(self, ab, size,b=None): """ Hexagonal closed packed lattice. See rhombicLattice for methods. Parameters ---------- ab : float Point distance. ab is distance in hexagonal plane, c = ab* (8/3)**0.5 size : 3x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D grid=js.sf.hcpLattice(1.2,[3,3,1]) grid.show(2) """ c = ab* (8/3.)**0.5 latticeVectors = [np.r_[ab, 0., 0.], np.r_[0.5*ab, 3**0.5/2*ab, 0.], np.r_[0., 0., c]] unitCellAtoms = [ np.r_[0, 0, 0], np.r_[1/3. , 1/3.,0.5 ]] if isinstance(size,(int,float)): size = [size]*3 rhombicLattice.__init__(self, latticeVectors, size, unitCellAtoms,b=b) self._type = 'hcp'
class sqLattice(bravaisLattice): def __init__(self, ab, size, b=None): """ Simple 2D square lattice. See rhombicLattice for methods. Parameters ---------- ab : float Point distance. size : 2x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.sqLattice(1.2,1) grid.show(2) """ latticeVectors = [ab * np.r_[1., 0., 0.], ab * np.r_[0., 1., 0.]] if isinstance(size,(int,float)): size = [size]*2 bravaisLattice.__init__(self, latticeVectors, size, b=b) self._type = 'sq'
[docs]class hexLattice(bravaisLattice): def __init__(self, ab, size, b=None): """ Simple 2D hexagonal lattice. See rhombicLattice for methods. Parameters ---------- ab : float Point distance. size : 2x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.hexLattice(1.2,1) grid.show(2) """ latticeVectors = [np.r_[ab, 0., 0.], np.r_[0.5*ab, 3**0.5/2*ab, 0.]] if isinstance(size,(int,float)): size = [size]*2 bravaisLattice.__init__(self, latticeVectors, size,b=b) self._type = 'hex'
class lamLattice(bravaisLattice): def __init__(self, a, size, b=None): """ 1D lamellar lattice. See rhombicLattice for methods. Parameters ---------- a : float Point distance. size : 2x integer, integer A list of integers describing the size in direction of the respective latticeVectors. Size is symmetric around zero in interval [-i,..,i] with length 2i+1. If one integer is given it is used for all 3 dimensions. b : list of float Corresponding scattering length of atoms in the unit cell. Returns ------- lattice object .array grid points as numpy array Examples -------- :: import jscatter as js grid=js.sf.lamLattice(1.2,1) grid.show(2) """ latticeVectors = [np.r_[a, 0., 0.]] if isinstance(size,(int,float)): size = [size]*1 bravaisLattice.__init__(self, latticeVectors, size,b=b) self._type = 'lam'