Mercurial > hg > vamp-build-and-test
diff DEPENDENCIES/mingw32/Python27/Lib/site-packages/numpy/lib/arraypad.py @ 87:2a2c65a20a8b
Add Python libs and headers
author | Chris Cannam |
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date | Wed, 25 Feb 2015 14:05:22 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/DEPENDENCIES/mingw32/Python27/Lib/site-packages/numpy/lib/arraypad.py Wed Feb 25 14:05:22 2015 +0000 @@ -0,0 +1,1475 @@ +""" +The arraypad module contains a group of functions to pad values onto the edges +of an n-dimensional array. + +""" +from __future__ import division, absolute_import, print_function + +import numpy as np +from numpy.compat import long + + +__all__ = ['pad'] + + +############################################################################### +# Private utility functions. + + +def _arange_ndarray(arr, shape, axis, reverse=False): + """ + Create an ndarray of `shape` with increments along specified `axis` + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + shape : tuple of ints + Shape of desired array. Should be equivalent to `arr.shape` except + `shape[axis]` which may have any positive value. + axis : int + Axis to increment along. + reverse : bool + If False, increment in a positive fashion from 1 to `shape[axis]`, + inclusive. If True, the bounds are the same but the order reversed. + + Returns + ------- + padarr : ndarray + Output array sized to pad `arr` along `axis`, with linear range from + 1 to `shape[axis]` along specified `axis`. + + Notes + ----- + The range is deliberately 1-indexed for this specific use case. Think of + this algorithm as broadcasting `np.arange` to a single `axis` of an + arbitrarily shaped ndarray. + + """ + initshape = tuple(1 if i != axis else shape[axis] + for (i, x) in enumerate(arr.shape)) + if not reverse: + padarr = np.arange(1, shape[axis] + 1) + else: + padarr = np.arange(shape[axis], 0, -1) + padarr = padarr.reshape(initshape) + for i, dim in enumerate(shape): + if padarr.shape[i] != dim: + padarr = padarr.repeat(dim, axis=i) + return padarr + + +def _round_ifneeded(arr, dtype): + """ + Rounds arr inplace if destination dtype is integer. + + Parameters + ---------- + arr : ndarray + Input array. + dtype : dtype + The dtype of the destination array. + + """ + if np.issubdtype(dtype, np.integer): + arr.round(out=arr) + + +def _prepend_const(arr, pad_amt, val, axis=-1): + """ + Prepend constant `val` along `axis` of `arr`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + val : scalar + Constant value to use. For best results should be of type `arr.dtype`; + if not `arr.dtype` will be cast to `arr.dtype`. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` constant `val` prepended along `axis`. + + """ + if pad_amt == 0: + return arr + padshape = tuple(x if i != axis else pad_amt + for (i, x) in enumerate(arr.shape)) + if val == 0: + return np.concatenate((np.zeros(padshape, dtype=arr.dtype), arr), + axis=axis) + else: + return np.concatenate(((np.zeros(padshape) + val).astype(arr.dtype), + arr), axis=axis) + + +def _append_const(arr, pad_amt, val, axis=-1): + """ + Append constant `val` along `axis` of `arr`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + val : scalar + Constant value to use. For best results should be of type `arr.dtype`; + if not `arr.dtype` will be cast to `arr.dtype`. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` constant `val` appended along `axis`. + + """ + if pad_amt == 0: + return arr + padshape = tuple(x if i != axis else pad_amt + for (i, x) in enumerate(arr.shape)) + if val == 0: + return np.concatenate((arr, np.zeros(padshape, dtype=arr.dtype)), + axis=axis) + else: + return np.concatenate( + (arr, (np.zeros(padshape) + val).astype(arr.dtype)), axis=axis) + + +def _prepend_edge(arr, pad_amt, axis=-1): + """ + Prepend `pad_amt` to `arr` along `axis` by extending edge values. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, extended by `pad_amt` edge values appended along `axis`. + + """ + if pad_amt == 0: + return arr + + edge_slice = tuple(slice(None) if i != axis else 0 + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + edge_arr = arr[edge_slice].reshape(pad_singleton) + return np.concatenate((edge_arr.repeat(pad_amt, axis=axis), arr), + axis=axis) + + +def _append_edge(arr, pad_amt, axis=-1): + """ + Append `pad_amt` to `arr` along `axis` by extending edge values. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, extended by `pad_amt` edge values prepended along + `axis`. + + """ + if pad_amt == 0: + return arr + + edge_slice = tuple(slice(None) if i != axis else arr.shape[axis] - 1 + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + edge_arr = arr[edge_slice].reshape(pad_singleton) + return np.concatenate((arr, edge_arr.repeat(pad_amt, axis=axis)), + axis=axis) + + +def _prepend_ramp(arr, pad_amt, end, axis=-1): + """ + Prepend linear ramp along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + end : scalar + Constal value to use. For best results should be of type `arr.dtype`; + if not `arr.dtype` will be cast to `arr.dtype`. