Matrix Multiplication

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karthiks
Posts: 78
Joined: Thu Sep 02, 2010 2:43 pm
Location: Université Libre de Bruxelles

Matrix Multiplication

Post by karthiks »

Hey,

I know that the signal acquired is in the form of a matrix. How can I multiply another matrix with it?
Regards,

Karthik

lbonnet
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Posts: 417
Joined: Wed Oct 07, 2009 12:11 pm

Re: Matrix Multiplication

Post by lbonnet »

Hi,

You can use a Simple DSP, with 2 input matrices.
Equation : A*B

Be sure to have synchronized input streams.

Hope this helps.

Laurent
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karthiks
Posts: 78
Joined: Thu Sep 02, 2010 2:43 pm
Location: Université Libre de Bruxelles

Re: Matrix Multiplication

Post by karthiks »

lbonnet wrote:Hi,

You can use a Simple DSP, with 2 input matrices.
Equation : A*B

Be sure to have synchronized input streams.

Hope this helps.

Laurent
I am trying to use a static matrix (one that I have) to multiply with the matrix from the signal.

Should I use the DSP box stil?
Regards,

Karthik

yrenard
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Re: Matrix Multiplication

Post by yrenard »

The Simple DSP does not multiply matrices.

karthiks, there is no general purpose matrix multiplication box as this is not really meaningful for the scenario author, this should probably be done at a lower level, by a developer.

Still, you can multiply a vector of samples by a matrix using the Spatial Filter box but this may not be what you want.

What is the purpose of that multiplication you want to achieve ?

Hope this helps,
Yann

karthiks
Posts: 78
Joined: Thu Sep 02, 2010 2:43 pm
Location: Université Libre de Bruxelles

Re: Matrix Multiplication

Post by karthiks »

yrenard wrote:The Simple DSP does not multiply matrices.

karthiks, there is no general purpose matrix multiplication box as this is not really meaningful for the scenario author, this should probably be done at a lower level, by a developer.

Still, you can multiply a vector of samples by a matrix using the Spatial Filter box but this may not be what you want.

What is the purpose of that multiplication you want to achieve ?

Hope this helps,
Yann
Hey Yann,

Thank you for the reply.

I am trying to do an ICA calculation which involves multiplying two matrices (one of them being a static pre-calculated matrix and the other a live streaming signal matrix).
Regards,

Karthik

yrenard
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Re: Matrix Multiplication

Post by yrenard »

Dear Karthik,

if you do ICA, you then probably want to apply a spatial filter :) Just have a look at its documentation ; you could also be interested in one of the xDAWN p300 speller or the CSP motor imagery scenarios which actually use similar filters... and of course, don't forget to share your ICA training box ;)

Hope this helps,
Yann

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