Source code for scitools.BoxGrid

#!/usr/bin/env python
"""
Class for uniform and non-uniform grid on an interval, rectangle, or box.
"""

from scitools.errorcheck import right_type, wrong_type
from scitools.numpyutils import ndgrid, ndarray, wrap2callable, array, \
     zeros, linspace

# constants for indexing the space directions:
X = X1 = 0
Y = X2 = 1
Z = X3 = 2


[docs]class UniformBoxGrid(object): """ Simple uniform grid on an interval, rectangle, box, or hypercube. ============= ==================================================== Attributes Description ============= ==================================================== nsd no of spatial dimensions in the grid min_coor array of minimum coordinates max_coor array of maximum coordinates division array of cell divisions in the delta array of grid spacings dirnames names of the space directions ('x', 'y', etc.) shape (nx+1, ny+1, ...); dimension of array over grid coor list of coordinates; self.coor[Y][j] is the the j-th coordinate in direction Y (=1) X, Y, Z are predefined constants 0, 1, 2 coorv expanded version of coor for vectorized expressions (in 2D, self.coorv[0] = self.coor[0][:,newaxis]) tolerance small geometric tolerance based on grid coordinates npoints total number of grid points ============= ==================================================== """
[docs] def __init__(self, min=(0,0), # minimum coordinates max=(1,1), # maximum coordinates division=(4,4), # cell divisions dirnames=('x', 'y', 'z')): # names of the directions """ Initialize a BoxGrid by giving domain range (minimum and maximum coordinates: min and max tuples/lists/arrays) and number of cells in each space direction (division tuple/list/array). The dirnames tuple/list holds the names of the coordinates in the various spatial directions. >>> g = UniformBoxGrid(min=0, max=1, division=10) >>> g = UniformBoxGrid(min=(0,-1), max=(1,1), division=(10,4)) >>> g = UniformBoxGrid(min=(0,0,-1), max=(2,1,1), division=(2,3,5)) """ # Allow int/float specifications in one-dimensional grids # (just turn to lists for later multi-dimensional processing) if isinstance(min, (int,float)): min = [min] if isinstance(max, (int,float)): max = [max] if isinstance(division, (int,float)): division = [division] if isinstance(dirnames, str): dirnames = [dirnames] self.nsd = len(min) # strip dirnames down to right space dim (in case the default # with three components were unchanged by the user): dirnames = dirnames[:self.nsd] # check consistent lengths: for a in max, division: if len(a) != self.nsd: raise ValueError( 'Incompatible lengths of arguments to constructor'\ ' (%d != %d)' % (len(a), self.nsd)) self.min_coor = array(min, float) self.max_coor = array(max, float) self.dirnames = dirnames self.division = division self.coor = [None]*self.nsd self.shape = [0]*self.nsd self.delta = zeros(self.nsd) for i in range(self.nsd): self.delta[i] = \ (self.max_coor[i] - self.min_coor[i])/float(self.division[i]) self.shape[i] = self.division[i] + 1 # no of grid points self.coor[i] = \ linspace(self.min_coor[i], self.max_coor[i], self.shape[i]) self._more_init()
def _more_init(self): self.shape = tuple(self.shape) self.coorv = ndgrid(*self.coor) if not isinstance(self.coorv, (list,tuple)): # 1D grid, wrap self.coorv as list: self.coorv = [self.coorv] self.npoints = 1 for i in range(len(self.shape)): self.npoints *= self.shape[i] self.tolerance = (max(self.max_coor) - min(self.min_coor))*1E-14 # nicknames: xcoor, ycoor, xcoorv, ycoorv, etc for i in range(self.nsd): self.__dict__[self.dirnames[i]+'coor'] = self.coor[i] self.__dict__[self.dirnames[i]+'coorv'] = self.coorv[i] if self.nsd == 3: # make boundary coordinates for vectorization: xdummy, \ self.ycoorv_xfixed_boundary, \ self.zcoorv_xfixed_boundary = ndgrid(0, self.ycoor, self.zcoor) self.xcoorv_yfixed_boundary, \ ydummy, \ self.zcoorv_yfixed_boundary = ndgrid(self.xcoor, 0, self.zcoor) self.xcoorv_yfixed_boundary, \ self.zcoorv_yfixed_boundary, \ zdummy = ndgrid(self.xcoor, self.ycoor, 0) # could have _ in all variable names and define read-only # access via properties
