suspendtools/field.py

1081 lines
50 KiB
Python

import numpy as np
class Field3d:
def __init__(self,data,origin,spacing,deep=False):
assert len(origin)==3, "'origin' must be of length 3"
assert len(spacing)==3, "'spacing' must be of length 3"
assert isinstance(data,np.ndarray), "'data' must be numpy.ndarray."
if deep:
self.data = data.copy()
else:
self.data = data
self.origin = tuple([float(x) for x in origin])
self.spacing = tuple([float(x) for x in spacing])
self.eps_collapse = 1e-8
self._dim = None
return
def __str__(self):
str = 'Field3d with\n'
str+= ' dimension: {}, {}, {}\n'.format(*self.dim())
str+= ' origin: {:G}, {:G}, {:G}\n'.format(*self.origin)
str+= ' spacing: {:G}, {:G}, {:G}\n'.format(*self.spacing)
str+= ' datatype: {}'.format(self.dtype())
return str
def __add__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
return Field3d(self.data+other.data,self.origin,self.spacing)
else:
return Field3d(self.data+other,self.origin,self.spacing)
def __sub__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
return Field3d(self.data-other.data,self.origin,self.spacing)
else:
return Field3d(self.data-other,self.origin,self.spacing)
def __mul__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
return Field3d(self.data*other.data,self.origin,self.spacing)
else:
return Field3d(self.data*other,self.origin,self.spacing)
def __truediv__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
return Field3d(self.data/other.data,self.origin,self.spacing)
else:
return Field3d(self.data/other,self.origin,self.spacing)
def __radd__(self,other):
return Field3d(other+self.data,self.origin,self.spacing)
def __rmul__(self,other):
return Field3d(other*self.data,self.origin,self.spacing)
def __pow__(self,other):
return Field3d(self.data**other,self.origin,self.spacing)
def __iadd__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
self.data += other.data
else:
self.data += other
return self
def __isub__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
self.data -= other.data
else:
self.data -= other
return self
def __imul__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
self.data *= other.data
else:
self.data *= other
return self
def __itruediv__(self,other):
if isinstance(other,Field3d):
assert self.has_same_grid(other), "Grid mismatch."
self.data /= other.data
else:
self.data /= other
return self
# TBD: this should return another Field3d object
# def __getitem__(self,val):
# assert isinstance(val,tuple) and len(val)==3, "Field3d must be indexed by [ii,jj,kk]."
# sl = []
# for x in val:
# if isinstance(x,int):
# lo,hi = x,x+1
# hi = hi if hi!=0 else None
# sl.append(slice(lo,hi))
# elif isinstance(x,slice):
# sl.append(x)
# else:
# raise TypeError("Trajectories can only be sliced by slice objects or integers.")
# return self.data[sl[0],sl[1],sl[2]]
@classmethod
def from_chunk(cls,chunk,gridg):
'''Initialize Field3d from chunk data and global grid.'''
xg,yg,zg = gridg
ib,jb,kb = chunk['ibeg']-1, chunk['jbeg']-1, chunk['kbeg']-1
dx,dy,dz = xg[1]-xg[0], yg[1]-yg[0], zg[1]-zg[0]
xo,yo,zo = xg[ib]-chunk['ighost']*dx, yg[jb]-chunk['ighost']*dy, zg[kb]-chunk['ighost']*dz
nx,ny,nz = chunk['data'].shape
assert (chunk['nxl']+2*chunk['ighost'])==nx, "Invalid chunk data: nxl != chunk['data'].shape[0]"
assert (chunk['nyl']+2*chunk['ighost'])==ny, "Invalid chunk data: nyl != chunk['data'].shape[1]"
assert (chunk['nzl']+2*chunk['ighost'])==nz, "Invalid chunk data: nzl != chunk['data'].shape[2]"
return cls(chunk['data'],origin=(xo,yo,zo),spacing=(dx,dy,dz))
@classmethod
def from_file(cls,file,name='Field3d'):
import h5py
is_open = isinstance(file,(h5py.File,h5py.Group))
f = file if is_open else h5py.File(file,'r')
g = f[name]
origin = tuple(g['origin'])
spacing = tuple(g['spacing'])
data = g['data'][:]
if not is_open: f.close()
return cls(data,origin,spacing)
@classmethod
def allocate(cls,dim,origin,spacing,fill=None,dtype=np.float64):
'''Allocates an empty field, or a field filled with 'fill'.'''
assert isinstance(dim,(tuple,list,np.ndarray)) and len(dim)==3,\
"'dim' must be a tuple/list of length 3."
assert isinstance(origin,(tuple,list,np.ndarray)) and len(origin)==3,\
"'origin' must be a tuple/list of length 3."
assert isinstance(spacing,(tuple,list,np.ndarray)) and len(spacing)==3,\
"'spacing' must be a tuple/list of length 3."
if fill is None:
data = np.empty(dim,dtype=dtype)
else:
data = np.full(dim,fill,dtype=dtype)
return cls(data,origin,spacing)
@classmethod
def pseudo_field(cls,dim,origin,spacing):
'''Creates a Field3d instance without allocating any memory.'''
assert isinstance(dim,(tuple,list,np.ndarray)) and len(dim)==3,\
"'dim' must be a tuple/list of length 3."
assert isinstance(origin,(tuple,list,np.ndarray)) and len(origin)==3,\
"'origin' must be a tuple/list of length 3."
assert isinstance(spacing,(tuple,list,np.ndarray)) and len(spacing)==3,\
"'spacing' must be a tuple/list of length 3."
