def _compute_mini(data_input, shape):
"""
Use log and taylor to compute
arctanh has the feature: arctanh(-abs(x)) = -arctanh(abs(x))
"""
data_abs = topi.abs(data_input)
result_ln = _compute_log(data_abs)
result_taylor = _compute_taylor(data_abs)
data_abs = topi.cast(data_abs, "float16")
data_input = topi.cast(data_input, "float16")
result_taylor = topi.cast(result_taylor, "float16")
result_ln = topi.cast(result_ln, "float16")
# when |x| < 0.5 using taylor computing, and when 0.5<|x|<1 using log()
data_res = tvm.compute(shape,
lambda *i : akg.tvm.expr.Select(data_abs(*i) < dc.half_const("float16"),
result_taylor(*i),
result_ln(*i)),
name="le")
# arctanh has the feature: arctanh(-abs(x)) = -arctanh(abs(x))
data_res_neg = topi.multiply(data_res, dc.neg_one_const("float16"))
data_res = tvm.compute(shape,
lambda *i : akg.tvm.expr.Select(data_input(*i) < dc.zero_const("float16"),
data_res_neg(*i),
data_res(*i)),
name="neg")
return data_res
def _compute_log(data_input, target=utils.CCE):
"""atanh(x) value is 0.5*log((1+x)/(1-x))"""
data_1_sum_x = topi.add(data_input, dc.one_const(data_input.dtype))
data_sub_x = topi.multiply(data_input, dc.neg_one_const(data_input.dtype))
data_1_sub_x = topi.add(data_sub_x, dc.one_const(data_input.dtype))
data_x_mul = data_1_sum_x / data_1_sub_x
data_x_log = log(data_x_mul, target)
data_res = topi.multiply(data_x_log, dc.half_const(data_input.dtype))
return data_res
def _compute_log(data_input):
"""Atanh(x) = 0.5*log((1+x)/(1-x))"""
data_1_sum_x = topi.add(data_input, dc.one_const(data_input.dtype))
data_sub_x = topi.multiply(data_input, dc.neg_one_const(data_input.dtype))
data_1_sub_x = topi.add(data_sub_x, dc.one_const(data_input.dtype))
data_x_mul = data_1_sum_x / data_1_sub_x
data_x_log = log.log(data_x_mul)
data_res = topi.multiply(data_x_log, dc.half_const(data_input.dtype))
return data_res
def fake_quant_with_min_max_vars_per_channel_compute(input_data,
input_min,
input_max,
num_bits=8,
narrow_range=False):
"""fake_quant_with_min_max_vars_per_channel compute implemention"""
shape = get_shape(input_data.shape)
dtype = input_data.dtype
min_broadcast = akg.lang.ascend.broadcast(input_min, shape, dtype)
max_broadcast = akg.lang.ascend.broadcast(input_max, shape, dtype)
# get nudged_min and nudged_max by nudged_min_max_compute function
nudged_min_nudged_max = nudged_min_max_compute(min_broadcast,
max_broadcast, num_bits,
narrow_range)
# transform the input between nudged_max and nudged_min
clamped_tmp = topi.minimum(input_data, nudged_min_nudged_max[1])
clamped = topi.maximum(clamped_tmp, nudged_min_nudged_max[0])
# calculate the quantized and dequantized results
clamped_shifted = topi.subtract(clamped, nudged_min_nudged_max[0])
if product_is_mini():
clamped_shifted_div_scale = mul(clamped_shifted,
reciprocal(nudged_min_nudged_max[2]),
target=utils.CCE)
else:
clamped_shifted_div_scale = Divide(clamped_shifted,
nudged_min_nudged_max[2],
target=utils.CCE)
result_tmp = topi.add(clamped_shifted_div_scale, dc.half_const(dtype))
floor_result_tmp = akg.lang.ascend.floor(result_tmp)
if product_is_mini():
floor_result_tmp = topi.cast(floor_result_tmp, "float16")
floor_result_tmp = topi.cast(floor_result_tmp, "float32")
scale_product = topi.multiply(floor_result_tmp, nudged_min_nudged_max[2])
tmp_res = topi.add(scale_product, nudged_min_nudged_max[0])
# get bool_both_zero_value by bool_both_zero_compute function
bool_both_zero_value = bool_both_zero_compute(min_broadcast, max_broadcast)
res = topi.multiply(tmp_res, bool_both_zero_value)
return res
def nudged_min_max_compute(min_broadcast, max_broadcast, num_bits,
narrow_range):
"""
Calculate the maximum and minimum values of the quantization.
Notes:
Each channel scale[i] euqal to (max_broadcast[i] - min_broadcast[i]) / (quant_max - quant_min).