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values prepended along `axis`. The + prepended region ramps linearly from the edge value to `end`. + + """ + if pad_amt == 0: + return arr + + # Generate shape for final concatenated array + padshape = tuple(x if i != axis else pad_amt + for (i, x) in enumerate(arr.shape)) + + # Generate an n-dimensional array incrementing along `axis` + ramp_arr = _arange_ndarray(arr, padshape, axis, + reverse=True).astype(np.float64) + + # Appropriate slicing to extract n-dimensional edge along `axis` + edge_slice = tuple(slice(None) if i != axis else 0 + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract edge, reshape to original rank, and extend along `axis` + edge_pad = arr[edge_slice].reshape(pad_singleton).repeat(pad_amt, axis) + + # Linear ramp + slope = (end - edge_pad) / float(pad_amt) + ramp_arr = ramp_arr * slope + ramp_arr += edge_pad + _round_ifneeded(ramp_arr, arr.dtype) + + # Ramp values will most likely be float, cast them to the same type as arr + return np.concatenate((ramp_arr.astype(arr.dtype), arr), axis=axis) + + +def _append_ramp(arr, pad_amt, end, axis=-1): + """ + Append linear ramp along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + end : scalar + Constal value to use. For best results should be of type `arr.dtype`; + if not `arr.dtype` will be cast to `arr.dtype`. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + appended region ramps linearly from the edge value to `end`. + + """ + if pad_amt == 0: + return arr + + # Generate shape for final concatenated array + padshape = tuple(x if i != axis else pad_amt + for (i, x) in enumerate(arr.shape)) + + # Generate an n-dimensional array incrementing along `axis` + ramp_arr = _arange_ndarray(arr, padshape, axis, + reverse=False).astype(np.float64) + + # Slice a chunk from the edge to calculate stats on + edge_slice = tuple(slice(None) if i != axis else -1 + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract edge, reshape to original rank, and extend along `axis` + edge_pad = arr[edge_slice].reshape(pad_singleton).repeat(pad_amt, axis) + + # Linear ramp + slope = (end - edge_pad) / float(pad_amt) + ramp_arr = ramp_arr * slope + ramp_arr += edge_pad + _round_ifneeded(ramp_arr, arr.dtype) + + # Ramp values will most likely be float, cast them to the same type as arr + return np.concatenate((arr, ramp_arr.astype(arr.dtype)), axis=axis) + + +def _prepend_max(arr, pad_amt, num, axis=-1): + """ + Prepend `pad_amt` maximum values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + num : int + Depth into `arr` along `axis` to calculate maximum. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + prepended region is the maximum of the first `num` values along + `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _prepend_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + max_slice = tuple(slice(None) if i != axis else slice(num) + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate max, reshape to add singleton dimension back + max_chunk = arr[max_slice].max(axis=axis).reshape(pad_singleton) + + # Concatenate `arr` with `max_chunk`, extended along `axis` by `pad_amt` + return np.concatenate((max_chunk.repeat(pad_amt, axis=axis), arr), + axis=axis) + + +def _append_max(arr, pad_amt, num, axis=-1): + """ + Pad one `axis` of `arr` with the maximum of the last `num` elements. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + num : int + Depth into `arr` along `axis` to calculate maximum. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + appended region is the maximum of the final `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _append_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + end = arr.shape[axis] - 1 + if num is not None: + max_slice = tuple( + slice(None) if i != axis else slice(end, end - num, -1) + for (i, x) in enumerate(arr.shape)) + else: + max_slice = tuple(slice(None) for x in arr.shape) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate max, reshape to add singleton dimension back + max_chunk = arr[max_slice].max(axis=axis).reshape(pad_singleton) + + # Concatenate `arr` with `max_chunk`, extended along `axis` by `pad_amt` + return np.concatenate((arr, max_chunk.repeat(pad_amt, axis=axis)), + axis=axis) + + +def _prepend_mean(arr, pad_amt, num, axis=-1): + """ + Prepend `pad_amt` mean values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + num : int + Depth into `arr` along `axis` to calculate mean. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values prepended along `axis`. The + prepended region is the mean of the first `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _prepend_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + mean_slice = tuple(slice(None) if i != axis else slice(num) + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate mean, reshape to add singleton dimension back + mean_chunk = arr[mean_slice].mean(axis).reshape(pad_singleton) + _round_ifneeded(mean_chunk, arr.dtype) + + # Concatenate `arr` with `mean_chunk`, extended along `axis` by `pad_amt` + return np.concatenate((mean_chunk.repeat(pad_amt, axis).astype(arr.dtype), + arr), axis=axis) + + +def _append_mean(arr, pad_amt, num, axis=-1): + """ + Append `pad_amt` mean values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + num : int + Depth into `arr` along `axis` to calculate mean. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + appended region is the maximum of the final `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _append_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + end = arr.shape[axis] - 1 + if num is not None: + mean_slice = tuple( + slice(None) if i != axis else slice(end, end - num, -1) + for (i, x) in enumerate(arr.shape)) + else: + mean_slice = tuple(slice(None) for x in arr.shape) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate mean, reshape to add singleton dimension back + mean_chunk = arr[mean_slice].mean(axis=axis).reshape(pad_singleton) + _round_ifneeded(mean_chunk, arr.dtype) + + # Concatenate `arr` with `mean_chunk`, extended along `axis` by `pad_amt` + return np.concatenate( + (arr, mean_chunk.repeat(pad_amt, axis).astype(arr.dtype)), axis=axis) + + +def _prepend_med(arr, pad_amt, num, axis=-1): + """ + Prepend `pad_amt` median values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + num : int + Depth into `arr` along `axis` to calculate median. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values prepended along `axis`. The + prepended region is the median of the first `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _prepend_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + med_slice = tuple(slice(None) if i != axis else slice(num) + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate median, reshape to add singleton dimension back + med_chunk = np.median(arr[med_slice], axis=axis).reshape(pad_singleton) + _round_ifneeded(med_chunk, arr.dtype) + + # Concatenate `arr` with `med_chunk`, extended along `axis` by `pad_amt` + return np.concatenate( + (med_chunk.repeat(pad_amt, axis).astype(arr.dtype), arr), axis=axis) + + +def _append_med(arr, pad_amt, num, axis=-1): + """ + Append `pad_amt` median values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + num : int + Depth into `arr` along `axis` to calculate median. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + appended region is the median of the final `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _append_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + end = arr.shape[axis] - 1 + if num is not None: + med_slice = tuple( + slice(None) if i != axis else slice(end, end - num, -1) + for (i, x) in enumerate(arr.shape)) + else: + med_slice = tuple(slice(None) for x in arr.shape) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate median, reshape to add singleton dimension back + med_chunk = np.median(arr[med_slice], axis=axis).reshape(pad_singleton) + _round_ifneeded(med_chunk, arr.dtype) + + # Concatenate `arr` with `med_chunk`, extended along `axis` by `pad_amt` + return np.concatenate( + (arr, med_chunk.repeat(pad_amt, axis).astype(arr.dtype)), axis=axis) + + +def _prepend_min(arr, pad_amt, num, axis=-1): + """ + Prepend `pad_amt` minimum values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to prepend. + num : int + Depth into `arr` along `axis` to calculate minimum. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values prepended along `axis`. The + prepended region is the minimum of the first `num` values along + `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _prepend_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + min_slice = tuple(slice(None) if i != axis else slice(num) + for (i, x) in enumerate(arr.shape)) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate min, reshape to add singleton dimension back + min_chunk = arr[min_slice].min(axis=axis).reshape(pad_singleton) + + # Concatenate `arr` with `min_chunk`, extended along `axis` by `pad_amt` + return np.concatenate((min_chunk.repeat(pad_amt, axis=axis), arr), + axis=axis) + + +def _append_min(arr, pad_amt, num, axis=-1): + """ + Append `pad_amt` median values along `axis`. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : int + Amount of padding to append. + num : int + Depth into `arr` along `axis` to calculate minimum. + Range: [1, `arr.shape[axis]`] or None (entire axis) + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt` values appended along `axis`. The + appended region is the minimum of the final `num` values along `axis`. + + """ + if pad_amt == 0: + return arr + + # Equivalent to edge padding for single value, so do that instead + if num == 1: + return _append_edge(arr, pad_amt, axis) + + # Use entire array if `num` is too large + if num is not None: + if num >= arr.shape[axis]: + num = None + + # Slice a chunk from the edge to calculate stats on + end = arr.shape[axis] - 1 + if num is not None: + min_slice = tuple( + slice(None) if i != axis else slice(end, end - num, -1) + for (i, x) in enumerate(arr.shape)) + else: + min_slice = tuple(slice(None) for x in arr.shape) + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + + # Extract slice, calculate min, reshape to add singleton dimension back + min_chunk = arr[min_slice].min(axis=axis).reshape(pad_singleton) + + # Concatenate `arr` with `min_chunk`, extended along `axis` by `pad_amt` + return np.concatenate((arr, min_chunk.repeat(pad_amt, axis=axis)), + axis=axis) + + +def _pad_ref(arr, pad_amt, method, axis=-1): + """ + Pad `axis` of `arr` by reflection. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : tuple of ints, length 2 + Padding to (prepend, append) along `axis`. + method : str + Controls method of reflection; options are 'even' or 'odd'. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt[0]` values prepended and `pad_amt[1]` + values appended along `axis`. Both regions are padded with reflected + values from the original array. + + Notes + ----- + This algorithm does not pad with repetition, i.e. the edges are not + repeated in the reflection. For that behavior, use `method='symmetric'`. + + The modes 'reflect', 'symmetric', and 'wrap' must be padded with a + single function, lest the indexing tricks in non-integer multiples of the + original shape would violate repetition in the final iteration. + + """ + # Implicit booleanness to test for zero (or None) in any scalar type + if pad_amt[0] == 0 and pad_amt[1] == 0: + return arr + + ########################################################################## + # Prepended region + + # Slice off a reverse indexed chunk from near edge to pad `arr` before + ref_slice = tuple(slice(None) if i != axis else slice(pad_amt[0], 0, -1) + for (i, x) in enumerate(arr.shape)) + + ref_chunk1 = arr[ref_slice] + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + if pad_amt[0] == 1: + ref_chunk1 = ref_chunk1.reshape(pad_singleton) + + # Memory/computationally more expensive, only do this if `method='odd'` + if 'odd' in method and pad_amt[0] > 0: + edge_slice1 = tuple(slice(None) if i != axis else 0 + for (i, x) in enumerate(arr.shape)) + edge_chunk = arr[edge_slice1].reshape(pad_singleton) + ref_chunk1 = 2 * edge_chunk - ref_chunk1 + del edge_chunk + + ########################################################################## + # Appended region + + # Slice off a reverse indexed chunk from far edge to pad `arr` after + start = arr.shape[axis] - pad_amt[1] - 1 + end = arr.shape[axis] - 1 + ref_slice = tuple(slice(None) if i != axis else slice(start, end) + for (i, x) in enumerate(arr.shape)) + rev_idx = tuple(slice(None) if i != axis else slice(None, None, -1) + for (i, x) in enumerate(arr.shape)) + ref_chunk2 = arr[ref_slice][rev_idx] + + if pad_amt[1] == 1: + ref_chunk2 = ref_chunk2.reshape(pad_singleton) + + if 'odd' in method: + edge_slice2 = tuple(slice(None) if i != axis else -1 + for (i, x) in enumerate(arr.shape)) + edge_chunk = arr[edge_slice2].reshape(pad_singleton) + ref_chunk2 = 2 * edge_chunk - ref_chunk2 + del edge_chunk + + # Concatenate `arr` with both chunks, extending along `axis` + return np.concatenate((ref_chunk1, arr, ref_chunk2), axis=axis) + + +def _pad_sym(arr, pad_amt, method, axis=-1): + """ + Pad `axis` of `arr` by symmetry. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : tuple of ints, length 2 + Padding to (prepend, append) along `axis`. + method : str + Controls method of symmetry; options are 'even' or 'odd'. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt[0]` values prepended and `pad_amt[1]` + values appended along `axis`. Both regions are padded with symmetric + values from the original array. + + Notes + ----- + This algorithm DOES pad with repetition, i.e. the edges are repeated. + For a method that does not repeat edges, use `method='reflect'`. + + The modes 'reflect', 'symmetric', and 'wrap' must be padded with a + single function, lest the indexing tricks in non-integer multiples of the + original shape would violate repetition in the final iteration. + + """ + # Implicit booleanness to test for zero (or None) in any scalar type + if pad_amt[0] == 0 and pad_amt[1] == 0: + return arr + + ########################################################################## + # Prepended region + + # Slice off a reverse indexed chunk from near edge to pad `arr` before + sym_slice = tuple(slice(None) if i != axis else slice(0, pad_amt[0]) + for (i, x) in enumerate(arr.shape)) + rev_idx = tuple(slice(None) if i != axis else