data = np.empty((0,0,0))
r = cls(data,origin,spacing)
r._dim = dim
return r
def save(self,file,name='Field3d',truncate=False):
import h5py
is_open = isinstance(file,(h5py.File,h5py.Group))
flag = 'w' if truncate else 'a'
f = file if is_open else h5py.File(file,flag)
g = f.create_group(name)
g.create_dataset('origin',data=self.origin)
g.create_dataset('spacing',data=self.spacing)
g.create_dataset('data',data=self.data)
if not is_open: f.close()
return
def copy(self):
return Field3d(self.data.copy(),self.origin,self.spacing)
def pseudo_copy(self):
return self.pseudo_field(self.dim(),self.origin,self.spacing)
def insert_subfield(self,subfield):
assert all([abs(subfield.spacing[ii]-self.spacing[ii])<self.eps_collapse
for ii in range(3)]), "spacing differs. Got {}, have {}".format(subfield.spacing,self.spacing)
assert all([self.distance_to_nearest_gridpoint(subfield.origin[ii],axis=ii)<self.eps_collapse
for ii in range(3)]), "subfield has shifted origin."
assert all(self.is_within_bounds(subfield.origin,axis=None)), "subfield origin is out-of-bounds."
assert all(self.is_within_bounds(subfield.endpoint(),axis=None)), "subfield endpoint is out-of-bounds."
#ib,jb,kb = [int(round((subfield.origin[ii]-self.origin[ii])/self.spacing[ii])) for ii in range(3)]
ib,jb,kb = self.nearest_gridpoint(subfield.origin,axis=None)
nx,ny,nz = subfield.dim()
self.data[ib:ib+nx,jb:jb+ny,kb:kb+nz] = subfield.data[:,:,:]
return
def extract_subfield(self,idx_origin,dim,stride=(1,1,1),deep=False,strict_bounds=True):
if strict_bounds:
assert all(idx_origin[ii]>=0 and idx_origin[ii]<self.dim(axis=ii) for ii in range(3)),\
"'origin' is out-of-bounds."
assert all(idx_origin[ii]+stride[ii]*(dim[ii]-1)<self.dim(axis=ii) for ii in range(3)),\
"endpoint is out-of-bounds."
else:
for ii in range(3):
if idx_origin[ii]<0:
dim[ii] += idx_origin[ii]
idx_origin[ii] = 0
if idx_origin[ii]+stride[ii]*(dim[ii]-1)>=self.dim(axis=ii):
dim[ii] = (self.dim(axis=ii)-idx_origin[ii])//stride[ii]
if dim[ii]<=0:
return None
sl = tuple(slice(idx_origin[ii],
idx_origin[ii]+stride[ii]*dim[ii],
stride[ii]) for ii in range(3))
origin = self.coordinate(idx_origin)
spacing = tuple(self.spacing[ii]*stride[ii] for ii in range(3))
data = self.data[sl]
return Field3d(data,origin,spacing,deep=deep)
def clip(self,position,axis,invert=False,deep=False,is_relative=False):
'''Extracts a subfield by clipping with a plane with normal pointing
direction specified by 'axis'.'''
if is_relative:
coord = self.origin[axis] + coord*self.dim(axis=axis)*self.spacing[axis]
idx_clip = self.nearest_gridpoint(coord,axis=axis,lower=True)
sl = 3*[slice(None)]
origin_ = self.origin
spacing_ = self.spacing
if invert:
sl[axis] = slice(idx_clip+1,None)
origin_[axis] = self.origin[axis]+idx_clip*self.spacing[axis]
else:
sl[axis] = slice(0,idx_clip+1)
data_ = self.data[tuple(sl)]
return Field3d(data_,origin_,spacing_,deep=deep)
def clip_box(self,bounds,deep=False,is_relative=False):
'''Extracts a subfield by clipping with a box.'''
if is_relative:
bounds = tuple(self.origin[ii//2] + bounds[ii]*self.dim(ii//2)*self.spacing[ii//2] for ii in range(6))
idx_lo = self.nearest_gridpoint((bounds[0],bounds[2],bounds[4]),lower=True)
idx_hi = self.nearest_gridpoint((bounds[1],bounds[3],bounds[5]),lower=True)
idx_lo = tuple(0 if idx_lo[axis]<0 else idx_lo[axis] for axis in range(3))
idx_hi = tuple(0 if idx_hi[axis]<0 else idx_hi[axis] for axis in range(3))
sl_ = tuple([slice(idx_lo[0],idx_hi[0]+1),
slice(idx_lo[1],idx_hi[1]+1),
slice(idx_lo[2],idx_hi[2]+1)])
origin_ = tuple(self.origin[axis]+idx_lo[axis]*self.spacing[axis] for axis in range(3))
spacing_ = self.spacing
data_ = self.data[sl_]
return Field3d(data_,origin_,spacing_,deep=deep)
def threshold(self,val,invert=False):
'''Returns a binary array indicating which grid points are above,
or in case of invert=True below, a given threshold.'''
if invert:
return self.data<val
else:
return self.data>=val
def coordinate(self,idx,axis=None):
if axis is None:
assert len(idx)==3, "If 'axis' is None, 'idx' must be a tuple/list of length 3."
return tuple(self.coordinate(idx[ii],axis=ii) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
assert idx<self.dim(axis=axis), "'idx' is out-of-bounds."
return self.origin[axis]+idx*self.spacing[axis]
def grid(self,axis=None):
if axis is None:
return tuple(self.grid(axis=ii) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
return self.origin[axis]+np.arange(0,self.dim(axis=axis))*self.spacing[axis]
def x(self): return self.grid(axis=0)
def y(self): return self.grid(axis=1)
def z(self): return self.grid(axis=2)
def nearest_gridpoint(self,coord,axis=None,lower=False):
if axis is None:
assert len(coord)==3, "If 'axis' is None, 'coord' must be a tuple/list of length 3."
