DynamicQuantize#

DynamicQuantize operation converts a f32 tensor to a quantized (s8 or u8) tensor. It supports both per-tensor and per-channel asymmetric linear quantization. The target quantized data type is specified via the data type of dst logical tensor. Rounding mode is library-implementation defined.

For per-tensor quantization:

\[\dst_{i} = round(\src_{i} / scale + zp)\]

For per-channel quantization, taking channel axis = 1 as an example:

\[dst_{\cdots,i,\cdots,\cdots} = round(\src_{\cdots,i,\cdots,\cdots} / scale_i + zp_i), i \in {[0, ic-1]}\]

where \(ic\) is the number of channels.

Operation Attributes#

Attribute

Name

Description

Value Type
Supported

Values
Required or

Optional

qtype

Specifies which de-quantization type is used

string

per_tensor (default), per_channel

Optional

axis

Specifies dimension on which per-channel de-quantization is applied

s64

A s64 value in the range of [-r, r-1] where r = rank(src), 1 by default

Optional

Execution Arguments#

The inputs and outputs must be provided according to the below index order when constructing an operation.

Inputs#

Index

Argument Name

Required or Optional

0

src

Required

1

scales

Required

2

zps

Optional

@note scales is a f32 1D tensor to be applied to the quantization formula. For qtype = per-tensor, there should be only one element in the scales tensor. For qtype = per-channel, the element number should be equal to the element number of src tensor along the dimension axis.

@note zps is a 1D tensor with offset values that map to zero. For qtype = per-tensor, there should be only one element in the zps tensor. For qtype = per-channel, the element number should be equal to the element number of input tensor along the dimension axis. If not specified, the library can assume the operator is symmetric quantization and perform kernel optimization accordingly.

Outputs#

Index

Argument Name

Required or Optional

0

dst

Required

Supported Data Types#

DynamicQuantize operation supports the following data type combinations.

Src

Scales

Zps

Dst

f32

f32

s8, u8, s32

s8

f32

f32

s8, u8, s32

u8