slice(None, None, -1) + for (i, x) in enumerate(arr.shape)) + sym_chunk1 = arr[sym_slice][rev_idx] + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + if pad_amt[0] == 1: + sym_chunk1 = sym_chunk1.reshape(pad_singleton) + + # Memory/computationally more expensive, only do this if `method='odd'` + if 'odd' in method and pad_amt[0] > 0: + edge_slice1 = tuple(slice(None) if i != axis else 0 + for (i, x) in enumerate(arr.shape)) + edge_chunk = arr[edge_slice1].reshape(pad_singleton) + sym_chunk1 = 2 * edge_chunk - sym_chunk1 + del edge_chunk + + ########################################################################## + # Appended region + + # Slice off a reverse indexed chunk from far edge to pad `arr` after + start = arr.shape[axis] - pad_amt[1] + end = arr.shape[axis] + sym_slice = tuple(slice(None) if i != axis else slice(start, end) + for (i, x) in enumerate(arr.shape)) + sym_chunk2 = arr[sym_slice][rev_idx] + + if pad_amt[1] == 1: + sym_chunk2 = sym_chunk2.reshape(pad_singleton) + + if 'odd' in method: + edge_slice2 = tuple(slice(None) if i != axis else -1 + for (i, x) in enumerate(arr.shape)) + edge_chunk = arr[edge_slice2].reshape(pad_singleton) + sym_chunk2 = 2 * edge_chunk - sym_chunk2 + del edge_chunk + + # Concatenate `arr` with both chunks, extending along `axis` + return np.concatenate((sym_chunk1, arr, sym_chunk2), axis=axis) + + +def _pad_wrap(arr, pad_amt, axis=-1): + """ + Pad `axis` of `arr` via wrapping. + + Parameters + ---------- + arr : ndarray + Input array of arbitrary shape. + pad_amt : tuple of ints, length 2 + Padding to (prepend, append) along `axis`. + axis : int + Axis along which to pad `arr`. + + Returns + ------- + padarr : ndarray + Output array, with `pad_amt[0]` values prepended and `pad_amt[1]` + values appended along `axis`. Both regions are padded wrapped values + from the opposite end of `axis`. + + Notes + ----- + This method of padding is also known as 'tile' or 'tiling'. + + The modes 'reflect', 'symmetric', and 'wrap' must be padded with a + single function, lest the indexing tricks in non-integer multiples of the + original shape would violate repetition in the final iteration. + + """ + # Implicit booleanness to test for zero (or None) in any scalar type + if pad_amt[0] == 0 and pad_amt[1] == 0: + return arr + + ########################################################################## + # Prepended region + + # Slice off a reverse indexed chunk from near edge to pad `arr` before + start = arr.shape[axis] - pad_amt[0] + end = arr.shape[axis] + wrap_slice = tuple(slice(None) if i != axis else slice(start, end) + for (i, x) in enumerate(arr.shape)) + wrap_chunk1 = arr[wrap_slice] + + # Shape to restore singleton dimension after slicing + pad_singleton = tuple(x if i != axis else 1 + for (i, x) in enumerate(arr.shape)) + if pad_amt[0] == 1: + wrap_chunk1 = wrap_chunk1.reshape(pad_singleton) + + ########################################################################## + # Appended region + + # Slice off a reverse indexed chunk from far edge to pad `arr` after + wrap_slice = tuple(slice(None) if i != axis else slice(0, pad_amt[1]) + for (i, x) in enumerate(arr.shape)) + wrap_chunk2 = arr[wrap_slice] + + if pad_amt[1] == 1: + wrap_chunk2 = wrap_chunk2.reshape(pad_singleton) + + # Concatenate `arr` with both chunks, extending along `axis` + return np.concatenate((wrap_chunk1, arr, wrap_chunk2), axis=axis) + + +def _normalize_shape(narray, shape): + """ + Private function which does some checks and normalizes the possibly + much simpler representations of 'pad_width', 'stat_length', + 'constant_values', 'end_values'. + + Parameters + ---------- + narray : ndarray + Input ndarray + shape : {sequence, int}, optional + The width of padding (pad_width) or the number of elements on the + edge of the narray used for statistics (stat_length). + ((before_1, after_1), ... (before_N, after_N)) unique number of + elements for each axis where `N` is rank of `narray`. + ((before, after),) yields same before and after constants for each + axis. + (constant,) or int is a shortcut for before = after = constant for + all axes. + + Returns + ------- + _normalize_shape : tuple of tuples + int => ((int, int), (int, int), ...) + [[int1, int2], [int3, int4], ...] => ((int1, int2), (int3, int4), ...) + ((int1, int2), (int3, int4), ...) => no change + [[int1, int2], ] => ((int1, int2), (int1, int2), ...) + ((int1, int2), ) => ((int1, int2), (int1, int2), ...) + [[int , ], ] => ((int, int), (int, int), ...) + ((int , ), ) => ((int, int), (int, int), ...) + + """ + normshp = None + shapelen = len(np.shape(narray)) + if (isinstance(shape, int)) or shape is None: + normshp = ((shape, shape), ) * shapelen + elif (isinstance(shape, (tuple, list)) + and isinstance(shape[0], (tuple, list)) + and len(shape) == shapelen): + normshp = shape + for i in normshp: + if len(i) != 2: + fmt = "Unable