return tuple(self.nearest_gridpoint(coord[ii],axis=ii,lower=lower) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
if lower:
return np.floor((coord+self.eps_collapse-self.origin[axis])/self.spacing[axis]).astype('int')
else:
return np.round((coord-self.origin[axis])/self.spacing[axis]).astype('int')
def distance_to_nearest_gridpoint(self,coord,axis=None,lower=False):
if axis is None:
assert len(coord)==3, "If 'axis' is None, 'coord' must be a tuple/list of length 3."
return tuple(self.distance_to_nearest_gridpoint(coord[ii],axis=ii,lower=lower) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
val = np.remainder(coord+self.eps_collapse-self.origin[axis],self.spacing[axis])-self.eps_collapse
if not lower and val>0.5*self.spacing[axis]:
val = self.spacing[axis]-val
return val
def is_within_bounds(self,coord,axis=None):
if axis is None:
assert len(coord)==3, "If 'axis' is None, 'coord' must be a tuple/list of length 3."
return tuple(self.is_within_bounds(coord[ii],axis=ii) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
idx_nearest = self.nearest_gridpoint(coord,axis=axis)
if idx_nearest>0 and idx_nearest<self.dim(axis=axis)-1:
return True
dist_nearest = self.distance_to_nearest_gridpoint(coord,axis=axis)
if (idx_nearest==0 or idx_nearest==self.dim(axis=axis)-1) and abs(dist_nearest)<self.eps_collapse:
return True
else:
return False
def has_same_grid(self,other):
if not self.has_same_origin(other): return False
if not self.has_same_spacing(other): return False
if not self.has_same_origin(other): return False
return True
def has_same_origin(self,other,axis=None):
if axis is None:
return all([self.has_same_origin(other,axis=ii) for ii in range(3)])
origin = other.origin if isinstance(other,Field3d) else other
return abs(origin[axis]-self.origin[axis])<self.eps_collapse
def has_same_spacing(self,other,axis=None):
if axis is None:
return all([self.has_same_spacing(other,axis=ii) for ii in range(3)])
spacing = other.spacing if isinstance(other,Field3d) else other
return abs(spacing[axis]-self.spacing[axis])<self.eps_collapse
def has_same_dim(self,other,axis=None):
if axis is None:
return all([self.has_same_dim(other,axis=ii) for ii in range(3)])
dim = other.dim(axis=axis) if isinstance(other,Field3d) else other
return dim==self.dim(axis=axis)
def dim(self,axis=None):
if axis is None:
return tuple(self.dim(axis=ii) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
if self._dim is not None:
return self._dim[axis]
else:
return self.data.shape[axis]
def endpoint(self,axis=None):
if axis is None:
return tuple(self.endpoint(axis=ii) for ii in range(3))
assert axis<3, "'axis' must be one of 0,1,2."
return self.origin[axis]+(self.dim(axis=axis)-1)*self.spacing[axis]
def dtype(self):
return self.data.dtype
def convert_dtype(self,dtype):
self.data = self.data.astype(dtype,copy=False)
return
def derivative(self,axis,only_keep_interior=False,shift_origin='before'):
'''Computes derivative wrt to direction 'axis' with 2nd order finite differences
centered between the origin grid points'''
from scipy import ndimage
assert axis<3, "'axis' must be one of 0,1,2."
origin = list(self.origin)
assert shift_origin in ('before','after'), "'shift_origin' must be one of {'before','after'}."
if shift_origin=='left':
corr_orig = 0
origin[axis] -= 0.5*self.spacing[axis]
else:
corr_orig = -1
origin[axis] += 0.5*self.spacing[axis]
data = ndimage.correlate1d(self.data,np.array([-1.,1.])/self.spacing[axis],axis=axis,
mode='constant',cval=np.nan,origin=corr_orig)
if only_keep_interior:
sl = 3*[slice(None)]
if shift_origin=='before':
sl[axis] = slice(-1,None)
origin[axis] += self.spacing[axis]
else:
sl[axis] = slice(0,-1)
data = data[tuple(sl)]
return Field3d(data,origin,self.spacing)
def gradient(self,axis,preserve_origin=False,only_keep_interior=False,add_border='before'):
return [self.derivative(axis,preserve_origin=preserve_origin,
only_keep_interior=only_keep_interior,add_border=add_border) for axis in range(0,3)]
def laplacian(self,only_keep_interior=False):
'''Computes the Laplacian of a field.'''
from scipy import ndimage
data = ndimage.correlate1d(self.data,np.array([1.,-2.,1.])/self.spacing[0]**2,axis=0,mode='constant',cval=np.nan,origin=0)
data += ndimage.correlate1d(self.data,np.array([1.,-2.,1.])/self.spacing[1]**2,axis=1,mode='constant',cval=np.nan,origin=0)
data += ndimage.correlate1d(self.data,np.array([1.,-2.,1.])/self.spacing[2]**2,axis=2,mode='constant',cval=np.nan,origin=0)
origin = list(self.origin)
if only_keep_interior:
data = data[1:-1,1:-1,1:-1]
for axis in range(3):
origin[axis] = origin[axis]+self.spacing[axis]
return Field3d(data,origin,self.spacing)
def integral(self,integrate_axis,average=False,ignore_nan=False,return_weights=False,ufunc=None):
'''Computes the integral or average along a given axis applying the
function 'ufunc' to each node.'''
assert isinstance(integrate_axis,(list,tuple,np.ndarray)) and len(integrate_axis)==3,\
"'integrate_axis' must be a tuple/list of length 3."
assert all([isinstance(integrate_axis[ii],(bool,int)) for ii in range(3)]),\
"'integrate_axis' requires bool values."
assert any(integrate_axis), "'integrate_axis' must contain at least one True."
