Beispiel #1
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 def test_nans_6(self):
     "afunc.nans_6"
     shape = 0
     dtype = str
     actual = nans(shape, dtype)    
     desired = np.zeros(shape, dtype=dtype)
     assert_equal(actual, desired) 
Beispiel #2
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 def test_nans_4(self):
     "afunc.nans_4"
     shape = (2,)
     dtype = object
     actual = nans(shape, dtype)
     desired = np.array([None, None])
     assert_equal(actual, desired)
Beispiel #3
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 def test_nans_2(self):
     "afunc.nans_2"
     shape = (2,)
     dtype = float
     actual = nans(shape, dtype)    
     desired = np.array([nan, nan]) 
     assert_almost_equal(actual, desired)       
Beispiel #4
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 def test_nans_3(self):
     "afunc.nans_3"
     shape = (2,)
     dtype = str
     actual = nans(shape, dtype)    
     desired = np.array(['', ''])
     assert_equal(actual, desired) 
Beispiel #5
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 def test_nans_5(self):
     "afunc.nans_5"
     shape = (2, 4, 3)
     dtype = object
     actual = nans(shape, dtype)    
     desired = np.zeros(shape, dtype=dtype)
     desired[:] = None
     assert_equal(actual, desired)
Beispiel #6
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Datei: move.py Projekt: fhal/la
def move_func_strides(func, arr, window, axis=-1, **kwargs):
    "Generic moving window function implemented with strides."
    if axis == None:
        raise ValueError, "An `axis` value of None is not supported."
    if window < 1:  
        raise ValueError, "`window` must be at least 1."
    if window > arr.shape[axis]:
        raise ValueError, "`window` is too long."
    ndim = arr.ndim
    as_strided = np.lib.stride_tricks.as_strided
    idx = range(ndim)
    axis = idx[axis]
    arrshape0 = tuple(arr.shape)
    if axis >= ndim:
        raise IndexError, "`axis` is out of range."
    if ndim == 1:
        strides = arr.strides
        shape = (arr.size - window + 1, window)
        strides = 2 * strides
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
    elif ndim == 2:
        if axis == 1:
            arr = arr.T
        strides = arr.strides
        shape = (arr.shape[0] - window + 1, window, arr.shape[1]) 
        strides = (strides[0],) + strides 
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
        if axis == 1:
            y = y.T    
    elif ndim == 3:
        if axis > 0:
            arr = arr.swapaxes(0, axis)
        strides = arr.strides
        shape = (arr.shape[0]-window+1, window, arr.shape[1], arr.shape[2])
        strides = (strides[0],) + strides
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
        if axis > 0:
            y = y.swapaxes(0, axis)
    else:
        raise ValueError, "Only 1d, 2d, and 3d input arrays are supported."
    ynan = nans(arrshape0)
    index = [slice(None)] * ndim 
    index[axis] = slice(window - 1, None)
    ynan[index] = y
    return ynan
Beispiel #7
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def move_func_strides(func, arr, window, axis=-1, **kwargs):
    "Generic moving window function implemented with strides."
    if axis is None:
        raise ValueError("An `axis` value of None is not supported.")
    if window < 1:
        raise ValueError("`window` must be at least 1.")
    if window > arr.shape[axis]:
        raise ValueError("`window` is too long.")
    ndim = arr.ndim
    as_strided = np.lib.stride_tricks.as_strided
    idx = range(ndim)
    axis = idx[axis]
    arrshape0 = tuple(arr.shape)
    if axis >= ndim:
        raise IndexError("`axis` is out of range.")
    if ndim == 1:
        strides = arr.strides
        shape = (arr.size - window + 1, window)
        strides = 2 * strides
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
    elif ndim == 2:
        if axis == 1:
            arr = arr.T
        strides = arr.strides
        shape = (arr.shape[0] - window + 1, window, arr.shape[1])
        strides = (strides[0], ) + strides
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
        if axis == 1:
            y = y.T
    elif ndim == 3:
        if axis > 0:
            arr = arr.swapaxes(0, axis)
        strides = arr.strides
        shape = (arr.shape[0] - window + 1, window, arr.shape[1], arr.shape[2])
        strides = (strides[0], ) + strides
        z = as_strided(arr, shape=shape, strides=strides)
        y = func(z, axis=1, **kwargs)
        if axis > 0:
            y = y.swapaxes(0, axis)
    else:
        raise ValueError("Only 1d, 2d, and 3d input arrays are supported.")
    ynan = nans(arrshape0)
    index = [slice(None)] * ndim
    index[axis] = slice(window - 1, None)
    ynan[index] = y
    return ynan
Beispiel #8
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Datei: move.py Projekt: fhal/la
def move_func_loop(func, arr, window, axis=-1, **kwargs):
    "Generic moving window function implemented with a python loop."
    if axis == None:
        raise ValueError, "An `axis` value of None is not supported."
    if window < 1:  
        raise ValueError, "`window` must be at least 1."
    if window > arr.shape[axis]:
        raise ValueError, "`window` is too long."
    y = nans(arr.shape)
    idx1 = [slice(None)] * arr.ndim
    idx2 = list(idx1)
    for i in range(window - 1, arr.shape[axis]):
        idx1[axis] = slice(i + 1 - window, i + 1)
        idx2[axis] = i
        y[idx2] = func(arr[idx1], axis=axis, **kwargs)
    return y    
Beispiel #9
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def move_func_loop(func, arr, window, axis=-1, **kwargs):
    "Generic moving window function implemented with a python loop."
    if axis is None:
        raise ValueError("An `axis` value of None is not supported.")
    if window < 1:
        raise ValueError("`window` must be at least 1.")
    if window > arr.shape[axis]:
        raise ValueError("`window` is too long.")
    y = nans(arr.shape)
    idx1 = [slice(None)] * arr.ndim
    idx2 = list(idx1)
    for i in range(window - 1, arr.shape[axis]):
        idx1[axis] = slice(i + 1 - window, i + 1)
        idx2[axis] = i
        y[idx2] = func(arr[idx1], axis=axis, **kwargs)
    return y
Beispiel #10
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 def test_nans_1(self):
     "afunc.nans_1"
     shape = (2,)
     actual = nans(shape)    
     desired = np.array([nan, nan])
     assert_almost_equal(actual, desired) 
Beispiel #11
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def lastrank(x, axis=-1, decay=0.0):
    """
    The ranking of the last element along the axis, ignoring NaNs.
    