to create correctly shaped tuple from %s" + raise ValueError(fmt % (normshp,)) + elif (isinstance(shape, (tuple, list)) + and isinstance(shape[0], (int, float, long)) + and len(shape) == 1): + normshp = ((shape[0], shape[0]), ) * shapelen + elif (isinstance(shape, (tuple, list)) + and isinstance(shape[0], (int, float, long)) + and len(shape) == 2): + normshp = (shape, ) * shapelen + if normshp is None: + fmt = "Unable to create correctly shaped tuple from %s" + raise ValueError(fmt % (shape,)) + return normshp + + +def _validate_lengths(narray, number_elements): + """ + Private function which does some checks and reformats pad_width and + stat_length using _normalize_shape. + + Parameters + ---------- + narray : ndarray + Input ndarray + number_elements : {sequence, int}, optional + The width of padding (pad_width) or the number of elements on the edge + of the narray used for statistics (stat_length). + ((before_1, after_1), ... (before_N, after_N)) unique number of + elements for each axis. + ((before, after),) yields same before and after constants for each + axis. + (constant,) or int is a shortcut for before = after = constant for all + axes. + + Returns + ------- + _validate_lengths : tuple of tuples + int => ((int, int), (int, int), ...) + [[int1, int2], [int3, int4], ...] => ((int1, int2), (int3, int4), ...) + ((int1, int2), (int3, int4), ...) => no change + [[int1, int2], ] => ((int1, int2), (int1, int2), ...) + ((int1, int2), ) => ((int1, int2), (int1, int2), ...) + [[int , ], ] => ((int, int), (int, int), ...) + ((int , ), ) => ((int, int), (int, int), ...) + + """ + normshp = _normalize_shape(narray, number_elements) + for i in normshp: + chk = [1 if x is None else x for x in i] + chk = [1 if x >= 0 else -1 for x in chk] + if (chk[0] < 0) or (chk[1] < 0): + fmt = "%s cannot contain negative values." + raise ValueError(fmt % (number_elements,)) + return normshp + + +############################################################################### +# Public functions + + +def pad(array, pad_width, mode=None, **kwargs): + """ + Pads an array. + + Parameters + ---------- + array : array_like of rank N + Input array + pad_width : {sequence, int} + Number of values padded to the edges of each axis. + ((before_1, after_1), ... (before_N, after_N)) unique pad widths + for each axis. + ((before, after),) yields same before and after pad for each axis. + (pad,) or int is a shortcut for before = after = pad width for all + axes. + mode : {str, function} + One of the following string values or a user supplied function. + + 'constant' + Pads with a constant value. + 'edge' + Pads with the edge values of array. + 'linear_ramp' + Pads with the linear ramp between end_value and the + array edge value. + 'maximum' + Pads with the maximum value of all or part of the + vector along each axis. + 'mean' + Pads with the mean value of all or part of the + vector along each axis. + 'median' + Pads with the median value of all or part of the + vector along each axis. + 'minimum' + Pads with the minimum value of all or part of the + vector along each axis. + 'reflect' + Pads with the reflection of the vector mirrored on + the first and last values of the vector along each + axis. + 'symmetric' + Pads with the reflection of the vector mirrored + along the edge of the array. + 'wrap' + Pads with the wrap of the vector along the axis. + The first values are used to pad the end and the + end values are used to pad the beginning. + <function> + Padding function, see Notes. + stat_length : {sequence, int}, optional + Used in 'maximum', 'mean', 'median', and 'minimum'. Number of + values at edge of each axis used to calculate the statistic value. + + ((before_1, after_1), ... (before_N, after_N)) unique statistic + lengths for each axis. + + ((before, after),) yields same before and after statistic lengths + for each axis. + + (stat_length,) or int is a shortcut for before = after = statistic + length for all axes. + + Default is ``None``, to use the entire axis. + constant_values : {sequence, int}, optional + Used in 'constant'. The values to set the padded values for each + axis. + + ((before_1, after_1), ... (before_N, after_N)) unique pad constants + for each axis. + + ((before, after),) yields same before and after constants for each + axis. + + (constant,) or int is a shortcut for before = after = constant for + all axes. + + Default is 0. + end_values : {sequence, int}, optional + Used in 'linear_ramp'. The values used for the ending value of the + linear_ramp and that will form the edge of the padded array. + + ((before_1, after_1), ... (before_N, after_N)) unique end values + for each axis. + + ((before, after),) yields same before and after end values for each + axis. + + (constant,) or int is a shortcut for before = after = end value for + all axes. + + Default is 0. + reflect_type : str {'even', 