Then compute nudged_zero_point:
nudged_zero_point = floor(between_min_max_float + 0.5) + less_quant_min_float + more_quant_max_float,
between_min_max_float is first calculated by:
zero_point_from_min = (quant_min_float - min_broadcast) / scale,
then between_min_max_float = zero_point_from_min, which min_broadcast <= zero_point_from_min <= max_broadcast.
Besides, the value of less_quant_min_float is equal to quant_min or zero, zero_point_from_min < quant_min_float,
the value is quant_min, else is 0. The same as more_quant_max_float.
Finally according to scale and nudged_zero_point to compute nudged_min and nudged_max:
nudged_min = (quant_min - nudged_zero_point) * scale
nudged_max = (quant_max - nudged_zero_point) * scale
Args:
min_broadcast (tvm.tensor.Tensor): minimum value to be quantified for each channel.
max_broadcast (tvm.tensor.Tensor): maximum value to be quantified for each channel.
num_bits (int): num_bits is the bitwidth of the quantization, range [2,16].
narrow_range (bool): if True, for each channel, quantized into the quantization range [0, 2^num_bits - 1] else
quantized into the quantization range [1, 2^num_bits - 1].
Returns:
nudged_min (tvm.tensor.Tensor): The same type and shape as min_broadcast.
nudged_max (tvm.tensor.Tensor): The same type and shape as max_broadcast.
scale (tvm.tensor.Tensor): The same type and shape as max_broadcast.
"""
dtype = min_broadcast.dtype
quant_min = 1 if narrow_range else 0
quant_max = (2**num_bits) - 1
# because of need compute each channel, so quant_min and quant_max need to broadcast.
quant_min_float = topi.full(min_broadcast.shape, dtype,
tvm.const(quant_min, dtype))
quant_max_float = topi.full(min_broadcast.shape, dtype,
tvm.const(quant_max, dtype))
# caculate each channel max and min difference.
max_sub_min = topi.subtract(max_broadcast, min_broadcast)
quant_max_sub_quant_min = topi.subtract(quant_max_float, quant_min_float)
# compute scale = (max_broadcast - min_broadcast) / (quant_max - quant_min)
# and min_div_scale = min_broadcast / scale
if product_is_mini():
scale = mul(max_sub_min,
reciprocal(quant_max_sub_quant_min),
target=utils.CCE)
min_div_scale = Mul(min_broadcast, reciprocal(scale), target=utils.CCE)
else:
scale = Divide(max_sub_min, quant_max_sub_quant_min, target=utils.CCE)
min_div_scale = Divide(min_broadcast, scale, target=utils.CCE)
# zero_point_from_min = quant_min_float - min_broadcast / scale
zero_point_from_min = topi.subtract(quant_min_float, min_div_scale)
# if zero_point_from_min < quant_min_float, bool_less_quant_min_float = 1 else 0
bool_less_quant_min_float = less_compare_float32(zero_point_from_min,
quant_min_float)
# if quant_max_float < zero_point_from_min, bool_more_quant_max_float = 1 else 0
bool_more_quant_max_float = less_compare_float32(quant_max_float,
zero_point_from_min)
# according to above bool param to select effective value
less_quant_min_float = topi.multiply(quant_min_float,
bool_less_quant_min_float)
more_quant_max_float = topi.multiply(quant_max_float,
bool_more_quant_max_float)
# compute which num is not less than quant_min_float and not large than quant_max_float
tensor_one = topi.full(min_broadcast.shape, dtype, dc.one_const(dtype))
bool_not_less_quant_min_float = topi.subtract(tensor_one,
bool_less_quant_min_float)
bool_not_more_quant_max_float = topi.subtract(tensor_one,
bool_more_quant_max_float)
bool_between_min_max = topi.multiply(bool_not_less_quant_min_float,
bool_not_more_quant_max_float)
between_min_max_float = topi.multiply(zero_point_from_min,
bool_between_min_max)
# add 0.5 to num which min <= num <= max and then floor them.
between_min_max_add_half_one = topi.add(between_min_max_float,
dc.half_const(dtype))
between_min_max_round = akg.lang.ascend.floor(between_min_max_add_half_one)
if product_is_mini():
between_min_max_round = topi.cast(between_min_max_round, "float16")
between_min_max_round = topi.cast(between_min_max_round, "float32")
# calculate the maximum and minimum values of the quantization
nudged_zero_point_tmp = topi.add(less_quant_min_float,
more_quant_max_float)
nudged_zero_point = topi.add(nudged_zero_point_tmp, between_min_max_round)
nudged_min_tmp = topi.subtract(quant_min_float, nudged_zero_point)
nudged_max_tmp = topi.subtract(quant_max_float, nudged_zero_point)
nudged_min = topi.multiply(nudged_min_tmp, scale)
nudged_max = topi.multiply(nudged_max_tmp, scale)
res = [nudged_min, nudged_max, scale]
return res