axes = []
weight = 1.0
for axis in range(3):
if integrate_axis[axis]:
axes.append(axis)
if average:
weight *= self.dim(axis=axis)
else:
weight *= self.spacing[axis]
axes = tuple(axes)
if ignore_nan:
if average:
weight = np.sum(~np.isnan(self.data),axis=axes,keepdims=True)
func_sum = np.nansum
else:
func_sum = np.sum
if ufunc is None:
out = func_sum(self.data,axis=axes,keepdims=True)
else:
assert isinstance(ufunc,np.ufunc), "'ufunc' needs to be a numpy ufunc. "\
"Check out https://numpy.org/doc/stable/reference/ufuncs.html for reference."
assert ufunc.nin==1, "Only ufunc with single input argument are supported for now."
out = func_sum(ufunc(self.data),axis=axes,keepdims=True)
if return_weights:
return (out,weight)
else:
return out/weight
def gaussian_filter(self,sigma,truncate=4.0,only_keep_interior=False):
'''Applies a gaussian filter: sigma is standard deviation for Gaussian kernel for each axis.'''
from scipy import ndimage
assert isinstance(sigma,(tuple,list,np.ndarray)) and len(sigma)==3,\
"'sigma' must be a tuple/list of length 3"
# Convert sigma from simulation length scales to grid points as required by ndimage
sigma_img = tuple(sigma[ii]/self.spacing[ii] for ii in range(3))
data = ndimage.gaussian_filter(self.data,sigma_img,truncate=truncate,mode='constant',cval=np.nan)
origin = list(self.origin)
if only_keep_interior:
r = self.gaussian_filter_radius(sigma,truncate=truncate)
data = data[r[0]:-r[0],r[1]:-r[1],r[2]:-r[2]]
for axis in range(3):
origin[axis] = origin[axis]+r[axis]*self.spacing[axis]
return Field3d(data,origin,self.spacing)
def gaussian_filter_radius(self,sigma,truncate=4.0):
'''Radius of Gaussian filter. Stencil width is 2*radius+1.'''
assert isinstance(sigma,(tuple,list,np.ndarray)) and len(sigma)==3,\
"'sigma' must be a tuple/list of length 3"
# Convert sigma from simulation length scales to grid points as required by ndimage
sigma_img = tuple(sigma[ii]/self.spacing[ii] for ii in range(3))
radius = []
for ii in range(3):
radius.append(int(truncate*sigma_img[ii]+0.5))
return tuple(radius)
def shift_origin(self,rel_shift,only_keep_interior=False):
'''Shifts the origin of a field by multiple of spacing.'''
from scipy import ndimage
assert isinstance(rel_shift,(tuple,list,np.ndarray)) and len(rel_shift)==3,\
"'shift' must be tuple/list with length 3."
assert all([rel_shift[ii]>=-1.0-self.eps_collapse and rel_shift[ii]<=1.0+self.eps_collapse for ii in range(3)]),\
"'shift' must be in (-1.0,1.0). {}".format(rel_shift)
data = self.data.copy()
origin = list(self.origin)
sl = 3*[slice(None)]
for axis in range(3):
if abs(rel_shift[axis])<self.eps_collapse:
continue
elif rel_shift[axis]>0:
w = rel_shift[axis] if rel_shift[axis]<=1.0 else 1.0
weights = (1.0-w,w)
data = ndimage.correlate1d(data,weights,axis=axis,mode='constant',cval=np.nan,origin=-1)
origin[axis] += w*self.spacing[axis]
if only_keep_interior:
sl[axis] = slice(0,-1)
else:
w = rel_shift[axis] if rel_shift[axis]>=-1.0 else -1.0
weights = (-w,1.0+w)
data = ndimage.correlate1d(data,weights,axis=axis,mode='constant',cval=np.nan,origin=0)
origin[axis] += w*self.spacing[axis]
if only_keep_interior:
sl[axis] = slice(1,None)
origin[axis] += self.spacing[axis]
if only_keep_interior:
data = data[sl]
return Field3d(data,origin,self.spacing)
def relative_shift(self,field):
'''Compute the relative shift (in terms of spacing) to shift self onto field.'''
assert self.has_same_spacing(field), "spacing differs."
rel_shift = [0.0,0.0,0.0]
for axis in range(3):
dist = field.origin[axis]-self.origin[axis]
if abs(dist)>self.eps_collapse:
rel_shift[axis] = dist/self.spacing[axis]
return tuple(rel_shift)
def change_grid(self,origin,spacing,dim,padding=None,numpad=1):
assert all([origin[ii]>=self.origin[ii] for ii in range(0,3)]), "New origin is out of bounds."
endpoint = [origin[ii]+(dim[ii]-1)*spacing[ii] for ii in range(0,3)]
assert all([endpoint[ii]<=self.endpoint(ii) for ii in range(0,3)]), "New end point is out of bounds."
# Allocate (possibly padded array)
origin_pad,dim_pad,sl_out = padding(origin,spacing,dim,padding,numpad)
data = np.zeros(dim_pad,dtype=self.data.dtype)
# Trilinear interpolation
if np.allclose(spacing,self.spacing):
# spacing is the same: we can construct universal weights for the stencil
i0,j0,k0 = self.nearest_gridpoint(origin,axis=None,lower=True)
cx,cy,cz = [self.distance_to_nearest_gridpoint(origin[ii],axis=ii,lower=True)/self.spacing[ii]
for ii in range(3)]
c = self.weights_trilinear((cx,cy,cz))
for ii in range(0,2):
for jj in range(0,2):
for kk in range(0,2):
if c[ii,jj,kk]>self.eps_collapse:
data[sl_out] += c[ii,jj,kk]*self.data[
i0+ii:i0+ii+dim[0],
j0+jj:j0+jj+dim[1],
k0+kk:k0+kk+dim[2]]
else:
data_ref = data[sl_out]
for ii in range(0,dim[0]):
for jj in range(0,dim[1]):
for kk in range(0,dim[2]):
coord = (
origin[0]+ii*spacing[0],
origin[1]+jj*spacing[1],
origin[2]+kk*spacing[2])
data_ref[ii,jj,kk] = self.interpolate(coord)
return Field3d(data,origin_pad,spacing)
def interpolate(self,coord):
assert all([coord[ii]>=self.origin[ii] for ii in range(0,3)]), "'coord' is out of bounds."