[docs] def string2griddata(s): """ Turn a text specification of a grid into a dictionary with the grid data. For example, >>> s = "domain=[0,10] indices=[0:11]" >>> data = BoxGrid.string2griddata(s) >>> data {'dirnames': ('x', 'y'), 'division': [10], 'max': [10], 'min': [0]} >>> s = "domain=[0.2,0.5]x[0,2E+00] indices=[0:20]x[0:100]" >>> data = BoxGrid.string2griddata(s) >>> data {'dirnames': ('x', 'y', 'z'), 'division': [19, 99], 'max': [0.5, 2], 'min': [0.2, 0]} >>> s = "[0,1]x[0,2]x[-1,1.5] [0:25]x[0:10]x[0:16]" >>> data = BoxGrid.string2griddata(s) >>> data {'dirnames': ('x', 'y', 'z'), 'division': [24, 9, 15], 'max': [1.0, 2.0, 1.5], 'min': [0.0, 0.0, -1.0]} The data dictionary can be used as keyword arguments to the class UniformBoxGrid constructor. """ domain = r'\[([^,]*),([^\]]*)\]' indices = r'\[([^:,]*):([^\]]*)\]' import re d = re.findall(domain, s) i = re.findall(indices, s) nsd = len(d) if nsd != len(i): raise ValueError('could not parse "%s"' % s) kwargs = {} dirnames = ('x', 'y', 'z') for dir in range(nsd): if not isinstance(d[dir], (list,tuple)) or len(d[dir]) != 2 or \ not isinstance(i[dir], (list,tuple)) or len(i[dir]) != 2: raise ValueError('syntax error in "%s"' % s) # old syntax (nx, xmin, xmax, ny, ymin, etc.): #kwargs[dirnames[dir]] = (float(d[dir][0]), float(d[dir][1])) #kwargs['n'+dirnames[dir]] = int(i[dir][1]) - int(i[dir][0]) # no of cells! kwargs['min'] = [float(d[dir][0]) for dir in range(nsd)] kwargs['max'] = [float(d[dir][1]) for dir in range(nsd)] kwargs['division'] = [int(i[dir][1]) - int(i[dir][0]) \ for dir in range(nsd)] kwargs['dirnames'] = dirnames[:nsd] return kwargs
string2griddata = staticmethod(string2griddata)
[docs] def __getitem__(self, i): """ Return access to coordinate array in direction no i, or direction name i, or return the coordinate of a point if i is an nsd-tuple. >>> g = UniformBoxGrid(x=(0,1), y=(-1,1), nx=2, ny=4) # xy grid >>> g[0][0] == g.min[0] # min coor in direction 0 True >>> g['x'][0] == g.min[0] # min coor in direction 'x' True >>> g[0,4] (0.0, 1.0) >>> g = UniformBoxGrid(min=(0,-1), max=(1,1), division=(2,4), dirnames=('y', 'z')) >>> g[1][0] == g.min[1] True >>> g['z'][0] == g.min[1] # min coor in direction 'z' True """ if isinstance(i, str): return self.coor[self.name2dirindex(i)] elif isinstance(i, int): if self.nsd > 1: return self.coor[i] # coordinate array else: return self.coor[0][i] # coordinate itself in 1D elif isinstance(i, (list,tuple)): return tuple([self.coor[k][i[k]] for k in range(len(i))]) else: wrong_type(i, 'i', 'Must be str, int, tuple')
[docs] def __setitem__(self, i, value): raise AttributeError('subscript assignment is not valid for '\ '%s instances' % self.__class__.__name__)
[docs] def ncells(self, i): """Return no of cells in direction i.""" # i has the meaning as in __getitem__. May be removed if not much used return len(self.coor[i])-1
[docs] def name2dirindex(self, name): """ Return direction index corresponding to direction name. In an xyz-grid, 'x' is 0, 'y' is 1, and 'z' is 2. In an yz-grid, 'x' is not defined, 'y' is 0, and 'z' is 1. """ try: return self.dirnames.index(name) except ValueError: print name, 'is not defined' return None
[docs] def dirindex2name(self, i): """Inverse of name2dirindex.""" try: return self.dirnames[i] except IndexError: print i, 'is not a valid index' return None
[docs] def ok(self): return True # constructor init only => always ok
[docs] def __len__(self): """Total number of grid points.""" n = 1 for dir in self.coor: n *= len(dir) return n
[docs] def __repr__(self): s = self.__class__.__name__ + \ '(min=%s, max=%s, division=%s, dirnames=%s)' % \ (self.min_coor.tolist(), self.max_coor.tolist(), self.division, self.dirnames) return s
