python类byte_bounds()的实例源码

pool.py 文件源码 项目:Parallel-SGD 作者: angadgill 项目源码 文件源码 阅读 43 收藏 0 点赞 0 评论 0
def _reduce_memmap_backed(a, m):
    """Pickling reduction for memmap backed arrays

    a is expected to be an instance of np.ndarray (or np.memmap)
    m is expected to be an instance of np.memmap on the top of the ``base``
    attribute ancestry of a. ``m.base`` should be the real python mmap object.
    """
    # offset that comes from the striding differences between a and m
    a_start, a_end = np.byte_bounds(a)
    m_start = np.byte_bounds(m)[0]
    offset = a_start - m_start

    # offset from the backing memmap
    offset += m.offset

    if m.flags['F_CONTIGUOUS']:
        order = 'F'
    else:
        # The backing memmap buffer is necessarily contiguous hence C if not
        # Fortran
        order = 'C'

    if a.flags['F_CONTIGUOUS'] or a.flags['C_CONTIGUOUS']:
        # If the array is a contiguous view, no need to pass the strides
        strides = None
        total_buffer_len = None
    else:
        # Compute the total number of items to map from which the strided
        # view will be extracted.
        strides = a.strides
        total_buffer_len = (a_end - a_start) // a.itemsize
    return (_strided_from_memmap,
            (m.filename, a.dtype, m.mode, offset, order, a.shape, strides,
             total_buffer_len))
utils.py 文件源码 项目:radar 作者: amoose136 项目源码 文件源码 阅读 28 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------
utils.py 文件源码 项目:krpcScripts 作者: jwvanderbeck 项目源码 文件源码 阅读 36 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------
utils.py 文件源码 项目:aws-lambda-numpy 作者: vitolimandibhrata 项目源码 文件源码 阅读 21 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------
utils.py 文件源码 项目:lambda-numba 作者: rlhotovy 项目源码 文件源码 阅读 50 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------
utils.py 文件源码 项目:deliver 作者: orchestor 项目源码 文件源码 阅读 27 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------
utils.py 文件源码 项目:Alfred 作者: jkachhadia 项目源码 文件源码 阅读 19 收藏 0 点赞 0 评论 0
def byte_bounds(a):
    """
    Returns pointers to the end-points of an array.

    Parameters
    ----------
    a : ndarray
        Input array. It must conform to the Python-side of the array
        interface.

    Returns
    -------
    (low, high) : tuple of 2 integers
        The first integer is the first byte of the array, the second
        integer is just past the last byte of the array.  If `a` is not
        contiguous it will not use every byte between the (`low`, `high`)
        values.

    Examples
    --------
    >>> I = np.eye(2, dtype='f'); I.dtype
    dtype('float32')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True
    >>> I = np.eye(2, dtype='G'); I.dtype
    dtype('complex192')
    >>> low, high = np.byte_bounds(I)
    >>> high - low == I.size*I.itemsize
    True

    """
    ai = a.__array_interface__
    a_data = ai['data'][0]
    astrides = ai['strides']
    ashape = ai['shape']
    bytes_a = asarray(a).dtype.itemsize

    a_low = a_high = a_data
    if astrides is None:
        # contiguous case
        a_high += a.size * bytes_a
    else:
        for shape, stride in zip(ashape, astrides):
            if stride < 0:
                a_low += (shape-1)*stride
            else:
                a_high += (shape-1)*stride
        a_high += bytes_a
    return a_low, a_high


#-----------------------------------------------------------------------------
# Function for output and information on the variables used.
#-----------------------------------------------------------------------------


问题


面经


文章

微信
公众号

扫码关注公众号