    The ranking is normalized to be between -1 and 1 instead of the more
    common 1 and N. The results are adjusted for ties. Suitably slicing
    the output of the `ranking` method will give the same result as
    `lastrank`. The only difference is that `lastrank` is faster.       

    Parameters
    ----------
    x : numpy array
        The array to rank.
    axis : int, optional
        The axis over which to rank. By default (axis=-1) the ranking
        (and reducing) is performed over the last axis.          
    decay : scalar, optional
        Exponential decay strength. Cannot be negative. The default
        (decay=0) is no decay. In normal ranking (decay=0) all elements
        used to calculate the rank are equally weighted and so the
        ordering of all but the last element does not matter. In
        exponentially decayed ranking the ordering of the elements
        influences the ranking: elements nearer the last element get more
        weight.
        
    Returns
    -------
    d : array
        In the case of, for example, a 2d array of shape (n, m) and
        axis=1, the output will contain the rank (normalized to be between
        -1 and 1 and adjusted for ties) of the the last element of each row.
        The output in this example will have shape (n,). 
            
    Examples
    -------- 
    Create an array:
                    
    >>> y1 = larry([1, 2, 3])
    
    What is the rank of the last element (the value 3 in this example)?
    It is the largest element so the rank is 1.0:
    
    >>> import numpy as np
    >>> from la.afunc import lastrank
    >>> x1 = np.array([1, 2, 3])
    >>> lastrank(x1)
    1.0
    
    Now let's try an example where the last element has the smallest
    value:
    
    >>> x2 = np.array([3, 2, 1])
    >>> lastrank(x2)
    -1.0
    
    Here's an example where the last element is not the minimum or maximum
    value:
    
    >>> x3 = np.array([1, 3, 4, 5, 2])
    >>> lastrank(x3)
    -0.5
    
    Finally, let's add a large decay. The decay means that the elements
    closest to the last element receive the most weight. Because the
    decay is large, the first element (the value 1) doesn't get any weight
    and therefore the last element (2) becomes the smallest element:
    