[docs] def __str__(self): """Pretty print, using the syntax of init_fromstring.""" domain = 'x'.join(['[%g,%g]' % (min_, max_) \ for min_, max_ in zip(self.min_coor, self.max_coor)]) indices = 'x'.join(['[0:%d]' % div for div in self.division]) return 'domain=%s indices=%s' % (domain, indices)
[docs] def interpolator(self, point_values): """ Given a self.nsd dimension array point_values with values at each grid point, this method returns a function for interpolating the scalar field defined by point_values at an arbitrary point. 2D Example: given a filled array point_values[i,j], compute interpolator = grid.interpolator(point_values) v = interpolator(0.1243, 9.231) # interpolate point_values >>> g=UniformBoxGrid(x=(0,2), nx=2, y=(-1,1), ny=2) >>> g UniformBoxGrid(x=(0,2), nx=2, y=(-1,1), ny=2) >>> def f(x,y): return 2+2*x-y >>> f=g.vectorized_eval(f) >>> f array([[ 3., 2., 1.], [ 5., 4., 3.], [ 7., 6., 5.]]) >>> i=g.interpolator(f) >>> i(0.1,0.234) # interpolate (not a grid point) 1.9660000000000002 >>> f(0.1,0.234) # exact answer 1.9660000000000002 """ args = self.coor args.append(point_values) # make use of wrap2callable, which applies ScientificPython return wrap2callable(args)
[docs] def vectorized_eval(self, f): """ Evaluate a function f (of the space directions) over a grid. f is supposed to be vectorized. >>> g = BoxGrid(x=(0,1), y=(0,1), nx=3, ny=3) >>> # f(x,y) = sin(x)*exp(x-y): >>> a = g.vectorized_eval(lambda x,y: sin(x)*exp(y-x)) >>> print a [[ 0. 0. 0. 0. ] [ 0.23444524 0.3271947 0.45663698 0.63728825] [ 0.31748164 0.44308133 0.6183698 0.86300458] [ 0.30955988 0.43202561 0.60294031 0.84147098]] >>> # f(x,y) = 2: (requires special consideration) >>> a = g.vectorized_eval(lambda x,y: zeros(g.shape)+2) >>> print a [[ 2. 2. 2. 2.] [ 2. 2. 2. 2.] [ 2. 2. 2. 2.] [ 2. 2. 2. 2.]] """ a = f(*self.coorv) # check if f is really vectorized: try: msg = 'calling %s, which is supposed to be vectorized' % f.__name__ except AttributeError: # if __name__ is missing msg = 'calling a function, which is supposed to be vectorized' try: self.compatible(a) except (IndexError,TypeError), e: print 'e=',e, type(e), e.__class__.__name__ raise e.__class__('BoxGrid.vectorized_eval(f):\n%s, BUT:\n%s' % \ (msg, e)) return a
[docs] def init_fromstring(s): data = UniformBoxGrid.string2griddata(s) return UniformBoxGrid(**data)
init_fromstring = staticmethod(init_fromstring)
[docs] def compatible(self, data_array, name_of_data_array=''): """ Check that data_array is a NumPy array with dimensions compatible with the grid. """ if not isinstance(data_array, ndarray): raise TypeError('data %s is %s, not NumPy array' % \ (name_of_data_array, type(data_array))) else: if data_array.shape != self.shape: raise IndexError("data %s of shape %s is not "\ "compatible with the grid's shape %s" % \ (name_of_data_array, data_array.shape, self.shape)) return True # if we haven't raised any exceptions
[docs] def iter(self, domain_part='all', vectorized_version=True): """ Return iterator over grid points. domain_part = 'all': all grid points domain_part = 'interior': interior grid points domain_part = 'all_boundary': all boundary points domain_part = 'interior_boundary': interior boundary points domain_part = 'corners': all corner points domain_part = 'all_edges': all points along edges in 3D grids domain_part = 'interior_edges': interior points along edges vectorized_version is true if the iterator returns slice objects for the index slice in each direction. vectorized_version is false if the iterator visits each point at a time (scalar version). """ self.iterator_domain = domain_part self.vectorized_iter = vectorized_version return self
