math ultimate Node returns SUM instead of selected method for SUBSTRACT values

[VanillaFord]

When selecting the Substract method, the math ultimate node reports using the SUM method instead. In addition, the returned payload is the SUM of all absolute values of the msg.payloads going into the node and not the substract value of all msg.payloads going in.

See screenshot:

in that example, the values with three different topics are send into the node, which is configured to use substract method. From the debug Nodes:

• Value 1: -1244.50
• Value 2: +1133.46
• Value 3: -2417.00 Results:
• from Node (reporting using SUM): 4794.96 = abs(-1244.50) + abs(1133.46) + abs(-2417.00) -> wrong
• from math calculator: (-1244.50) - (+1133.46) - (-2417.00) = +39.04

[Supergiovane]

Hi I’ll take a look tomorrow morning…

[Supergiovane]

Hi

from math calculator: (-1244.50) - (+1133.46) - (-2417.00) = +39.04

You're assuming (right assumption), that the first topic the node receives is -1244.50. Currently, the "subtract" function deals with the numbers like this instead: - (-1244.50) - (+1133.46) - (-2417.00), so the -1244.50 becomes +1244.50.

I could assume that the first topic received, is the number to start subtracting for. Your're right. I'll publish a fixed version asap.

[Supergiovane]

Hi Should be fixed. V. 1.1.4 is out.

[VanillaFord]

Hi @Supergiovane

thanks for your prompt response and support. Unfortunately this bug is not fixed for me:

The "correct" value from a calculator is +18, here.

I could assume that the first topic received, is the number to start subtracting for.

No, I was not assuming that. The order of appearance - as well as the number of measures/topics - is not assumed for....as NR is event based, any topic could arrive at any time. However, in my example/flow the number is fixed (3). The node should (re-)calc with every incoming msg using any number of available measures/topic at that time. If helpfull, maybe make the number of measures (optionally) fixed so if not all expected/configured topics did arrive at least once, the node would not output a wrong value?

[VanillaFord]

...here is another example: ...the correct/expected value would be: 2062.4 = (-17.1) - (0) - (-2079.5)

[Supergiovane]

Hi yes, i could do that, but the problem still persist. Given all 3 topics, what number should the calculation start with? With "sum" and "multiply", there's no issues, but with "divide", what number should i take first?

(-1244.50) - (+1133.46) - (-2417.00) is not equals to, for example, (+1133.46) - (-2417.00) - (-1244.50)

[VanillaFord]

Ugh, I see...yes, you are right, the calculation is order sensitive...I totally did miss that. :-( I apologize for not taking this into account. In my Case obove it should be: ((GRID_Power - House_Power) - CPs_Power)

But then, substraction method for this node can only be valid, if ordering of the topics is given, as well as numbering (like having three inputs for 3 measurements in the node and give order 1,2,3) or order of topic names.

That makes it very complex to implement, is it not?

Also: it apears, that in V1.1.5, the node does not change payload (and average) after the first calc, even if fed with new values from each topic (in my flow the input msgs have a cadence of approx 10ms). It does output the same response with every input msg...and does a re-calc after receiving a msg.reset, though. This is true, even when selecting SUM or multiply operation instead of substract Should I create a separate issue for that? It definitely worked with previous version

[Supergiovane]

Hi i'll take a look at the average. About the "subtract", i can put another property in the config window. Here you can write the topic name that should be taken into account, as the first number. You can set it to "GRID_Power", for example. Could this do the trick?

[Supergiovane]

In the meantime, i've fixed the "average".

[Supergiovane]

Please try the 1.1.6. You must now set a msg.topic to start subtracting from.

[VanillaFord]

Could this do the trick?

Yes I think it could, thank you.

In the meantime, i've fixed the "average".

Perfect, please keep in mind, that the payload is also affected.

Thank you very much in advance for your support!

[VanillaFord]

Please try the 1.1.6. You must now set a msg.topic to start subtracting from.

...this version doesn't show up in the pallette manage, yet

[Supergiovane]

Should show up in some minutes... npmjs takes a little log to update.

[Supergiovane]

Could this do the trick?

Yes I think it could, thank you.

Perfect, please keep in mind, that the payload is also affected.

The payload is not sent until the main topic hasn't been received.

[VanillaFord]

Should show up in some minutes... npmjs takes a little log to update.

Yep, now it is showing (v1.1.7) ...and a first test confirms, that it is working now. Thank you very much for your fast response and support!!

[Supergiovane]

You’re wellcome!!