TMDSEVM572X: Can I get the DataQ for each output value?

user6446474

Prodigy 110 points

Part Number: TMDSEVM572X

Processor SDK: 06_03_00_106

Hello, TI!

When I run the TIDL layer_output example, it will create "trace*.info" files including DataQ, maxValue and minValue.

Supposing the output is 1*64*64(chanel*height*width)，

(1) do the maxValue and minValue in the "info" files mean the maximum and minimum DataQ for the output matrix? And the "DataQ" term indicates the average value?

(2) can I get the DataQ for each element in the output matrix?

Thanks!

over 4 years ago

0 Paula Carrillo over 4 years ago

TI__Mastermind 40630 points

Hi, could you please attach the trace info?

thank you,

Paula

0 user6446474 over 4 years ago in reply to Paula Carrillo

Prodigy 110 points

dataQ: 6891
minValue: -14991
maxValue: 251755

Hello, Paula!

It is the output of a convolution layer without activation.

The output value in "trace*.bin" file of this layer ranges from 0 to 255(I guess the TIDL outputs in unsigned 8-bit format).

I need the output with negative value. This is why I hope to get DataQ for each element to transform the output.

Thank you, Paula!

0 user6446474 over 4 years ago in reply to Paula Carrillo

Prodigy 110 points

Hi, Paula.

Is there any solution?

0 Paula Carrillo over 4 years ago in reply to user6446474

TI__Mastermind 40630 points

Hi I have been out of office. please give me few days to come back to you.

thank you,

Paula

0 Paula Carrillo over 4 years ago in reply to Paula Carrillo

TI__Mastermind 40630 points

Hi, please take a look to this E2E thread:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/642684/be-applied-the-regression-model-on-tidl-library/2370081#2370081

0 user6446474 over 4 years ago in reply to Paula Carrillo

Prodigy 110 points

I'll read the thread.

Thank you, Paula!

0 user6446474 over 4 years ago in reply to Paula Carrillo

Prodigy 110 points

Hi, Paula.

According to the thread, dataQ is defined within struct sTIDL_DataParams_t in the "tidl_create_params.h" file.

And the comments in that file:

@param  dataQ
          Number of bits for fractional part if Quant Style is 1
          Q factor if Quant Style is 2
 @param  minValue
          Minimum value of 32-bit accumulator for all the values in
					that layer
 @param  maxValue
          Maximum value of 32-bit accumulator for all the values in
					that layer

Does it mean the "minValue" and "maxValue" only stand for the minimum and maximum value of the output represented in 32-bit?

The "dataQ" is the scale factor for every element in that layer. So there is no way to get a specific dataQ for one element. Am I right?

So how to get the negative output(like "minValue") with the positive "dataQ" and TIDL output? Add a bias layer after the convolution layer?

+1 Praveen Eppa1 over 4 years ago in reply to user6446474

TI__Genius 17580 points

Hi,

>> Does it mean the "minValue" and "maxValue" only stand for the minimum and maximum value of the output represented in 32-bit?

Yes, however these are not final output of the layer, the final output is 8-bit quantized with scaling factor. You can get this scaling factor by dividing "dataQ" with 256.

This "dataQ" is same for every element in the layer. Yes, here is no way to get a specific dataQ for one element.

>> So how to get the negative output(like "minValue") with the positive "dataQ" and TIDL output? Add a bias layer after the convolution layer?

You will get negative output if the final TIDL quantized output is negative and divide it by scale factor ( dataQ/256).

Thanks,

Praveen

+1 user6446474 over 4 years ago in reply to Praveen Eppa1

Prodigy 110 points

>>You will get negative output if the final TIDL quantized output is negative and divide it by scale factor ( dataQ/256).

I kept wondering why I got positive output from LayerOutput->Data() even if I read the data buffer with "signed char".

Fortunately, I find it related to the arm compiler configurations.

Just add -fsigned-char during compilation and I can get negative value from LayerOutput->Data().

Thank you, Praveen! Thank you, Paula!

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TMDSEVM572X: Can I get the DataQ for each output value?