[docs] def __iter__(self): # Idea: set up slices for the various self.iterator_domain # values. In scalar mode, make a loop over the slices and # yield the scalar value. In vectorized mode, return the # appropriate slices. self._slices = [] # elements meant to be slice objects if self.iterator_domain == 'all': self._slices.append([]) for i in range(self.nsd): self._slices[-1].append((i, slice(0, len(self.coor[i]), 1))) elif self.iterator_domain == 'interior': self._slices.append([]) for i in range(self.nsd): self._slices[-1].append((i, slice(1, len(self.coor[i])-1, 1))) elif self.iterator_domain == 'all_boundary': for i in range(self.nsd): self._slices.append([]) # boundary i fixed at 0: for j in range(self.nsd): if j != i: self._slices[-1].\ append((j, slice(0, len(self.coor[j]), 1))) else: self._slices[-1].append((i, slice(0, 1, 1))) # boundary i fixed at its max value: for j in range(self.nsd): if j != i: self._slices[-1].\ append((j, slice(0, len(self.coor[j]), 1))) else: n = len(self.coor[i]) self._slices[-1].append((i, slice(n-1, n, 1))) elif self.iterator_domain == 'interior_boundary': for i in range(self.nsd): self._slices.append([]) # boundary i fixed at 0: for j in range(self.nsd): if j != i: self._slices[-1].\ append((j, slice(1, len(self.coor[j])-1, 1))) else: self._slices[-1].append((i, slice(0, 1, 1))) # boundary i fixed at its max value: for j in range(self.nsd): if j != i: self._slices[-1].\ append((j, slice(1, len(self.coor[j])-1, 1))) else: n = len(self.coor[i]) self._slices[-1].append((i, slice(n-1, n, 1))) elif self.iterator_domain == 'corners': if self.nsd == 1: for i0 in (0, len(self.coor[0])-1): self._slices.append([]) self._slices[-1].append((0, slice(i0, i0+1, 1))) elif self.nsd == 2: for i0 in (0, len(self.coor[0])-1): for i1 in (0, len(self.coor[1])-1): self._slices.append([]) self._slices[-1].append((0, slice(i0, i0+1, 1))) self._slices[-1].append((0, slice(i1, i1+1, 1))) elif self.nsd == 3: for i0 in (0, len(self.coor[0])-1): for i1 in (0, len(self.coor[1])-1): for i2 in (0, len(self.coor[2])-1): self._slices.append([]) self._slices[-1].append((0, slice(i0, i0+1, 1))) self._slices[-1].append((0, slice(i1, i1+1, 1))) self._slices[-1].append((0, slice(i2, i2+1, 1))) elif self.iterator_domain == 'all_edges': print 'iterator over "all_edges" is not implemented' elif self.iterator_domain == 'interior_edges': print 'iterator over "interior_edges" is not implemented' else: raise ValueError('iterator over "%s" is not impl.' % \ self.iterator_domain) # "def __next__(self):" """ If vectorized mode: Return list of slice instances, where the i-th element in the list represents the slice for the index in the i-th space direction (0,...,nsd-1). If scalar mode: Return list of indices (in multi-D) or the index (in 1D). """ if self.vectorized_iter: for s in self._slices: yield [slice_in_dir for dir, slice_in_dir in s] else: # scalar version for s in self._slices: slices = [slice_in_dir for dir, slice_in_dir in s] if len(slices) == 1: for i in xrange(slices[0].start, slices[0].stop): yield i elif len(slices) == 2: for i in xrange(slices[0].start, slices[0].stop): for j in xrange(slices[1].start, slices[1].stop): yield [i, j] elif len(slices) == 3: for i in xrange(slices[0].start, slices[0].stop): for j in xrange(slices[1].start, slices[1].stop): for k in xrange(slices[2].start, slices[2].stop): yield [i, j, k]
[docs] def locate_cell(self, point): """ Given a point (x, (x,y), (x,y,z)), locate the cell in which the point is located, and return 1) the (i,j,k) vertex index of the "lower-left" grid point in this cell, 2) the distances (dx, (dx,dy), or (dx,dy,dz)) from this point to the given point, 3) a boolean list if point matches the coordinates of any grid lines. If a point matches the last grid point in a direction, the cell index is set to the max index such that the (i,j,k) index can be used directly for look up in an array of values. The corresponding element in the distance array is then set 0. 