Contents

Dequantize

General

Dequantize operation converts a quantized (u8/s8/f8_e4m3/f8_e5m2) tensor to an f32 tensor. It supports both per-tensor and per-channel asymmetric linear de-quantization. Rounding mode is library-implementation defined. Zero points (zps in the attribute table) are not supported for f8_e4m3 and f8_e5m2 dequantization.

For per-tensor de-quantization:

\[\dst_{i} = round((\src_{i} - zps) \times scale)\]

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

\[dst_{\cdots,i,\cdots,\cdots} = (\src_{\cdots,i,\cdots,\cdots} - zps_i) \times scale_i, i \in {[0, ic-1]}\]

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

scales

Scalings applied on the src data.

f32

A f32 list (only contain one element if qtype is per_tensor )

Required

zps

Offset values that maps to float zero.

s64

A s64 list (only contain one element if qtype is per_tensor ). If omitted, zps values are assumed to be zero.

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

Outputs

Index

Argument Name

Required or Optional

0

dst

Required

Supported data types

Dequantize operation supports the following data type combinations.

Src

Dst

s8, u8, f8_e4m3, f8_e5m2

f32

Note

This operation is to support int8 quantization model.

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