LSM6DSOX MLC storage size

NGern · ‎2019-09-20

I'm wondering what the hard limit is for the MLC configuration in the LSM6DSOX. I'm using Unico 9.0.0.0 to configure four IIR2 filters and I loaded 4 decision trees (basically a small random forest). The Unico software created the .ucf file successfully. But when I wrote the configuration into the LSM6DSOX, it wouldn't give me any valid values in the register that held the decision tree outputs. The valid outputs were 1, 2, and 3, and the registers would only report 0.

Is there a documented size limit on this MLC size? Even if there is a software bug in this version of Unico, it would be nice to be able to double-check to see that the .ucf file isn't configured to write past the end of the memory map.

Eleon BORLINI · ‎2019-09-24

Hi @NGern , the HW limitations are the below depicted ones, so you shouldn't have exceeded them with your MLC configuration (N. of decision tree <8, few features, etc).

Is the decision trees you generated from your tool in the below format? Please note that the decision tree has been generated from a different tool, the format must be converted to the Weka J48 format (or to the RapidMiner format) in order to allow the Machine Learning Core tool in Unico to read the decision tree correctly (cfr AN5259, p.23) .

Moreover, did you try to run 1 decision tree per time in Unico?

Regards

NGern · ‎2019-09-24

Thanks for the reply @Eleon BORLINI . Yes I did use Weka to generate the decision trees. I used the RandomForest model which generated 4 decision trees that were in the same format as the J48. An example of one of the trees from the RandomForest output is attached.

I was also wondering about the filtering capability, or the features. I'm wondering about this because I have also tried a single J48 decision tree (generated from Weka) with the 4 IIR2 filters, and the LSM6DSOX still only generated the invalid decision '0' where the valid outputs of the decision tree were '1', '2', and '3.' Is there a limit on the number of filters that can be utilized by the MLC, or a limit to the number of features the part can process? Can the part, for example, handle 10 different IIR2 filters?

Eleon BORLINI · ‎2019-09-26

Hi @NGern , thank you for the shared data. Your tree seems to have been defined by a lot of feature (up to 32), and I think that most of them are not useful in your decision tree. Which activity do you want to detect / classify? No problem configuring 4 IIR2, but being these filter highly configurable, you maybe could use only one or two of them. Can you share some more detail about your logs and the Unico configurations of your MLC application?

Strictly speaking, referring to the filter/feature limitation, it is related to the device memory and not to Unico. Regards

NGern · ‎2019-09-26

Hey Eleon,

I've found empirically that the LSM6DSOX will report the invalid output pretty consistently with 4 IIR2 filters in my application. I'm having more luck configuring just 3 IIR2 filters. My original question was trying to find out if ST knows the limitations of their hardware in terms of the number of filters that can be configured.

Our application is that we're differentiating between different states of vibration in a vehicle.

For the number of parameters, it could be that 32 is a lot but the Unico tool allows me to use that many. It seems like the LSM6DSOX can't process that many though. I've empirically found that I can have about 25 to 30 features in the decision tree before the LSM6DSOX breaks.

Just from my user perspective, Unico should be enforcing the memory / hardware constraints of the LSM6DSOX (i.e. I shouldn't be able to configure 4 IIR2 filters in the software if it breaks the LSM6DSOX). Thank you for your help though.

Eleon BORLINI · ‎2019-09-27

Thank you indeed @NGern for the detailed explanation of your test case. Please note that the DSOX MLC is a "developing" area yet. We are testing basic- and medium-complexity configurations, but still need to work on it. So thank you again for your contribution. I checked with our MLC experts and Unico developers and to better help you they need the detailed flow of your application (from the datalog, the feature etc...). You can share them via private message, if you want. Regards

Eleon BORLINI · ‎2019-10-09

Hi @NGern , a new Unico GUI version is available here (9.3.0). Please check if this new version, that contains some modifications in the MLC part, can solve or mitigate the issues you are facing. Regards

NGern · ‎2019-10-09

Thanks for the head's up - I'll check it out!