4) the indices of the nearest grid point. The method only works for uniform grid spacing. Used for interpolation. >>> g1 = UniformBoxGrid(min=0, max=1, division=4) >>> cell_index, distance, match, nearest = g1.locate_cell(0.7) >>> print cell_index [2] >>> print distance [ 0.2] >>> print match [False] >>> print nearest [3] >>> >>> g1.locate_cell(0.5) ([2], array([ 0.]), [True], [2]) >>> >>> g2 = UniformBoxGrid.init_fromstring('[-1,1]x[-1,2] [0:3]x[0:4]') >>> print g2.coor [array([-1. , -0.33333333, 0.33333333, 1. ]), array([-1. , -0.25, 0.5 , 1.25, 2. ])] >>> g2.locate_cell((0.2,0.2)) ([1, 1], array([ 0.53333333, 0.45 ]), [False, False], [2, 2]) >>> g2.locate_cell((1,2)) ([3, 4], array([ 0., 0.]), [True, True], [3, 4]) >>> >>> >>> """ if isinstance(point, (int,float)): point = [point] nsd = len(point) if nsd != self.nsd: raise ValueError('point=%s has wrong dimension (this is a %dD grid!)' % \ (point, self.nsd)) #index = zeros(nsd, int) index = [0]*nsd distance = zeros(nsd) grid_point = [False]*nsd nearest_point = [0]*nsd for i, coor in enumerate(point): # is point inside the domain? if coor < self.min_coor[i] or coor > self.max_coor[i]: raise ValueError( 'locate_cell: point=%s is outside the domain [%s,%s]' % \ point, self.min_coor[i], self.max_coor[i]) index[i] = int((coor - self.min_coor[i])//self.delta[i]) # (need integer division) distance[i] = coor - (self.min_coor[i] + index[i]*self.delta[i]) if distance[i] > self.delta[i]/2: nearest_point[i] = index[i] + 1 else: nearest_point[i] = index[i] if abs(distance[i]) < self.tolerance: grid_point[i] = True nearest_point[i] = index[i] if (abs(distance[i] - self.delta[i])) < self.tolerance: # last cell, update index such that it coincides with the point grid_point[i] = True index[i] += 1 nearest_point[i] = index[i] distance[i] = 0.0 return index, distance, grid_point, nearest_point
[docs] def interpolate(v0, v1, x0, x1, x): return v0 + (v1-v0)/float(x1-x0)*(x-x0)
[docs] def gridline_slice(self, start_coor, direction=0, end_coor=None): """ Compute start and end indices of a line through the grid, and return a tuple that can be used as slice for the grid points along the line. The line must be in x, y or z direction (direction=0,1 or 2). If end_coor=None, the line ends where the grid ends. start_coor holds the coordinates of the start of the line. If start_coor does not coincide with one of the grid points, the line is snapped onto the grid (i.e., the line coincides with a grid line). Return: tuple with indices and slice describing the grid point indices that make up the line, plus a boolean "snapped" which is True if the original line did not coincide with any grid line, meaning that the returned line was snapped onto to the grid. >>> g2 = UniformBoxGrid.init_fromstring('[-1,1]x[-1,2] [0:3]x[0:4]') >>> print g2.coor [array([-1. , -0.33333333, 0.33333333, 1. ]), array([-1. , -0.25, 0.5 , 1.25, 2. ])] >>> g2.gridline_slice((-1, 0.5), 0) ((slice(0, 4, 1), 2), False) >>> g2.gridline_slice((-0.9, 0.4), 0) ((slice(0, 4, 1), 2), True) >>> g2.gridline_slice((-0.2, -1), 1) ((1, slice(0, 5, 1)), True) """ start_cell, start_distance, start_match, start_nearest = \ self.locate_cell(start_coor) # If snapping the line onto to the grid is not desired, the # start_cell and start_match lists must be used for interpolation # (i.e., interpolation is needed in the directions i where # start_match[i] is False). start_snapped = start_nearest[:] if end_coor is None: end_snapped = start_snapped[:] end_snapped[direction] = self.division[direction] # highest legal index else: end_cell, end_distance, end_match, end_nearest = \ self.locate_cell(end_coor) end_snapped = end_nearest[:] # recall that upper index limit must be +1 in a slice: line_slice = start_snapped[:] line_slice[direction] = \ slice(start_snapped[direction], end_snapped[direction]+1, 1) # note that if all start_match are true, then the plane # was not snapped return tuple(line_slice), not array(start_match).all()
