unpack_blobs.py

import numpy as np

# Python samples to recover the zero compressed W4 blobs

nbit=4
numel_per_int32 = 32//nbit
group_size=32

linear_nnz = np.fromfile("sparse_w4/linear_nnz_int16.bin", dtype=np.int16)
tiled_nnz = linear_nnz.reshape(896,16)


linear_scales = np.fromfile("sparse_w4/linear_scales_float16.bin", dtype=np.float16)
tiled_scales = linear_scales.reshape(896, 16, 16, 8)


linear_bitmap_pack = np.fromfile('sparse_w4/linear_bitmap_int32.bin', dtype=np.int32)
linear_bitmap_pack = np.expand_dims(linear_bitmap_pack, axis=-1)
linear_bitmap = np.zeros((linear_bitmap_pack.shape[0], 32), dtype=np.int32)
for i in range(0, 32):
    linear_bitmap[:, i] = ( linear_bitmap_pack[:, 0] >> (32 - 1 - i) ) & 0x1
tiled_bitmap = linear_bitmap.reshape(-1).reshape(896, 16, 16, 256)


linear_qweight_pack = np.fromfile('sparse_w4/linear_compressed_qweight_int32.bin', dtype=np.int32)
linear_qweight_pack = np.expand_dims(linear_qweight_pack, axis=-1)
linear_qweight = np.zeros((linear_qweight_pack.shape[0], numel_per_int32), dtype=np.int32)
for i in range(0, numel_per_int32):
    linear_qweight[:, i] = ( linear_qweight_pack[:, 0] >> (numel_per_int32 - 1 - i)*nbit ) & 0xF
tiled_qweight = linear_qweight.reshape(-1).reshape(896, 16, 16, 256)


linear_zeros_pack = np.fromfile('sparse_w4/linear_zeros_int32.bin', dtype=np.int32)
linear_zeros_pack = np.expand_dims(linear_zeros_pack, axis=-1)
linear_zeros = np.zeros((linear_zeros_pack.shape[0], numel_per_int32), dtype=np.int32)
for i in range(0, numel_per_int32):
    linear_zeros[:, i] = ( linear_zeros_pack[:, 0] >> (numel_per_int32 - 1 - i)*nbit ) & 0xF
tiled_zeros = linear_zeros.reshape(-1).reshape(896, 16, 16, 8)

# ------------------------------------------------------------
# Decompress the tile, recover the zero locations
zero_recovered_tiles = np.ones_like(tiled_qweight)*8 # zero is represented by value of 8
for r in range(0, tiled_qweight.shape[0]):
    for c in range(0, tiled_qweight.shape[1]):
        zero_removed_padded_tile = tiled_qweight[r, c]
        nnz=tiled_nnz[r, c]
        tile_values = zero_removed_padded_tile.reshape(-1)[0:nnz]
        nnz_indices = np.nonzero(tiled_bitmap[r, c])
        zero_recovered_tiles[r, c][nnz_indices] = tile_values

# ------------------------------------------------------------
# Simulate dequantization of 4-bit weight to floating value
dequantized_tiles = np.zeros_like(zero_recovered_tiles, dtype=np.float16)

zero_recovered_tiles = zero_recovered_tiles.astype(np.float16)
tiled_zeros = tiled_zeros.astype(np.float16)
tiled_scales = tiled_scales.astype(np.float16)
for i in range(0, zero_recovered_tiles.shape[-1], group_size):
    gid = i//group_size
    dequantized_tiles[:, :, :, i:i+group_size] = \
        ( zero_recovered_tiles[:, :, :, i:i+group_size] - \
          np.expand_dims(tiled_zeros[:, :, :, gid], axis=-1) ) * \
            np.expand_dims(tiled_scales[:, :, :, gid], axis=-1)

# ------------------------------------------------------------
# Check sparsity per tile 
def calc_sparsity(tensor):
    nnz = np.count_nonzero(tensor)
    rate = 1-(nnz/tensor.size)
    return rate, nnz

for tile_r in range(0, dequantized_tiles.shape[0]):
    for tile_c in range(0, dequantized_tiles.shape[1]):
        sparsity, nnz = calc_sparsity(dequantized_tiles[tile_r, tile_c])
        print(f"tile [{tile_r:4},{tile_c:4}], sparsity: {sparsity*100:4.1f}%, nnz: {nnz:5}")

print("end.")