DynamicDequantize¶

General¶

DynamicDequantize operation converts a quantized (s8 or u8) tensor to a f32 tensor. It supports both per-tensor and per-channel asymmetric linear de-quantization. Rounding mode is library-implementation defined. Unlike the Dequantize, DynamicDequantize takes scales and zero-points as operator src tensors.

For per-tensor de-quantization

$dst = (src - zps)*scales$

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

${dst}_{\cdots,i,\cdots,\cdots} = (src_{\cdots,i,\cdots,\cdots} - zps_i)*scales_i,i\in [0,channelNum-1]$

Operation attributes¶

Attribute Name

De

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. Negative value means counting the dimension backwards from the end.

Optional

Execution arguments¶

The inputs and outputs must be provided according to 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 de-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 de-quantization and perform kernel optimization accordingly.

Outputs¶

Index

Argument Name

Required or Optional

0

dst

Required

Supported data types¶

DynamicDequantize operation supports the following data type combinations.

Src

Dst

Scales

Zps

s8

f32

f32

s8, u8, s32

u8

f32

f32

s8, u8, s32