customing a layer and error

After customizing the layer, I used the checkLayer function to check the validity of the layer. If the input is (H, W, C) and debugging, the input is expanded to (H, W, C, N). Can you tell me why this is so?

[Shubham Khatri]

It should error out on entering the third parameter as you have not specified its value in the fourth variable. Can you share the reporduction steps?

Answer 1

[Shubham Khatri]

Hello,

To my understanding the checklayer funtion accepts input in 2 ways.

2 inputs-

checkLayer(layer,validInputSize)

Checks the validity of a custom layer using generated data of the sizes in validInputSize. Variable validInputSize defines the number of inputs to the layer.

4 inputs-

checkLayer(layer,validInputSize,Name,Value)

The third input and fourth input are linked with each other. The third input defines the additional parameter for check and the fourth input defines the value of the third parameter to compare to.

Please refer to the documentation link for checklayer here

Hope it helps.

[JaeHyeon Lee]

I made the source code of the layer like this, and when debugging, I could see that the shape of X1, X2, X3 is changed to 4D-dlarray. Can I know specifically why?

The validity of the layer was checkedLayer(layer, {[28 28 128], [28 28 128], [28 28 128]},'ObservationDimension', 4).

classdef nonLocalBlock < nnet.layer.Layer
    properties (Learnable)
        % Layer learnable parameters
        % Scaling coefficients
    end
    
    methods
        function layer = nonLocalBlock(numInputs,name) 
            layer.NumInputs = numInputs;
            layer.Name = name;
            layer.Description = "Non-local Block" ;
        end
        
        function Z = predict(~, X1, X2, X3)    
            X1_size = size(X1);
            X2_size = size(X2);
            X3_size = size(X3);
            [H, W, C, D] = size(X1); 
            
            X1 = reshape(X1 ,H*W, C, 1, []);
            X2 = reshape(X2, C, H*W, 1, []);
            X3 = reshape(X3 ,H*W, C, 1, []);
            
            if D > 1
               f = pagemtimes(X1, X2);
            else
               f = mtimes(X1, X2);
            end
          
            f_div_C = softmax(f,'DataFormat','SSCB');
        
            if D > 1
               y = pagemtimes(f_div_C, X3);
            else
               y = mtimes(f_div_C, X3);
            end
            
            y = reshape(y, H, W, C, []);
            Z = y;
        end
    end
end