[docs] def gridplane_slice(self, value, constant_coor=0): """ Compute a slice for a plane through the grid, defined by coor[constant_coor]=value. Return a tuple that can be used as slice, plus a boolean parameter "snapped" reflecting if the plane was snapped onto a grid plane (i.e., value did not correspond to an existing grid plane). """ start_coor = self.min_coor.copy() start_coor[constant_coor] = value start_cell, start_distance, start_match, start_nearest = \ self.locate_cell(start_coor) start_snapped = [0]*self.nsd start_snapped[constant_coor] = start_nearest[constant_coor] # recall that upper index limit must be +1 in a slice: end_snapped = [self.division[i] for i in range(self.nsd)] end_snapped[constant_coor] = start_snapped[constant_coor] plane_slice = [slice(start_snapped[i], end_snapped[i]+1, 1) \ for i in range(self.nsd)] plane_slice[constant_coor] = start_nearest[constant_coor] return tuple(plane_slice), not start_match[constant_coor]
[docs]class BoxGrid(UniformBoxGrid): """ Extension of class UniformBoxGrid to non-uniform box grids. The coordinate vectors (in each space direction) can have arbitrarily spaced coordinate values. The coor argument must be a list of nsd (number of space dimension) components, each component contains the grid coordinates in that space direction (stored as an array). """
[docs] def __init__(self, coor, dirnames=('x', 'y', 'z')): UniformBoxGrid.__init__(self, min=[a[0] for a in coor], max=[a[-1] for a in coor], division=[len(a)-1 for a in coor], dirnames=dirnames) # override: self.coor = coor
[docs] def __repr__(self): s = self.__class__.__name__ + '(coor=%s)' % self.coor return s
[docs] def locate_cell(self, point): raise NotImplementedError('Cannot locate point in cells in non-uniform grids')
def _test(g, points=None): print 'g=%s' % str(g) # dump all the contents of a grid object: import scitools.misc; scitools.misc.dump(g, hide_nonpublic=False) from numpy import zeros def fv(*args): # vectorized evaluation function return zeros(g.shape)+2 def fs(*args): # scalar version return 2 fv_arr = g.vectorized_eval(fv) fs_arr = zeros(g.shape) coor = [0.0]*g.nsd itparts = ['all', 'interior', 'all_boundary', 'interior_boundary', 'corners'] if g.nsd == 3: itparts += ['all_edges', 'interior_edges'] for domain_part in itparts: print '\niterator over "%s"' % domain_part for i in g.iter(domain_part, vectorized_version=False): if isinstance(i, int): i = [i] # wrap index as list (if 1D) for k in range(g.nsd): coor[k] = g.coor[k][i[k]] print i, coor if domain_part == 'all': # fs_arr shape corresponds to all points fs_arr[i] = fs(*coor) print 'vectorized iterator over "%s":' % domain_part for slices in g.iter(domain_part, vectorized_version=True): if domain_part == 'all': fs_arr[slices] = fv(*g.coor) # else: more complicated print slices # boundary slices... if points is not None: print '\n\nInterpolation in', g, '\n', g.coor for p in points: index, distance = g.locate_cell(p) print 'point %s is in cell %s, distance=%s' % (p, index, distance) def _test2(): g1 = UniformBoxGrid(min=0, max=1, division=4) _test(g1, [0.7, 0.5]) spec = '[0,1]x[-1,2] with indices [0:3]x[0:2]' g2 = UniformBoxGrid.init_fromstring(spec) _test(g2, [(0.2,0.2), (1,2)]) g3 = UniformBoxGrid(min=(0,0,-1), max=(1,1,1), division=(4,1,2)) _test(g3) print 'g3=\n%s' % str(g3) print 'g3[Z]=', g3[Z] print 'g3[Z][1] =', g3[Z][1] print 'dx, dy, dz spacings:', g3.delta g4 = UniformBoxGrid(min=(0,-1), max=(1,1), division=(4,2), dirnames=('y','z')) _test(g4) print 'g4["y"][-1]:', g4["y"][-1] def _test4(): from numpy import sin, zeros, exp # check vectorization evaluation: g = UniformBoxGrid(min=(0,0), max=(1,1), division=(3,3)) try: g.vectorized_eval(lambda x,y: 2) except TypeError, msg: # fine, expect to arrive here print '*** Expected error in this test:', msg try: g.vectorized_eval(lambda x,y: zeros((2,2))+2) except IndexError, msg: # fine, expect to arrive here print '*** Expected error in this test:', msg a = g.vectorized_eval(lambda x,y: sin(x)*exp(y-x)) print a a = g.vectorized_eval(lambda x,y: zeros(g.shape)+2) print a if __name__ == '__main__': _test2() #_test4()