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authorDavid Cournapeau <cournape@gmail.com>2009-09-16 07:13:23 +0000
committerDavid Cournapeau <cournape@gmail.com>2009-09-16 07:13:23 +0000
commitf72c2dfd7d188f1ee9d795ba66c001aa7263c319 (patch)
treeacb0dac165305a66ed77e682ebedfb6ac6cb0c6a /numpy/lib
parenta0a2b2bba65baaa1ab88fef3995911c14adaf2d4 (diff)
downloadnumpy-f72c2dfd7d188f1ee9d795ba66c001aa7263c319.tar.gz
Move linspace and logspace into core.
Diffstat (limited to 'numpy/lib')
-rw-r--r--numpy/lib/function_base.py158
-rw-r--r--numpy/lib/tests/test_function_base.py36
-rw-r--r--numpy/lib/tests/test_index_tricks.py5
3 files changed, 7 insertions, 192 deletions
diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
index 663c3d2ef..2459ffc23 100644
--- a/numpy/lib/function_base.py
+++ b/numpy/lib/function_base.py
@@ -1,6 +1,5 @@
__docformat__ = "restructuredtext en"
-__all__ = ['logspace', 'linspace',
- 'select', 'piecewise', 'trim_zeros',
+__all__ = ['select', 'piecewise', 'trim_zeros',
'copy', 'iterable',
'diff', 'gradient', 'angle', 'unwrap', 'sort_complex', 'disp',
'extract', 'place', 'nansum', 'nanmax', 'nanargmax',
@@ -15,6 +14,7 @@ import warnings
import types
import numpy.core.numeric as _nx
+from numpy.core import linspace
from numpy.core.numeric import ones, zeros, arange, concatenate, array, \
asarray, asanyarray, empty, empty_like, ndarray, around
from numpy.core.numeric import ScalarType, dot, where, newaxis, intp, \
@@ -33,160 +33,6 @@ import numpy as np
#end Fernando's utilities
-def linspace(start, stop, num=50, endpoint=True, retstep=False):
- """
- Return evenly spaced numbers over a specified interval.
-
- Returns `num` evenly spaced samples, calculated over the
- interval [`start`, `stop` ].
-
- The endpoint of the interval can optionally be excluded.
-
- Parameters
- ----------
- start : scalar
- The starting value of the sequence.
- stop : scalar
- The end value of the sequence, unless `endpoint` is set to False.
- In that case, the sequence consists of all but the last of ``num + 1``
- evenly spaced samples, so that `stop` is excluded. Note that the step
- size changes when `endpoint` is False.
- num : int, optional
- Number of samples to generate. Default is 50.
- endpoint : bool, optional
- If True, `stop` is the last sample. Otherwise, it is not included.
- Default is True.
- retstep : bool, optional
- If True, return (`samples`, `step`), where `step` is the spacing
- between samples.
-
- Returns
- -------
- samples : ndarray
- There are `num` equally spaced samples in the closed interval
- ``[start, stop]`` or the half-open interval ``[start, stop)``
- (depending on whether `endpoint` is True or False).
- step : float (only if `retstep` is True)
- Size of spacing between samples.
-
-
- See Also
- --------
- arange : Similiar to `linspace`, but uses a step size (instead of the
- number of samples).
- logspace : Samples uniformly distributed in log space.
-
- Examples
- --------
- >>> np.linspace(2.0, 3.0, num=5)
- array([ 2. , 2.25, 2.5 , 2.75, 3. ])
- >>> np.linspace(2.0, 3.0, num=5, endpoint=False)
- array([ 2. , 2.2, 2.4, 2.6, 2.8])
- >>> np.linspace(2.0, 3.0, num=5, retstep=True)
- (array([ 2. , 2.25, 2.5 , 2.75, 3. ]), 0.25)
-
- Graphical illustration:
-
- >>> import matplotlib.pyplot as plt
- >>> N = 8
- >>> y = np.zeros(N)
- >>> x1 = np.linspace(0, 10, N, endpoint=True)
- >>> x2 = np.linspace(0, 10, N, endpoint=False)
- >>> plt.plot(x1, y, 'o')
- >>> plt.plot(x2, y + 0.5, 'o')
- >>> plt.ylim([-0.5, 1])
- >>> plt.show()
-
- """
- num = int(num)
- if num <= 0:
- return array([], float)
- if endpoint:
- if num == 1:
- return array([float(start)])
- step = (stop-start)/float((num-1))
- y = _nx.arange(0, num) * step + start
- y[-1] = stop
- else:
- step = (stop-start)/float(num)
- y = _nx.arange(0, num) * step + start
- if retstep:
- return y, step
- else:
- return y
-
-def logspace(start,stop,num=50,endpoint=True,base=10.0):
- """
- Return numbers spaced evenly on a log scale.
-
- In linear space, the sequence starts at ``base ** start``
- (`base` to the power of `start`) and ends with ``base ** stop``
- (see `endpoint` below).