assert all([coord[ii]<=self.endpoint(ii) for ii in range(0,3)]), "'coord' is out of bounds."
i0,j0,k0 = self.nearest_gridpoint(coord,axis=None,lower=True)
cx,cy,cz = [self.distance_to_nearest_gridpoint(coord[ii],axis=ii,lower=True)/self.spacing[ii]
for ii in range(3)]
c = self.weights_trilinear((cx,cy,cz))
val = 0.0
for ii in range(0,2):
for jj in range(0,2):
for kk in range(0,2):
if c[ii,jj,kk]>self.eps_collapse:
val += c[ii,jj,kk]*self.data[i0+ii,j0+jj,k0+kk]
return val
@staticmethod
def padding(origin,spacing,dim,padding,numpad):
if isinstance(numpad,int):
numpad = np.fill(3,numpad,dtype=int)
else:
numpad = np.array(numpad,dtype=int)
assert len(numpad)==3, "'numpad' must be either an integer or tuple/list of length 3."
origin_pad = np.array(origin)
dim_pad = np.array(dim)
sl_out = [slice(None),slice(None),slice(None)]
if padding is not None:
if padding=='before':
dim_pad += numpad
origin_pad -= numpad*spacing
for axis in range(3):
sl_out[axis] = slice(numpad[axis],None)
elif padding=='after':
dim_pad += numpad
for axis in range(3):
sl_out[axis] = slice(0,-numpad[axis])
elif padding=='both':
dim_pad += 2*numpad
origin_pad -= numpad*spacing
for axis in range(3):
sl_out[axis] = slice(numpad[axis],-numpad[axis])
else:
raise ValueError("'padding' must either be None or one of {'before','after','both'}.")
sl_out = tuple(sl_out)
origin_pad = tuple(origin_pad)
dim_pad = tuple(dim_pad)
return (origin_pad,dim_pad,sl_out)
def weights_trilinear(self,rel_dist):
assert len(rel_dist)==3, "len(rel_dist) must be 3."
cx,cy,cz = rel_dist
if cx<0.0 and cx>-self.eps_collapse: cx=0.0
if cy<0.0 and cy>-self.eps_collapse: cy=0.0
if cz<0.0 and cz>-self.eps_collapse: cz=0.0
if cx>1.0 and cx<1.0+self.eps_collapse: cx=1.0
if cy>1.0 and cy<1.0+self.eps_collapse: cy=1.0
if cz>1.0 and cz<1.0+self.eps_collapse: cz=1.0
assert cx>=0.0 and cy>=0.0 and cz>=0.0, "'rel_dist' must be >=0"
assert cx<=1.0 and cy<=1.0 and cz<=1.0, "'rel_dist' must be <=1"
c = np.zeros((2,2,2))
c[0,0,0] = 1.0-(cx+cy+cz)+(cx*cy+cx*cz+cy*cz)-(cx*cy*cz)
c[1,0,0] = cx-(cx*cy+cx*cz)+(cx*cy*cz)
c[0,1,0] = cy-(cx*cy+cy*cz)+(cx*cy*cz)
c[0,0,1] = cz-(cx*cz+cy*cz)+(cx*cy*cz)
c[1,1,0] = (cx*cy)-(cx*cy*cz)
c[1,0,1] = (cx*cz)-(cx*cy*cz)
c[0,1,1] = (cy*cz)-(cx*cy*cz)
c[1,1,1] = (cx*cy*cz)
return c
def set_writable(self,flag):
self.data.setflags(write=flag)
return
def to_vtk(self,deep=False):
import pyvista as pv
mesh = pv.UniformGrid()
mesh.dimensions = self.dim(axis=None)
mesh.origin = self.origin
mesh.spacing = self.spacing
# order needs to be F no matter how array is stored in memory
if deep:
mesh.point_arrays['data'] = self.data.flatten(order='F')
else:
if not self.data.flags['F_CONTIGUOUS']:
self.data = np.asfortranarray(self.data)
mesh.point_arrays['data'] = self.data.ravel(order='F')
return mesh
def vtk_contour(self,val,deep=False,method='contour'):
if not isinstance(val,(tuple,list)):
val = [val]
return self.to_vtk(deep=deep).contour(val,method=method)
def vtk_slice(self,normal,origin,deep=False):
assert (normal in ('x','y','z') or (isinstance(normal,(tuple,list))
and len(normal)==3)), "'normal' must be 'x','y','z' or tuple of length 3."
assert isinstance(origin,(tuple,list)) and len(origin)==3,\
"'origin' must be tuple of length 3."
return self.to_vtk(deep=deep).slice(normal=normal,origin=origin)
def gaussian_filter_umean_channel(array,spacing,sigma,truncate=4.0):
'''Applies a Gaussian filter to a numpy array of dimension (1,ny,1) which
contains the mean streamwise velocity of the channel (or possibly sth else).
Since yu[0] = c and yu[-1] = d, we can use scipy's mirror settings and don't
need ghost cells.'''
from scipy import ndimage
assert array.ndim==3, "Expected an array with three dimensions/axes."
assert array.shape[0]==1 and array.shape[1]>1 and array.shape[2]==1,\
"Expected an array with shape (1,ny,1)."
sigma_img = sigma/spacing
array = ndimage.gaussian_filter1d(array,sigma_img,axis=1,truncate=truncate,mode='mirror')
return array
class Features3d:
def __init__(self,input,threshold,origin,spacing,periodicity,connect_diagonals=True,invert=False,has_ghost=False):
assert len(origin)==3, "'origin' must be of length 3"
assert len(spacing)==3, "'spacing' must be of length 3"
assert len(periodicity)==3, "'periodicity' must be of length 3"
assert isinstance(input,np.ndarray), "'input' must be numpy.ndarray."
