132 lines
4.6 KiB
ReStructuredText
132 lines
4.6 KiB
ReStructuredText
=========================
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NumPy 1.5.0 Release Notes
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=========================
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Highlights
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==========
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Python 3 compatibility
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----------------------
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This is the first NumPy release which is compatible with Python 3. Support for
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Python 3 and Python 2 is done from a single code base. Extensive notes on
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changes can be found at
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`<http://projects.scipy.org/numpy/browser/trunk/doc/Py3K.txt>`_.
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Note that the Numpy testing framework relies on nose, which does not have a
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Python 3 compatible release yet. A working Python 3 branch of nose can be found
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at `<http://bitbucket.org/jpellerin/nose3/>`_ however.
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Porting of SciPy to Python 3 is expected to be completed soon.
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:pep:`3118` compatibility
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-------------------------
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The new buffer protocol described by PEP 3118 is fully supported in this
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version of Numpy. On Python versions >= 2.6 Numpy arrays expose the buffer
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interface, and array(), asarray() and other functions accept new-style buffers
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as input.
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New features
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============
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Warning on casting complex to real
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----------------------------------
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Numpy now emits a `numpy.ComplexWarning` when a complex number is cast
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into a real number. For example:
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>>> x = np.array([1,2,3])
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>>> x[:2] = np.array([1+2j, 1-2j])
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ComplexWarning: Casting complex values to real discards the imaginary part
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The cast indeed discards the imaginary part, and this may not be the
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intended behavior in all cases, hence the warning. This warning can be
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turned off in the standard way:
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>>> import warnings
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>>> warnings.simplefilter("ignore", np.ComplexWarning)
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Dot method for ndarrays
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-----------------------
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Ndarrays now have the dot product also as a method, which allows writing
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chains of matrix products as
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>>> a.dot(b).dot(c)
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instead of the longer alternative
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>>> np.dot(a, np.dot(b, c))
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linalg.slogdet function
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-----------------------
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The slogdet function returns the sign and logarithm of the determinant
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of a matrix. Because the determinant may involve the product of many
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small/large values, the result is often more accurate than that obtained
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by simple multiplication.
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new header
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----------
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The new header file ndarraytypes.h contains the symbols from
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ndarrayobject.h that do not depend on the PY_ARRAY_UNIQUE_SYMBOL and
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NO_IMPORT/_ARRAY macros. Broadly, these symbols are types, typedefs,
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and enumerations; the array function calls are left in
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ndarrayobject.h. This allows users to include array-related types and
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enumerations without needing to concern themselves with the macro
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expansions and their side- effects.
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Changes
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=======
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polynomial.polynomial
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---------------------
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* The polyint and polyder functions now check that the specified number
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integrations or derivations is a non-negative integer. The number 0 is
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a valid value for both functions.
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* A degree method has been added to the Polynomial class.
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* A trimdeg method has been added to the Polynomial class. It operates like
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truncate except that the argument is the desired degree of the result,
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not the number of coefficients.
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* Polynomial.fit now uses None as the default domain for the fit. The default
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Polynomial domain can be specified by using [] as the domain value.
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* Weights can be used in both polyfit and Polynomial.fit
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* A linspace method has been added to the Polynomial class to ease plotting.
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* The polymulx function was added.
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polynomial.chebyshev
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--------------------
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* The chebint and chebder functions now check that the specified number
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integrations or derivations is a non-negative integer. The number 0 is
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a valid value for both functions.
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* A degree method has been added to the Chebyshev class.
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* A trimdeg method has been added to the Chebyshev class. It operates like
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truncate except that the argument is the desired degree of the result,
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not the number of coefficients.
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* Chebyshev.fit now uses None as the default domain for the fit. The default
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Chebyshev domain can be specified by using [] as the domain value.
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* Weights can be used in both chebfit and Chebyshev.fit
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* A linspace method has been added to the Chebyshev class to ease plotting.
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* The chebmulx function was added.
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* Added functions for the Chebyshev points of the first and second kind.
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histogram
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---------
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After a two years transition period, the old behavior of the histogram function
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has been phased out, and the "new" keyword has been removed.
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correlate
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---------
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The old behavior of correlate was deprecated in 1.4.0, the new behavior (the
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usual definition for cross-correlation) is now the default.
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