-
- Parameters
- ----------
- start : float
- ``base ** start`` is the starting value of the sequence.
- stop : float
- ``base ** stop`` is the final value of the sequence, unless `endpoint`
- is False. In that case, ``num + 1`` values are spaced over the
- interval in log-space, of which all but the last (a sequence of
- length ``num``) are returned.
- num : integer, optional
- Number of samples to generate. Default is 50.
- endpoint : boolean, optional
- If true, `stop` is the last sample. Otherwise, it is not included.
- Default is True.
- base : float, optional
- The base of the log space. The step size between the elements in
- ``ln(samples) / ln(base)`` (or ``log_base(samples)``) is uniform.
- Default is 10.0.
-
- Returns
- -------
- samples : ndarray
- `num` samples, equally spaced on a log scale.
-
- See Also
- --------
- arange : Similiar to linspace, with the step size specified instead of the
- number of samples. Note that, when used with a float endpoint, the
- endpoint may or may not be included.
- linspace : Similar to logspace, but with the samples uniformly distributed
- in linear space, instead of log space.
-
- Notes
- -----
- Logspace is equivalent to the code
-
- >>> y = linspace(start, stop, num=num, endpoint=endpoint)
- >>> power(base, y)
-
- Examples
- --------
- >>> np.logspace(2.0, 3.0, num=4)
- array([ 100. , 215.443469 , 464.15888336, 1000. ])
- >>> np.logspace(2.0, 3.0, num=4, endpoint=False)
- array([ 100. , 177.827941 , 316.22776602, 562.34132519])
- >>> np.logspace(2.0, 3.0, num=4, base=2.0)
- array([ 4. , 5.0396842 , 6.34960421, 8. ])
-
- Graphical illustration:
-
- >>> import matplotlib.pyplot as plt
- >>> N = 10
- >>> x1 = np.logspace(0.1, 1, N, endpoint=True)
- >>> x2 = np.logspace(0.1, 1, N, endpoint=False)
- >>> y = np.zeros(N)
- >>> plt.plot(x1, y, 'o')
- >>> plt.plot(x2, y + 0.5, 'o')
- >>> plt.ylim([-0.5, 1])
- >>> plt.show()
-
- """
- y = linspace(start,stop,num=num,endpoint=endpoint)
- return _nx.power(base,y)
-
def iterable(y):
try: iter(y)
except: return 0
diff --git a/numpy/lib/tests/test_function_base.py b/numpy/lib/tests/test_function_base.py
index cfb316074..8595c6b5c 100644
--- a/numpy/lib/tests/test_function_base.py
+++ b/numpy/lib/tests/test_function_base.py
@@ -134,42 +134,6 @@ class TestSelect(TestCase):
assert_equal(len(choices),3)
assert_equal(len(conditions),3)
-class TestLogspace(TestCase):
- def test_basic(self):
- y = logspace(0,6)
- assert(len(y)==50)
- y = logspace(0,6,num=100)
- assert(y[-1] == 10**6)
- y = logspace(0,6,endpoint=0)
- assert(y[-1] < 10**6)
- y = logspace(0,6,num=7)
- assert_array_equal(y,[1,10,100,1e3,1e4,1e5,1e6])
-
-class TestLinspace(TestCase):
- def test_basic(self):
- y = linspace(0,10)
- assert(len(y)==50)
- y = linspace(2,10,num=100)
- assert(y[-1] == 10)
- y = linspace(2,10,endpoint=0)
- assert(y[-1] < 10)
- y,st = linspace(2,10,retstep=1)
- assert_almost_equal(st,8/49.0)
- assert_array_almost_equal(y,mgrid[2:10:50j],13)
-
- def test_corner(self):
- y = list(linspace(0,1,1))
- assert y == [0.0], y
- y = list(linspace(0,1,2.5))
- assert y == [0.0, 1.0]
-
- def test_type(self):
- t1 = linspace(0,1,0).dtype
- t2 = linspace(0,1,1).dtype
- t3 = linspace(0,1,2).dtype
- assert_equal(t1, t2)
- assert_equal(t2, t3)
-
class TestInsert(TestCase):
def test_basic(self):
a = [1,2,3]
diff --git a/numpy/lib/tests/test_index_tricks.py b/numpy/lib/tests/test_index_tricks.py
index d7e61799a..3307cef3e 100644
--- a/numpy/lib/tests/test_index_tricks.py
+++ b/numpy/lib/tests/test_index_tricks.py
@@ -24,6 +24,11 @@ class TestGrid(TestCase):
assert_almost_equal(b[-1],b[0]+19*0.1,11)
assert_almost_equal(a[1]-a[0],2.0/9.0,11)
+ def test_linspace_equivalence(self):
+ y,st = np.linspace(2,10,retstep=1)
+ assert_almost_equal(st,8/49.0)
+ assert_array_almost_equal(y,mgrid[2:10:50j],13)
+
def test_nd(self):
c = mgrid[-1:1:10j,-2:2:10j]
d = mgrid[-1:1:0.1,-2:2:0.2]