    >>> lastrank(x3, decay=10)
    -1.0
    
    """
    if x.size == 0:
        # At least one dimension has length 0
        shape = list(x.shape)
        shape.pop(axis)
        r = nans(shape, dtype=x.dtype) 
        if (r.ndim == 0) and (r.size == 1):
            r = np.nan     
        return r 
    indlast = [slice(None)] * x.ndim 
    indlast[axis] = slice(-1, None)
    indlast2 = [slice(None)] * x.ndim 
    indlast2[axis] = -1  
    if decay > 0:
        # Exponential decay 
        nt = x.shape[axis]
        w = nt - np.ones(nt).cumsum()
        w = np.exp(-decay * w)
        w = nt * w / w.sum()
        matchdim = [None] * x.ndim 
        matchdim[axis] = slice(None)
        w = w[matchdim]
        g = ((x[indlast] > x) * w).sum(axis)
        e = ((x[indlast] == x) * w).sum(axis)
        n = (np.isfinite(x) * w).sum(axis)
        r = (g + g + e - w.flat[-1]) / 2.0
        r = r / (n - w.flat[-1])
    elif decay < 0:
        raise ValueError('decay must be greater than or equal to zero.')
    else:
        # Special case the most common case, decay = 0, for speed
        g = (x[indlast] > x).sum(axis)
        e = (x[indlast] == x).sum(axis)
        n = np.isfinite(x).sum(axis)
        r = (g + g + e - 1.0) / 2.0
        r = r / (n - 1.0)      
    r = 2.0 * (r - 0.5)    
    if x.ndim == 1:
        if not np.isfinite(x[indlast2]):
            r = np.nan
    else:
        np.putmask(r, ~np.isfinite(x[indlast2]), np.nan)
    return r    
Beispiel #12
0
def lastrank(x, axis=-1, decay=0.0):
    """
    The ranking of the last element along the axis, ignoring NaNs.
    
    The ranking is normalized to be between -1 and 1 instead of the more
    common 1 and N. The results are adjusted for ties. Suitably slicing
    the output of the `ranking` method will give the same result as
    `lastrank`. The only difference is that `lastrank` is faster.       

    Parameters
    ----------
    x : numpy array
        The array to rank.
    axis : int, optional
        The axis over which to rank. By default (axis=-1) the ranking
        (and reducing) is performed over the last axis.          
    decay : scalar, optional
        Exponential decay strength. Cannot be negative. The default
        (decay=0) is no decay. In normal ranking (decay=0) all elements
        used to calculate the rank are equally weighted and so the
        ordering of all but the last element does not matter. In
        exponentially decayed ranking the ordering of the elements
        influences the ranking: elements nearer the last element get more
        weight.
        
    Returns
    -------
    d : array
        In the case of, for example, a 2d array of shape (n, m) and
        axis=1, the output will contain the rank (normalized to be between
        -1 and 1 and adjusted for ties) of the the last element of each row.
        The output in this example will have shape (n,). 
            
    Examples
    -------- 
    Create an array:
                    
    >>> y1 = larry([1, 2, 3])
    
    What is the rank of the last element (the value 3 in this example)?
    It is the largest element so the rank is 1.0:
    
    >>> import numpy as np
    >>> from la.afunc import lastrank
    >>> x1 = np.array([1, 2, 3])
    >>> lastrank(x1)
    1.0
    
    Now let's try an example where the last element has the smallest
    value:
    
    >>> x2 = np.array([3, 2, 1])
    >>> lastrank(x2)
    -1.0
    
    Here's an example where the last element is not the minimum or maximum
    value:
    
    >>> x3 = np.array([1, 3, 4, 5, 2])
    >>> lastrank(x3)
    -0.5
    
    Finally, let's add a large decay. The decay means that the elements
    closest to the last element receive the most weight. Because the
    decay is large, the first element (the value 1) doesn't get any weight
    and therefore the last element (2) becomes the smallest element:
    
    >>> lastrank(x3, decay=10)
    -1.0
    
    """
    if x.size == 0:
        # At least one dimension has length 0
        shape = list(x.shape)
        shape.pop(axis)
        r = nans(shape, dtype=x.dtype)
        if (r.ndim == 0) and (r.size == 1):
            r = np.nan
        return r
    indlast = [slice(None)] * x.ndim
    indlast[axis] = slice(-1, None)
    indlast2 = [slice(None)] * x.ndim
    indlast2[axis] = -1
    if decay > 0:
        # Exponential decay
        nt = x.shape[axis]
        w = nt - np.ones(nt).cumsum()
        w = np.exp(-decay * w)
        w = nt * w / w.sum()
        matchdim = [None] * x.ndim
        matchdim[axis] = slice(None)
        w = w[matchdim]
        g = ((x[indlast] > x) * w).sum(axis)
        e = ((x[indlast] == x) * w).sum(axis)
        n = (np.isfinite(x) * w).sum(axis)
        r = (g + g + e - w.flat[-1]) / 2.0
        r = r / (n - w.flat[-1])
    elif decay < 0:
        raise ValueError('decay must be greater than or equal to zero.')
    else:
        # Special case the most common case, decay = 0, for speed
        g = (x[indlast] > x).sum(axis)
        e = (x[indlast] == x).sum(axis)
        n = np.isfinite(x).sum(axis)
        r = (g + g + e - 1.0) / 2.0
        r = r / (n - 1.0)
    r = 2.0 * (r - 0.5)
    if x.ndim == 1:
        if not np.isfinite(x[indlast2]):
            r = np.nan
    else:
        np.putmask(r, ~np.isfinite(x[indlast2]), np.nan)
    return r