suspendtools/field.py

587 lines
27 KiB
Python

import numpy
class Field3d:
def __init__(self,data,origin,spacing):
assert len(origin)==3, "'origin' must be of length 3"
assert len(spacing)==3, "'spacing' must be of length 3"
self.data = numpy.array(data)
self.origin = tuple([float(x) for x in origin])
self.spacing = tuple([float(x) for x in spacing])
self.eps_collapse = 1e-12
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 __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
# 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 allocate(cls,dim,origin,spacing,fill=None,dtype=numpy.float64,pseudo=False):
'''Allocates an empty field, or a field filled with 'fill'.'''
assert isinstance(dim,(tuple,list,numpy.ndarray)) and len(dim)==3,\
"'dim' must be a tuple/list of length 3."
assert isinstance(origin,(tuple,list,numpy.ndarray)) and len(origin)==3,\
"'origin' must be a tuple/list of length 3."
assert isinstance(spacing,(tuple,list,numpy.ndarray)) and len(spacing)==3,\
"'spacing' must be a tuple/list of length 3."
if pseudo:
data = numpy.empty((0,0,0))
r = cls(data,origin,spacing)
r._dim = dim
return r
else:
if fill is None:
data = numpy.empty(dim,dtype=dtype)
else:
data = numpy.full(dim,fill,dtype=dtype)
return cls(data,origin,spacing)
def copy(self):
return Field3d(self.data.copy(),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."
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)):
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."
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].copy()
return Field3d(data,origin,spacing)
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 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 numpy.floor((coord+self.eps_collapse-self.origin[axis])/self.spacing[axis]).astype('int')
else:
return numpy.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 = numpy.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,numpy.array([-1.,1.])/self.spacing[axis],axis=axis,
mode='constant',cval=numpy.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,numpy.array([1.,-2.,1.])/self.spacing[0]**2,axis=0,mode='constant',cval=numpy.nan,origin=0)
data += ndimage.correlate1d(self.data,numpy.array([1.,-2.,1.])/self.spacing[1]**2,axis=1,mode='constant',cval=numpy.nan,origin=0)
data += ndimage.correlate1d(self.data,numpy.array([1.,-2.,1.])/self.spacing[2]**2,axis=2,mode='constant',cval=numpy.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,numpy.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 = numpy.sum(~numpy.isnan(self.data),axis=axes,keepdims=True)
func_sum = numpy.nansum
else:
func_sum = numpy.sum
if ufunc is None:
out = func_sum(self.data,axis=axes,keepdims=True)
else:
assert isinstance(ufunc,numpy.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,numpy.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=numpy.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,numpy.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):
# raise NotImplementedError("Routine has not been verified yet.")
# #TBD: verify this routine
# assert isinstance(rel_shift,(tuple,list,numpy.ndarray)) and len(rel_shift)==3,\
# "'shift' must be tuple/list with length 3."
# assert all([rel_shift[ii]>-1.0 and rel_shift[ii]<1.0 for ii in range(3)]),\
# "'shift' must be in (-1.0,1.0)."
# #data = numpy.full(self.dim,numpy.nan)
# data = self.data.copy()
# origin = list(self.origin)
# for axis in range(3):
# if abs(rel_shift[axis])<self.eps_collapse:
# continue
# origin[axis] += rel_shift[axis]*self.spacing[axis]
# sl_hi = 3*[slice(None)]
# sl_lo = 3*[slice(None)]
# sl_out = 3*[slice(None)]
# sl_clr = 3*[slice(None)]
# sl_hi[axis] = slice(1,None)
# sl_lo[axis] = slice(0,-1)
# if rel_shift[ii]<0.0:
# w = 1.0+rel_shift[axis]
# sl_out[axis] = slice(1,None)
# sl_clr[axis] = slice(0,1)
# else:
# w = rel_shift[axis]
# sl_out[axis] = slice(0,-1)
# sl_clr[axis] = slice(-1,None)
# sl_hi = tuple(sl_hi)
# sl_lo = tuple(sl_lo)
# sl_out = tuple(sl_out)
# sl_clr = tuple(sl_clr)
# data[sl_out] = (1.0-w)*data[sl_lo] + w*data[sl_hi]
# data[sl_clr] = numpy.nan
# return Field3d(data,origin,self.spacing)
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,numpy.ndarray)) and len(rel_shift)==3,\
"'shift' must be tuple/list with length 3."
assert all([rel_shift[ii]>=-1.0 and rel_shift[ii]<=1.0 for ii in range(3)]),\
"'shift' must be in (-1.0,1.0)."
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:
weights = (1.0-rel_shift[axis],rel_shift[axis])
data = ndimage.correlate1d(data,weights,axis=axis,mode='constant',cval=numpy.nan,origin=-1)
origin[axis] += rel_shift[axis]*self.spacing[axis]
if only_keep_interior:
sl[axis] = slice(0,-1)
else:
weights = (-rel_shift[axis],1.0+rel_shift[axis])
data = ndimage.correlate1d(data,weights,axis=axis,mode='constant',cval=numpy.nan,origin=0)
origin[axis] += rel_shift[axis]*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 = numpy.zeros(dim_pad,dtype=self.data.dtype)
# Trilinear interpolation
if numpy.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 = numpy.fill(3,numpad,dtype=int)
else:
numpad = numpy.array(numpad,dtype=int)
assert len(numpad)==3, "'numpad' must be either an integer or tuple/list of length 3."
origin_pad = numpy.array(origin)
dim_pad = numpy.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 = numpy.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:
mesh.point_arrays['data'] = self.data.ravel(order='F')
return mesh
def vtk_contour(self,val,deep=False):
if not isinstance(val,(tuple,list)):
val = [val]
return self.to_vtk(deep=deep).contour(val)
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 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