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# pylint: disable=invalid-name, line-too-long, unused-variable, too-many-locals
"""Upsampling in python"""
import math
import numpy as np
from topi.util import nchw_pack_layout


def upsample_nearest(arr, scale):
    """ Populate the array by scale factor"""
    h, w = arr.shape
    out_h = int(round(h * scale[0]))
    out_w = int(round(w * scale[1]))
    out = np.empty((out_h, out_w))
    for y in range(out_h):
        for x in range(out_w):
            in_y = math.floor(y / scale[0])
            in_x = math.floor(x / scale[1])
            out[y, x] = arr[in_y, in_x]
    return out

def upsampling_python(data, scale, layout='NCHW'):
    """ Python version of scaling using nearest neighbour """

    ishape = data.shape
    if layout == 'NCHW':
        oshape = (ishape[0], ishape[1], int(round(ishape[2]*scale[0])),
                  int(round(ishape[3]*scale[1])))
        output_np = np.zeros(oshape, dtype=data.dtype)
        for b in range(oshape[0]):
            for c in range(oshape[1]):
                output_np[b, c, :, :] = upsample_nearest(data[b, c, :, :], scale)
        return output_np
    # NCHWinic
    if nchw_pack_layout(layout):
        oshape = (ishape[0], ishape[1], int(round(ishape[2]*scale[0])),
                  int(round(ishape[3]*scale[1])), ishape[4], ishape[5])
        output_np = np.zeros(oshape, dtype=data.dtype)
        for b in range(oshape[0]):
            for ib in range(oshape[4]):
                for c in range(oshape[1]):
                    for ic in range(oshape[5]):
                        output_np[b, c, :, :, ib, ic] = upsample_nearest(data[b, c, :, :, ib, ic], scale)
        return output_np

    if layout == 'NHWC':
        oshape = (ishape[0], int(round(ishape[1]*scale[0])),
                  int(round(ishape[2]*scale[1])), ishape[3])
        output_np = np.zeros(oshape, dtype=data.dtype)
        for b in range(oshape[0]):
            for c in range(oshape[3]):
                output_np[b, :, :, c] = upsample_nearest(data[b, :, :, c], scale)
        return output_np
    raise ValueError("not support this layout {} yet".format(layout))

def upsample3d_nearest(arr, scale):
    """ Populate the array by scale factor"""
    d, h, w = arr.shape
    out_d = int(round(d * scale[0]))
    out_h = int(round(h * scale[1]))
    out_w = int(round(w * scale[2]))
    out = np.empty((out_d, out_h, out_w))
    for z in range(out_d):
        for y in range(out_h):
            for x in range(out_w):
                in_z = math.floor(z / scale[0])
                in_y = math.floor(y / scale[1])
                in_x = math.floor(x / scale[2])
                out[z, y, x] = arr[in_z, in_y, in_x]
    return out

def upsampling3d_python(data, scale, layout='NCDHW'):
    """ Python version of 3D scaling using nearest neighbour """

    ishape = data.shape
    if layout == 'NCDHW':
        oshape = (ishape[0], ishape[1],
                  int(round(ishape[2]*scale[0])),
                  int(round(ishape[3]*scale[1])),
                  int(round(ishape[4]*scale[2])))
        output_np = np.zeros(oshape, dtype=data.dtype)
        for b in range(oshape[0]):
            for c in range(oshape[1]):
                output_np[b, c, :, :, :] = upsample3d_nearest(data[b, c, :, :, :], scale)
        return output_np
    if layout == 'NDHWC':
        oshape = (ishape[0],
                  int(round(ishape[1]*scale[0])),
                  int(round(ishape[2]*scale[1])),
                  int(round(ishape[3]*scale[2])), ishape[4])
        output_np = np.zeros(oshape, dtype=data.dtype)
        for b in range(oshape[0]):
            for c in range(oshape[4]):
                output_np[b, :, :, :, c] = upsample3d_nearest(data[b, :, :, :, c], scale)
        return output_np
    raise ValueError("not support this layout {} yet".format(layout))