# Import libraries
import pyvista as pv
# Assign basic properties to class variables
self.origin = tuple(float(x) for x in origin)
self.spacing = tuple(float(x) for x in spacing)
self.periodicity = tuple(bool(x) for x in periodicity)
self._invert = invert
self._sldata = tuple(slice(0,-1) if x else None for x in periodicity)
# If regions are supposed to be inverted, i.e. the interior consists of values
# smaller than the threshold instead of larger, change the sign of the array.
sign_invert = -1 if invert else +1
self._threshold = threshold
# '_data' is the array which is to be triangulated. Here one trailing ghost cell is
# required to get closed surfaces. The data will always be copied since it probably
# needs to be copied for vtk anyway (needs FORTRAN contiguous array) and this way
# there will never be side effects on the input data.
if has_ghost:
self._data = np.asfortranarray(sign_invert*input)
else:
pw = tuple((0,1) if x else (0,0) for x in periodicity)
self._data = np.asfortranarray(np.pad(sign_invert*input,pw,mode='wrap'))
# 'binary' is a BinaryField which determines the connectivity of regions
# and provides morphological manipulations.
self.binary = BinaryFieldNd(self._data>=self._threshold,periodicity,
connect_diagonals=connect_diagonals,
deep=False,has_ghost=has_ghost)
# Compute features in 'binary' by labeling.
self.binary.label()
# Set arrays produced by triangulation to None
self._points = None
self._faces = None
@classmethod
def from_field(cls,fld,threshold,periodicity,invert=False,has_ghost=False):
return cls(fld.data,threshold,fld.origin,fld.spacing,periodicity,invert=invert,has_ghost=has_ghost)
@property
def threshold(self): return self._threshold
@property
def points(self): return self._points
@property
def faces(self): return self._faces
@property
def nfeatures(self): return self.binary.nlabels
def fill_holes(self):
self.binary.fill_holes()
li = ndimage.binary_erosion(self.binary._data)
self._data[li] = 2*self._threshold # arbitrary, only needs to be above threshold
if self._faces is not None:
self.triangulate(contour_method=self.__TRI_CONTMETH,
cellvol_normal_component=self.__TRI_NORMCOMP)
def reduce_noise(self,threshold=1e-5,is_relative=True):
'''Removes all objects with smaller (binary-based) volume than a threshold.'''
if is_relative:
threshold = threshold*self.binary.volume_domain()
vol = self.binary.volumes()
li = vol<threshold
mask = self.binary.discard_features(li,return_mask=True)
self._data[mask] = np.nan#self._threshold
if self._faces is not None:
self.triangulate(contour_method=self.__TRI_CONTMETH,
cellvol_normal_component=self.__TRI_NORMCOMP)
return
def triangulate(self,contour_method='flying_edges',cellvol_normal_component=2):
import pyvista as pv
from scipy import ndimage
from time import time
# Save arguments in case we need to recreate triangulation later on
self.__TRI_CONTMETH = contour_method
self.__TRI_NORMCOMP = cellvol_normal_component
# Wrap data with pyvista/VTK
datavtk = pv.UniformGrid()
datavtk.dimensions = self._data.shape
datavtk.origin = self.origin
datavtk.spacing = self.spacing
datavtk.point_arrays['data'] = self._data.ravel('F')
# Compute full contour: ensure we only have triangles to efficiently extract points
# later on.
t = time()
contour_ = datavtk.contour([self._threshold],method=contour_method,compute_scalars=False)
assert contour_.is_all_triangles(), "Contouring produced non-triangle cells."
print('CONTOUR:',time()-t)
# Interpolate labels from binary array: first the array needs to be
# dilated to ensure that we get proper values for the cell vertex interpolation.
t = time()
# labels_ = ndimage.grey_dilation(self.binary._labels,size=(3,3,3),mode='wrap')
labels_ = ndimage.maximum_filter(self.binary._labels,size=(3,3,3),mode='wrap')
print('DILATION:',time()-t)
# Labels are interpolated on points, and then the first point of each cell determines
# the value for this cell. This allows us to skip cell center computation and reduce
# the number of points which need to be interpolated. ndimage's 'map_coordinates' is
# the fastest interpolation routine I could find, but coordinates need to be provided
# as pixel values.
t = time()
pixel_coords = (contour_.points-self.origin)/self.spacing
point_val = ndimage.map_coordinates(labels_,pixel_coords.transpose(),order=0,mode='grid-wrap',prefilter=False)
cell_val = point_val[contour_.faces.reshape(contour_.n_faces,4)[:,1]]
print('INTERPOLATION:',time()-t)
# While we have the full contour in memory, compute the area and volume per cell. For
# the volume computation, an arbitrary component of the normal has to be chosen which
# defaults to the z-component and is set by 'cellvol_normal_component'.
t = time()
self._cell_areas = contour_.compute_cell_sizes(length=False,area=True,volume=False)["Area"]
self._cell_volumes = contour_.cell_normals[:,cellvol_normal_component]*\
contour_.cell_centers().points[:,cellvol_normal_component]*self._cell_areas
print('CELLPROPERTIES:',time()-t)
# Now the label is known per cell. We only need to find all cells with the same label
# and group them. Internally we will store the points in one array and the cells in
# nlabel tuples of ndarrays.
t = time()
offset = np.cumsum(np.bincount(cell_val))[1:-1]
ind = np.argsort(cell_val)
self._offset = offset
self._faces = contour_.faces.reshape(contour_.n_faces,4)[ind,:]
self._points = contour_.points
self._cell_areas = self._cell_areas[ind]
self._cell_volumes = self._cell_volumes[ind]
print('FINALIZING:',time()-t)
return
@property
def faces(self): return np.split(self._faces,self.offset)
@property
def points(self): return self._points
@property
def cell_areas(self): return np.split(self._cellarea,self.offset)
@property
def cell_volumes(self): return np.split(self._cellvol,self.offset)
def area(self,feature):
'''Returns the surface area of feature. If feature is None, total surface
area of all features is returned.'''
