util¶
The util module provides a collection of general purpose methods.

nutils.util.
sum
()¶ reduce(function, sequence[, initial]) > value
Apply a function of two arguments cumulatively to the items of a sequence, from left to right, so as to reduce the sequence to a single value. For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates ((((1+2)+3)+4)+5). If initial is present, it is placed before the items of the sequence in the calculation, and serves as a default when the sequence is empty.

nutils.util.
product
()¶ reduce(function, sequence[, initial]) > value
Apply a function of two arguments cumulatively to the items of a sequence, from left to right, so as to reduce the sequence to a single value. For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates ((((1+2)+3)+4)+5). If initial is present, it is placed before the items of the sequence in the calculation, and serves as a default when the sequence is empty.

class
nutils.util.
NanVec
(length)¶ Bases:
numpy.ndarray
naninitialized vector

nutils.util.
tri_merge
(tri, x, mergetol=0)¶ Create connected triangulation by connecting (near) identical points.
Based on a set of coordinates
x
, create a modified copy oftri
with any occurrence ofj
replaced byi
ifx[i]
equalsx[j]
within specified tolerance. The result is a triangulation that remains valid for any associated data vector that follows the same equality relations.Example:
>>> x = [0,0], [1,0], [0,1], [1,0], [1,1] # note: x[1] == x[3]) >>> tri = [0,1,2], [2,3,4] >>> tri_merge(tri, x) array([[0, 1, 2], [2, 1, 4]])
Requires scipy.
 Parameters
x (
float
array) – Vertex coordinates.tri (
int
array) – Triangulation.mergetol (
float
(optional, default 0)) – Distance within which two points are considered equal. If mergetol == 0 then points are considered equal if and only if their coordinates are identical. If mergetol > 0 (required scipy) then points are considered equal if they are within euclidian distance < mergetol. If mergetol < 0 then tri is returned unchanged.
 Returns
merged_tri
 Return type
int
array

class
nutils.util.
tri_interpolator
(tri, x, mergetol=0)¶ Bases:
object
Interpolate function values defined in triangulation vertices.
Convenience object that implements 2D interpolation on top of matplotlib’s triangulation routines. Unlike matplotlib’s own
LinearTriInterpolator
, thetri_interpolator
allows for interpolation of multidimensional arrays, as well as repeated interpolations of different vertex values.The arguments are identical to
tri_merge()
.After instantiation of the interpolator object, interpolation coordinates are specified via the object’s getitem operator. The resulting callable performs the interpolation:
>>> trix = [0,0], [1,0], [0,1], [1,1] # vertex coordinates >>> triu = 0, 0, 10, 0 # vertex values >>> interpolate = tri_interpolator([[0,1,2],[1,3,2]], trix) >>> x = [.1,.1], [.1,.9], [.9,.9] # interpolation coordinates >>> u = interpolate[x](triu) # interpolated values
Requires matplotlib.

__weakref__
¶ list of weak references to the object (if defined)


nutils.util.
obj2str
(obj)¶ compact, lossy string representation of arbitrary object

nutils.util.
single_or_multiple
(f)¶ Method wrapper, converts first positional argument to tuple: tuples/lists are passed on as tuples, other objects are turned into tuple singleton. Return values should match the length of the argument list, and are unpacked if the original argument was not a tuple/list.
>>> class Test: ... @single_or_multiple ... def square(self, args): ... return [v**2 for v in args] ... >>> T = Test() >>> T.square(2) 4 >>> T.square([2,3]) (4, 9)
 Parameters
f (
callable
) – Method that expects a tuple as first positional argument, and that returns a list/tuple of the same length. Returns
Wrapped method.

nutils.util.
positional_only
(f)¶ Change all positionalorkeyword arguments to positionalonly.
Python has no explicit syntax for defining positionalonly parameters, but the effect can be achieved by using a wrapper with a varpositional argument. The
positional_only()
decorator uses this technique to treat all positionalorkeyword arguments as positionalonly. In order to avoid name clashes between the positionalonly arguments and variable keyword arguments, the wrapper additionally introduces the convention that the last argument receives the variable keyword argument dictionary in case is has a default value of … (ellipsis).Example:
>>> @positional_only ... def f(x, *, y): ... pass >>> inspect.signature(f) <Signature (x, /, *, y)>
>>> @positional_only ... def f(x, *args, y, kwargs=...): ... pass >>> inspect.signature(f) <Signature (x, /, *args, y, **kwargs)>
 Parameters
f (
callable
) – Function to be wrapped.

nutils.util.
loadlib
(**libname)¶ Find and load a dynamic library using
ctypes.CDLL
. For each (supported) platform the name of the library should be specified as a keyword argument, including the extension, where the keywords should match the possible values ofsys.platform
. In addition to the default directories, this function searchessite.PREFIXES
andsite.getuserbase()
.Example
To load the Intel MKL runtime library, write:
loadlib(linux='libmkl_rt.so', darwin='libmkl_rt.dylib', win32='mkl_rt.dll')

nutils.util.
readtext
(path)¶ Read file and return contents
 Parameters
path (
os.PathLike
,str
orio.TextIOBase
) – Pathlike or filelike object pointing to the data to be read. Returns
File data as
str
.