def __getitem__(self, key):
try:
size = []
typ = int
for k in range(len(key)):
step = key[k].step
start = key[k].start
if start is None:
start = 0
if step is None:
step = 1
if isinstance(step, complex):
size.append(int(abs(step)))
typ = float
else:
size.append(
int(math.ceil((key[k].stop - start)/(step*1.0))))
if (isinstance(step, float) or
isinstance(start, float) or
isinstance(key[k].stop, float)):
typ = float
if self.sparse:
nn = [_nx.arange(_x, dtype=_t)
for _x, _t in zip(size, (typ,)*len(size))]
else:
nn = _nx.indices(size, typ)
for k in range(len(size)):
step = key[k].step
start = key[k].start
if start is None:
start = 0
if step is None:
step = 1
if isinstance(step, complex):
step = int(abs(step))
if step != 1:
step = (key[k].stop - start)/float(step-1)
nn[k] = (nn[k]*step+start)
if self.sparse:
slobj = [_nx.newaxis]*len(size)
for k in range(len(size)):
slobj[k] = slice(None, None)
nn[k] = nn[k][slobj]
slobj[k] = _nx.newaxis
return nn
except (IndexError, TypeError):
step = key.step
stop = key.stop
start = key.start
if start is None:
start = 0
if isinstance(step, complex):
step = abs(step)
length = int(step)
if step != 1:
step = (key.stop-start)/float(step-1)
stop = key.stop + step
return _nx.arange(0, length, 1, float)*step + start
else:
return _nx.arange(start, stop, step)
def triu_indices(n, k=0, m=None):
"""
Return the indices for the upper-triangle of an (n, m) array.
Parameters
----------
n : int
The size of the arrays for which the returned indices will
be valid.
k : int, optional
Diagonal offset (see `triu` for details).
m : int, optional
.. versionadded:: 1.9.0
The column dimension of the arrays for which the returned
arrays will be valid.
By default `m` is taken equal to `n`.
Returns
-------
inds : tuple, shape(2) of ndarrays, shape(`n`)
The indices for the triangle. The returned tuple contains two arrays,
each with the indices along one dimension of the array. Can be used
to slice a ndarray of shape(`n`, `n`).
See also
--------
tril_indices : similar function, for lower-triangular.
mask_indices : generic function accepting an arbitrary mask function.
triu, tril
Notes
-----
.. versionadded:: 1.4.0
Examples
--------
Compute two different sets of indices to access 4x4 arrays, one for the
upper triangular part starting at the main diagonal, and one starting two
diagonals further right:
>>> iu1 = np.triu_indices(4)
>>> iu2 = np.triu_indices(4, 2)
Here is how they can be used with a sample array:
>>> a = np.arange(16).reshape(4, 4)
>>> a
array([[ 0, 1, 2, 3],
[ 4, 5, 6, 7],
[ 8, 9, 10, 11],
[12, 13, 14, 15]])
Both for indexing:
>>> a[iu1]
array([ 0, 1, 2, ..., 10, 11, 15])
And for assigning values:
>>> a[iu1] = -1
>>> a
array([[-1, -1, -1, -1],
[ 4, -1, -1, -1],
[ 8, 9, -1, -1],
[12, 13, 14, -1]])
These cover only a small part of the whole array (two diagonals right
of the main one):
>>> a[iu2] = -10
>>> a
array([[ -1, -1, -10, -10],
[ 4, -1, -1, -10],
[ 8, 9, -1, -1],
[ 12, 13, 14, -1]])
"""
tri_ = ~tri(n, m, k=k - 1, dtype=bool)
return tuple(
broadcast_to(inds, tri_.shape)[tri_]
for inds in indices(tri_.shape, sparse=True))
def __getitem__(self, key):
try:
size = []
typ = int
for k in range(len(key)):
step = key[k].step
start = key[k].start
if start is None:
start = 0
if step is None:
step = 1
if isinstance(step, complex):
size.append(int(abs(step)))
typ = float
else:
size.append(
int(math.ceil((key[k].stop - start) / (step * 1.0))))
if (isinstance(step, float) or isinstance(start, float)
or isinstance(key[k].stop, float)):
typ = float
if self.sparse:
nn = [
_nx.arange(_x, dtype=_t)
for _x, _t in zip(size, (typ, ) * len(size))
]
else:
nn = _nx.indices(size, typ)
for k in range(len(size)):
step = key[k].step
start = key[k].start
if start is None:
start = 0
if step is None:
step = 1
if isinstance(step, complex):
step = int(abs(step))
if step != 1:
step = (key[k].stop - start) / float(step - 1)
nn[k] = (nn[k] * step + start)
if self.sparse:
slobj = [_nx.newaxis] * len(size)
for k in range(len(size)):
slobj[k] = slice(None, None)
nn[k] = nn[k][slobj]
slobj[k] = _nx.newaxis
return nn
except (IndexError, TypeError):
step = key.step
stop = key.stop
start = key.start
if start is None:
start = 0
if isinstance(step, complex):
step = abs(step)
length = int(step)
if step != 1:
step = (key.stop - start) / float(step - 1)
stop = key.stop + step
return _nx.arange(0, length, 1, float) * step + start
else:
return _nx.arange(start, stop, step)