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I am using AceGen to compile a subroutine for MATLAB. The subroutine involves several steps of linear algebra that yields a number of symmetric matrices. However, when using AceGen there seems to be some sort of optimization process that, when dealing with a symmetric matrix, only returns the upper triangularization of the matrix. How can I make sure that AceGen always uses the full symmetric matrices?

I have created a very simple example to illustrate my point. Consider the function "TestFunction" that takes in an arbitrary ${5\times 5}$ matrix (called input) and returns a few symmetric matrices (called output1, output2, and output3) where

$$ output1 = \frac{1}{2} \left( input + input^{T} \right) \,, $$ $$ output2 = input^{T}\, input \,,\text{ and} $$ $$ output3 = output2^{-1} \,. $$

The AceGen source code for "TestFunction" can be found here and is shown below

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The compiled MATLAB code is available here.

The compiled MATLAB function is tested using the script "TestScript" which is available here and shown below.

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The outputs of "TestScript" are shown below.

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The outputs are close to correct. However, instead of just the upper triangular matrices, I want the outputs to be the full matrices, as shown by the MATLAB outputs.

I have tried changing the optimization mode to "Mode"->"Plain" I have tried using

$$ \text{SMSFreeze}\left[output1,\, \frac{1}{2} \left( input + \text{Transpose}\left[ input \right] \right) ,\, "Symmetric"->\text{True} \right] \,, $$

$$ \text{SMSFreeze}\left[ output1,\,\frac{1}{2} \left( input + \text{Transpose}\left[ input \right] \right) ,\, "KeepStructure"->\text{True} \right] \,,\text{ and} $$

$$ output1=\text{Table}\left[\frac{1}{2}\left( input [i,j] + input [j,i] \right),\{i,1,ndim\},\{j,1,ndim\} \right] $$

but nothing has worked.

Any help would be appreciated!

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  • $\begingroup$ Can you paste your code as a code instead of an image? $\endgroup$
    – Karol Frydrych
    Commented Jul 2, 2021 at 6:03
  • $\begingroup$ There are links to the code labelled as 'here' in the question. These are in red and underlined. I tried pasting the code but I could not get the formatting right. So I just uploaded the code files to a shared folder accessible via the 'here' links $\endgroup$
    – DvanHuyssteen
    Commented Jul 2, 2021 at 6:06
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    $\begingroup$ Indeed, using your generated code only the upper triangular matrix is shown. I have noticed you are using version 7.006 of AceGen. I would suggest to use newer version (I'm using 7.101 but there is 7.208 already available). $\endgroup$
    – Karol Frydrych
    Commented Jul 2, 2021 at 8:03
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    $\begingroup$ I have 7.208 already and have no Matlab at the moment so i cannot reproduce the problem, at least with Mathlink code returns full matrix. Can you try exporting within double SMSDo loop each element individually? Maybe that will work. $\endgroup$
    – BHudobivnik
    Commented Jul 2, 2021 at 10:43
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    $\begingroup$ @BHudobivnik For some reason exporting in a double SMSDo loop didn't work properly, probably an implementation error. However changing SMSExport[OutputMatrix1, output1\$\$]; to SMSExport[OutputMatrix1, Table[output1\$\$[i, j], {i, 1, ndim}, {j, 1, ndim}]]; has worked and now the full matrix is being exported as I want :D $\endgroup$
    – DvanHuyssteen
    Commented Jul 15, 2021 at 7:56

2 Answers 2

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Export the components of the output matrices individually by changing the export section from

SMSExport[OutputMatrix1,output1$$];
SMSExport[OutputMatrix2,output2$$];
SMSExport[OutputMatrix3,output3$$];

to

SMSExport[OutputMatrix1, Table[output1$$[i, j], {i, 1, ndim}, {j, 1, ndim}]];
SMSExport[OutputMatrix2, Table[output2$$[i, j], {i, 1, ndim}, {j, 1, ndim}]];
SMSExport[OutputMatrix3, Table[output3$$[i, j], {i, 1, ndim}, {j, 1, ndim}]];
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There was a bug in Matlab export that has been recently removed. Yust, update your AceGen.

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