if label is None:
return np.sum(self._cell_areas)
else:
return np.sum(self.cell_areas[label-1])
def areas(self):
'''Returns a tuple with surface areas of all features.'''
return tuple(np.sum(x) for x in self.cell_areas)
def volume(self,feature,method='triangulation'):
'''Returns volume enclosed by feature. If feature isNone, total volume of
all features is returned.'''
if method=='triangulation':
if self._faces is None:
self.triangulate(contour_method=self.__TRI_CONTMETH,
cellvol_normal_component=self.__TRI_NORMCOMP)
if label is None:
return np.sum(self._cell_volumes)
else:
return np.sum(self.cell_volumes[feature-1])
elif method=='binary':
return self.binary.volume(feature)
else:
raise ValueError("Invalid method. Available methods: 'triangulation','binary'")
def volumes(self,method='triangulation'):
if method=='triangulation':
self.triangulate(contour_method=self.__TRI_CONTMETH,
cellvol_normal_component=self.__TRI_NORMCOMP)
return tuple(np.sum(x) for x in self.cell_volumes)
elif method=='binary':
return self.binary.volumes()
else:
raise ValueError("Invalid method. Available methods: 'triangulation','binary'")
def which_feature(self,coords,method='binary'):
coords = np.array(coords)
assert coords.ndim==2 and coords.shape[1]==3, "'coords' need to be provided as 3xN array."
if method=='binary':
idx = np.round()
# elif method=='triangulation':
return
def to_vtk(self,label,reduce_points=False):
if self._faces is None:
raise RuntimeError('Features have not been triangulated yet. Call triangulate() method first.')
import pyvista as pv
idx = label-1
if reduce_points:
nfaces_ = self._faces[idx].shape[0]
ind,inv = np.unique(self._faces[idx][:,1:4],return_inverse=True)
faces_ = np.zeros((nfaces_,4),dtype=self._faces[idx].dtype)
faces_[:,0] = 3
faces_[:,1:4] = inv.reshape(nfaces_,3)
points_ = self._points[ind,:]
return pv.PolyData(points_,faces_)
else:
return pv.PolyData(self._points,self._faces[idx])
class BinaryFieldNd:
def __init__(self,input,periodicity,connect_diagonals=False,deep=False,has_ghost=False):
assert isinstance(input,np.ndarray) and input.dtype==bool,\
"'input' must be a numpy array of type bool."
assert all([isinstance(x,(bool,int)) for x in periodicity]),\
"'periodicity' requires bool values."
assert len(periodicity)==input.ndim,\
"Number of entries in 'periodicity' must match dimension of binary field."
from scipy import ndimage
if has_ghost and deep:
self._data = input.copy()
elif has_ghost:
self._data = input
else:
pw = tuple((0,1) if x else (0,0) for x in periodicity)
self._data = np.pad(input,pw,mode='wrap')
self._sldata = tuple(slice(0,-1) if x else None for x in periodicity)
self._dim = self._data.shape
self._ndim = self._data.ndim
self._labels = None
self.nlabels = None
self.wrap = tuple(self._ndim*[None])
self.periodicity = tuple(bool(x) for x in periodicity)
if connect_diagonals:
self.structure = ndimage.generate_binary_structure(self._ndim,self._ndim)
else:
self.structure = ndimage.generate_binary_structure(self._ndim,1)
@property
def data(self):
return self._data[self._sldata]
@property
def labels(self):
if self._labels is None:
return None
return self._labels[self._sldata]
def label(self):
'''Labels connected regions in binary fields.'''
from scipy import ndimage
if any(self.periodicity):
self._labels,self.nlabels,self.wrap = self._labels_periodic()
else:
self._labels,self.nlabels = ndimage.label(self._data,structure=self.structure)
def _labels_periodic(self,map_to_zero=False):
'''Label features in an array while taking into account periodic wrapping.
If map_to_zero=True, every feature which overlaps or is attached to the
periodic boundary will be removed.'''
from scipy import ndimage
# Compute labels on padded array
labels_,nlabels_ = ndimage.label(self._data,structure=self.structure)
# Get a mapping of labels which differ at periodic overlap
map_ = np.array(range(nlabels_+1),dtype=labels_.dtype)
wrap_ = self._ndim*[None]
for axis in range(self._ndim):
if not self.periodicity[axis]: continue
sl_lo = tuple(slice(0,1) if ii==axis else slice(None) for ii in range(self._ndim))
sl_hi = tuple(slice(-1,None) if ii==axis else slice(None) for ii in range(self._ndim))
sl_pre = tuple(slice(-2,-1) if ii==axis else slice(None) for ii in range(self._ndim))
lab_lo = labels_[sl_lo]
lab_hi = labels_[sl_hi]
lab_pre = np.unique(labels_[sl_pre]) # all labels in last (unwrapped) slice
# Initialize array to keep track of wrapping
wrap_[axis] = np.zeros(nlabels_+1,dtype=bool)
# Determine new label and map
lab_new = np.minimum(lab_lo,lab_hi)
for lab_ in [lab_lo,lab_hi]:
li = (lab_!=lab_new) #if not map_to_zero else (lab_!=0)
lab_li = lab_[li]
lab_new_li = lab_new[li]
for idx_ in np.unique(lab_li,return_index=True)[1]:
source_ = lab_li[idx_] # the label to be changed
target_ = lab_new_li[idx_] # the label which will be newly assigned
if map_to_zero and source_ in lab_pre:
map_[source_] = 0
map_[target_] = 0
else:
while target_ != map_[target_]: # map it recursively
target_ = map_[target_]
map_[source_] = target_
if source_ in lab_pre: # check if source is not a ghost
wrap_[axis][target_] = True
# Remove gaps from target mapping
idx_,map_ = np.unique(map_,return_index=True,return_inverse=True)[1:3]
# Relabel and remove padding
labels_ = map_[labels_]
nlabels_ = np.max(map_)
assert nlabels_==len(idx_)-1, "DEBUG assertion"
self.wrap = tuple(None if x is None else x[idx_] for x in self.wrap)
# for axis in range(self._ndim):
# if wrap_[axis] is not None:
# wrap_[axis] = wrap_[axis][idx_]
return labels_,nlabels_,tuple(wrap_)
def fill_holes(self):
'''Fill the holes in binary objects while taking into account periodicity.
