Intel® oneAPI Deep Neural Network Developer Guide and Reference
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LayerNorm
General
LayerNorm performs a layer normalization operation on 
 tensor.
The layerNorm operation performs normalization from begin_norm_axis to last dimension of the data tensor. It is defined by the following formulas which is the same as Layer Normalization.
 
   where
 are optional scale and shift for a channel
 are mean and variance (see
 is a constant to improve numerical stability.
Mean and variance are computed at runtime or provided by a user. When mean and variance are computed at runtime, the following formulas are used:
,
.
Operation attributes
Attribute Name  |  
        Description  |  
        Value Type  |  
        Supported Values  |  
        Required or Optional  |  
       
|---|---|---|---|---|
Indicate whether to output mean and variance which can be later passed to backward op.  |  
        bool  |  
        false , true (default)  |  
        Optional  |  
       |
begin_norm_axis is used to indicate which axis to start layer normalization. The normalization is from begin_norm_axis to last dimension. Negative values means indexing from right to left. This op normalizes over the last dimension by default, e.g. C in TNC for 3D and LDNC for 4D.  |  
        s64  |  
        [-r,r-1],where r=rank(src). -1 is default  |  
        Optional  |  
       |
When set to True, this module has learnable per-element affine parameters.  |  
        bool  |  
        false , true (default)  |  
        Optional  |  
       |
The constant to improve numerical stability.  |  
        f32  |  
        Arbitrary positive f32 value, 1e-5 (default)  |  
        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  |  
        gamma  |  
        Optional  |  
       
2  |  
        beta  |  
        Optional  |  
       
Outputs
Index  |  
        Argument Name  |  
        Required or Optional  |  
       
|---|---|---|
0  |  
        dst  |  
        Required  |  
       
1  |  
        mean  |  
        Optional  |  
       
2  |  
        variance  |  
        Optional  |  
       
Supported data types
LayerNorm operation supports the following data type combinations.
Src / Dst  |  
        Gamma / Beta / Mean / Variance  |  
       
|---|---|
f32  |  
        f32  |  
       
bf16  |  
        f32, bf16  |  
       
f16  |  
        f32  |