'odd'}, optional + Used in 'reflect', and 'symmetric'. The 'even' style is the + default with an unaltered reflection around the edge value. For + the 'odd' style, the extented part of the array is created by + subtracting the reflected values from two times the edge value. + + Returns + ------- + pad : ndarray + Padded array of rank equal to `array` with shape increased + according to `pad_width`. + + Notes + ----- + .. versionadded:: 1.7.0 + + For an array with rank greater than 1, some of the padding of later + axes is calculated from padding of previous axes. This is easiest to + think about with a rank 2 array where the corners of the padded array + are calculated by using padded values from the first axis. + + The padding function, if used, should return a rank 1 array equal in + length to the vector argument with padded values replaced. It has the + following signature:: + + padding_func(vector, iaxis_pad_width, iaxis, **kwargs) + + where + + vector : ndarray + A rank 1 array already padded with zeros. Padded values are + vector[:pad_tuple[0]] and vector[-pad_tuple[1]:]. + iaxis_pad_width : tuple + A 2-tuple of ints, iaxis_pad_width[0] represents the number of + values padded at the beginning of vector where + iaxis_pad_width[1] represents the number of values padded at + the end of vector. + iaxis : int + The axis currently being calculated. + kwargs : misc + Any keyword arguments the function requires. + + Examples + -------- + >>> a = [1, 2, 3, 4, 5] + >>> np.lib.pad(a, (2,3), 'constant', constant_values=(4,6)) + array([4, 4, 1, 2, 3, 4, 5, 6, 6, 6]) + + >>> np.lib.pad(a, (2,3), 'edge') + array([1, 1, 1, 2, 3, 4, 5, 5, 5, 5]) + + >>> np.lib.pad(a, (2,3), 'linear_ramp', end_values=(5,-4)) + array([ 5, 3, 1, 2, 3, 4, 5, 2, -1, -4]) + + >>> np.lib.pad(a, (2,), 'maximum') + array([5, 5, 1, 2, 3, 4, 5, 5, 5]) + + >>> np.lib.pad(a, (2,), 'mean') + array([3, 3, 1, 2, 3, 4, 5, 3, 3]) + + >>> np.lib.pad(a, (2,), 'median') + array([3, 3, 1, 2, 3, 4, 5, 3, 3]) + + >>> a = [[1,2], [3,4]] + >>> np.lib.pad(a, ((3, 2), (2, 3)), 'minimum') + array([[1, 1, 1, 2, 1, 1, 1], + [1, 1, 1, 2, 1, 1, 1], + [1, 1, 1, 2, 1, 1, 1], + [1, 1, 1, 2, 1, 1, 1], + [3, 3, 3, 4, 3, 3, 3], + [1, 1, 1, 2, 1, 1, 1], + [1, 1, 1, 2, 1, 1, 1]]) + + >>> a = [1, 2, 3, 4, 5] + >>> np.lib.pad(a, (2,3), 'reflect') + array([3, 2, 1, 2, 3, 4, 5, 4, 3, 2]) + + >>> np.lib.pad(a, (2,3), 'reflect', reflect_type='odd') + array([-1, 0, 1, 2, 3, 4, 5, 6, 7, 8]) + + >>> np.lib.pad(a, (2,3), 'symmetric') + array([2, 1, 1, 2, 3, 4, 5, 5, 4, 3]) + + >>> np.lib.pad(a, (2,3), 'symmetric', reflect_type='odd') + array([0, 1, 1, 2, 3, 4, 5, 5, 6, 7]) + + >>> np.lib.pad(a, (2,3), 'wrap') + array([4, 5, 1, 2, 3, 4, 5, 1, 2, 3]) + + >>> def padwithtens(vector, pad_width, iaxis, kwargs): + ... vector[:pad_width[0]] = 10 + ... vector[-pad_width[1]:] = 10 + ... return vector + + >>> a = np.arange(6) + >>> a = a.reshape((2,3)) + + >>> np.lib.pad(a, 2, padwithtens) + array([[10, 10, 10, 10, 10, 10, 10], + [10, 10, 10, 10, 10, 10, 10], + [10, 10, 0, 1, 2, 10, 10], + [10, 10, 3, 4, 5, 10, 10], + [10, 10, 10, 10, 10, 10, 10], + [10, 10, 10, 10, 10, 10, 10]]) + """ + + narray = np.array(array) + pad_width = _validate_lengths(narray, pad_width) + + allowedkwargs = { + 'constant': ['constant_values'], + 'edge': [], + 'linear_ramp': ['end_values'], + 'maximum': ['stat_length'], + 'mean': ['stat_length'], + 'median': ['stat_length'], + 'minimum': ['stat_length'], + 'reflect': ['reflect_type'], + 'symmetric': ['reflect_type'], + 'wrap': [], + } + + kwdefaults = { + 'stat_length': None, + 'constant_values': 0, + 'end_values': 0, + 'reflect_type': 'even', + } + + if isinstance(mode, str): + # Make sure have allowed kwargs appropriate for mode + for key in kwargs: + if key not in allowedkwargs[mode]: + raise ValueError('%s keyword not in allowed keywords %s' % + (key, allowedkwargs[mode])) + + # Set kwarg defaults + for kw in allowedkwargs[mode]: + kwargs.setdefault(kw, kwdefaults[kw]) + + # Need to only normalize particular keywords. + for i in kwargs: + if i == 'stat_length': + kwargs[i] = _validate_lengths(narray, kwargs[i]) + if i in ['end_values', 'constant_values']: + kwargs[i] = _normalize_shape(narray, kwargs[i]) + elif mode is None: + raise ValueError('Keyword "mode" must be a function or one of %s.' % + (list(allowedkwargs.keys()),)) + else: + # Drop back to old, slower np.apply_along_axis mode for user-supplied + # vector function + function = mode + + # Create a new padded array + rank = list(range(len(narray.shape))) + total_dim_increase = [np.sum(pad_width[i]) for i in rank] + offset_slices = [slice(pad_width[i][0], + pad_width[i][0] + narray.shape[i]) + for i in rank] + new_shape = np.array(narray.shape) + total_dim_increase + newmat = np.zeros(new_shape, narray.dtype) + + # Insert the original array into the padded array + newmat[offset_slices] = narray + + # This is the core of pad ... + for iaxis in rank: + np.apply_along_axis(function, + iaxis, + newmat, + pad_width[iaxis], + iaxis, + kwargs) + return newmat + + # If we get here, use new padding method + newmat = narray.copy() + + # API preserved, but completely new algorithm which pads by building the + # entire block to pad before/after `arr` with in one step, for each axis. + if mode == 'constant': + for axis, ((pad_before, pad_after), (before_val, after_val)) \ + in enumerate(zip(pad_width, kwargs['constant_values'])): + newmat = _prepend_const(newmat, pad_before, before_val, axis) + newmat = _append_const(newmat, pad_after, after_val, axis) + + elif mode == 'edge': + for axis, (pad_before, pad_after) in enumerate(pad_width): + newmat = _prepend_edge(newmat, pad_before, axis) + newmat = _append_edge(newmat, pad_after, axis) + + elif mode == 'linear_ramp': + for axis, ((pad_before, pad_after), (before_val, after_val)) \ + in enumerate(zip(pad_width, kwargs['end_values'])): + newmat = _prepend_ramp(newmat, pad_before, before_val, axis) + newmat = _append_ramp(newmat, pad_after, after_val, axis) + + elif mode == 'maximum': + for axis, ((pad_before, pad_after), (chunk_before, chunk_after)) \ + in enumerate(zip(pad_width, kwargs['stat_length'])): + newmat = _prepend_max(newmat, pad_before, chunk_before, axis) + newmat = _append_max(newmat, pad_after, chunk_after, axis) + + elif mode == 'mean': + for axis, ((pad_before, pad_after), (chunk_before, chunk_after)) \ + in enumerate(zip(pad_width, kwargs['stat_length'])): + newmat = _prepend_mean(newmat, pad_before, chunk_before, axis) + newmat = _append_mean(newmat, pad_after, chunk_after, axis) + + elif mode == 'median': + for axis, ((pad_before, pad_after), (chunk_before, chunk_after)) \ + in enumerate(zip(pad_width, kwargs['stat_length'])): + newmat = _prepend_med(newmat, pad_before, chunk_before, axis) + newmat = _append_med(newmat, pad_after, chunk_after, axis) + + elif mode == 'minimum': + for axis, ((pad_before, pad_after), (chunk_before, chunk_after)) \ + in enumerate(zip(pad_width, kwargs['stat_length'])): + newmat = _prepend_min(newmat, pad_before, chunk_before, axis) + newmat = _append_min(newmat, pad_after, chunk_after, axis) + + elif mode == 'reflect': + for axis, (pad_before, pad_after) in enumerate(pad_width): + # Recursive padding along any axis where `pad_amt` is too large + # for indexing tricks. We can only safely pad the original axis + # length, to keep the period of the reflections consistent. + if ((pad_before > 0) or + (pad_after > 0)) and newmat.shape[axis] == 1: + # Extending singleton dimension for 'reflect' is legacy + # behavior; it really should raise an error. + newmat = _prepend_edge(newmat, pad_before, axis) + newmat = _append_edge(newmat, pad_after, axis) + continue + + method = kwargs['reflect_type'] + safe_pad = newmat.shape[axis] - 1 + while ((pad_before > safe_pad) or (pad_after > safe_pad)): + offset = 0 + pad_iter_b = min(safe_pad, + safe_pad * (pad_before // safe_pad)) + pad_iter_a = min(safe_pad, safe_pad * (pad_after // safe_pad)) + newmat = _pad_ref(newmat, (pad_iter_b, + pad_iter_a), method, axis) + pad_before -= pad_iter_b + pad_after -= pad_iter_a + if pad_iter_b > 0: + offset += 1 + if pad_iter_a > 0: + offset += 1 + safe_pad += pad_iter_b + pad_iter_a + newmat = _pad_ref(newmat, (pad_before, pad_after), method, axis) + + elif mode == 'symmetric': + for axis, (pad_before, pad_after) in enumerate(pad_width): + # Recursive padding along any axis where `pad_amt` is too large + # for indexing tricks. We can only safely pad the original axis + # length, to keep the period of the reflections consistent. + method = kwargs['reflect_type'] + safe_pad = newmat.shape[axis] + while ((pad_before > safe_pad) or + (pad_after > safe_pad)): + pad_iter_b = min(safe_pad, + safe_pad * (pad_before // safe_pad)) + pad_iter_a = min(safe_pad, safe_pad * (pad_after // safe_pad)) + newmat = _pad_sym(newmat, (pad_iter_b, + pad_iter_a), method, axis) + pad_before -= pad_iter_b + pad_after -= pad_iter_a + safe_pad += pad_iter_b + pad_iter_a + newmat = _pad_sym(newmat, (pad_before, pad_after), method, axis) + + elif mode == 'wrap': + for axis, (pad_before, pad_after) in enumerate(pad_width): + # Recursive padding along any axis where `pad_amt` is too large + # for indexing tricks. We can only safely pad the original axis + # length, to keep the period of the reflections consistent. + safe_pad = newmat.shape[axis] + while ((pad_before > safe_pad) or + (pad_after > safe_pad)): + pad_iter_b = min(safe_pad, + safe_pad * (pad_before // safe_pad)) + pad_iter_a = min(safe_pad, safe_pad * (pad_after // safe_pad)) + newmat = _pad_wrap(newmat, (pad_iter_b, pad_iter_a), axis) + + pad_before -= pad_iter_b + pad_after -= pad_iter_a + safe_pad += pad_iter_b + pad_iter_a + newmat = _pad_wrap(newmat, (pad_before, pad_after), axis) + + return newmat