In the non-periodic sense, a hole is a region of zeros which does not connect
to a boundary. In the periodic sense, a hole is a region of zeros which is not
connected to itself accross the periodic boundaries.'''
from scipy import ndimage
# Reimplementation of "binary_fill_holes" from ndimage
mask = np.logical_not(self._data) # only modify locations which are "False" at the moment
tmp = np.zeros(mask.shape,bool) # create empty array to "grow from boundaries"
ndimage.binary_dilation(tmp,structure=None,iterations=-1,
mask=mask,output=self._data,border_value=1,
origin=0) # everything connected to the boundary is now True in self._data
# Remove holes which overlap the boundaries
if any(self.periodicity):
self._data = self._labels_periodic(map_to_zero=True)[0]>0
# Invert to get the final result
np.logical_not(self._data,self._data)
# If labels have been computed already, recompute them to stay consistent
if self._labels is not None:
self.label()
def probe(self,idx,probe_label=False):
'''Returns whether or not a point at idx is True or False.'''
if probe_label:
return self._labels[tuple(idx)]
else:
return self._data[tuple(idx)]
def volume(self,label):
'''Returns the sum of True values.'''
if label is None:
return np.sum(self.data)
else:
if self._labels is None: self.label()
return np.sum(self.labels==label)
def volumes(self):
'''Returns volume of all features, i.e. connected regions which have been
labeled using the label() method including the volume of the background region.
The array is sorted by labels, i.e. vol[0] is the volume of the background
region, vol[1] the volume of label 1, etc. If 'label' is an integer value,
only the volume of the corresponding region is returned.
Note: it is more efficient to retrieve all volumes at once than querying
single labels.'''
if self._labels is None: self.label()
return np.bincount(self.labels.ravel())
def volume_domain(self):
'''Returns volume of entire domain. Should be equal to sum(volume_feature()).'''
dim = tuple(self._dim[axis]-1 if self.periodicity[axis] else self._dim[axis] for axis in range(self._ndim))
return np.prod(dim)
def feature_labels_by_volume(self,descending=True,return_volumes=False):
'''Returns labels of connected regions sorted by volume.'''
vol = self.volumes()[1:]
labels = np.argsort(vol)+1
if descending:
labels = labels[::-1]
vol = vol[::-1]
if return_volumes:
return labels,vol
else:
return labels
def discard_features(self,selection,return_mask=False):
'''Removes features from data. Optionally returns a boolean array 'mask'
which marks position of features which have been removed.'''
if self._labels is None:
self.label()
selection = self._select_features(selection)
# Map tagged regions to zero in order to discard them
map_ = np.array(range(self.nlabels+1),dtype=self._labels.dtype)
map_[selection] = 0
# Remove gaps from target mapping
idx_,map_ = np.unique(map_,return_index=True,return_inverse=True)[1:3]
# Discard regions
self._labels = map_[self._labels]
self.nlabels = np.max(map_)
print(self.nlabels)
self.wrap = tuple(None if x is None else x[idx_] for x in self.wrap)
# for axis in range(self._ndim):
# if self.wrap[axis] is not None:
# self.wrap[axis] = self.wrap[axis][idx_]
if return_mask:
mask = np.logical_and(self._labels==0,self._data)
self._data = self._labels>0
if return_mask: return mask
def _select_features(self,selection):
dtype = self._labels.dtype
if selection is None:
return np.array(range(1,self.nlabels+1))
elif np.issubdtype(type(selection),np.integer):
return np.array(selection,dtype=dtype,ndmin=1)
elif isinstance(selection,(list,tuple,np.ndarray)):
selection = np.array(selection)
if selection.dtype==np.dtype('bool'):
assert selection.ndim==1 and selection.shape[0]==self.nlabels+1,\
"Boolean indexing must provide count+1 values."
else:
selection = selection.astype(dtype)
assert np.max(selection)<=self.nlabels and np.min(selection)>=0,\
"Entry in selection is out-of-bounds."
return selection
else:
raise ValueError('Invalid input. Accepting int,list,tuple,ndarray.')
class ChunkIterator:
'''Iterates through all chunks. 'snapshot' must be an instance
of a class which returns a Field3d from the method call
snapshot.field_chunk(rank,key,keep_ghost=keep_ghost).
One example implementation is UCFSnapshot from suspendtools.ucf.'''
def __init__(self,snapshot,key,keep_ghost=True):
self.snapshot = snapshot
self.key = key
self.keep_ghost = keep_ghost
self.iter_rank = 0
def __iter__(self):
self.iter_rank = 0
return self
def __next__(self):
if self.iter_rank<self.snapshot.nproc():
field = self.snapshot.field_chunk(
self.iter_rank,self.key,keep_ghost=self.keep_ghost)
self.iter_rank += 1
return field
else:
raise StopIteration