# Is there any limit for CF calculations?

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Dear all,

I created the following Peak, Real CF: (EQ(Label,"U0002"))*(ABS((U0002.%.(Area)-S0101.6.(Area))/((U0002.%.(Area)+S0101.6.(Area))/2)*100))+(EQ(Label,"U0003"))*(ABS((U0003.%.(Area)-U0002.%.(Area))/((U0002.%.(Area)+U0003.%.(Area))/2)*100))

The CF works fine. But if I add a further function like +(EQ(Label,"U0004"))*(ABS((U0004.%.(Area)-U0003.%.(Area))/((U0004.%.(Area)+U0003.%.(Area))/2)*100)) the CF didn`t work any longer (no values are shown in the CF).

Is there any limit for such calculations? Or did I have a mistake in the formular?

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I believe there is an error in your second portion of the formula.

You have:
+(EQ(Label,"U0004"))*(ABS((U0004.%.(Area)-U0003.%.(Area))/((U0004.%.(Area)+U0003.%.(Area))/2)*100))

I believe it needs to be:
+(EQ(Label,"U0004"))*(ABS((U0004.%.(Area)-U0003.%.(Area))/((U0004.%.(Area)+U0003.%.(Area))/2)*100)))

By my eye, you have left the first parentheses open. This may be why the formula works when there is only one condition. Once you add the second, the first condition isn't closed out. In other words, it also looks like you done the same thing in the portion of the equation that is working and it stops working when the second portion is added because the first EQ logic is never closed.

To aaswert your question, yes you can either try to do too much in one custom field or have too many custom fields in a project that calculations will no longer proceed. There is a limited memory space allowed for custom fields and their calculations. Once this memory s exceeded the custom fields simply stop.

The above turned out to be a fairly big problem when I coded the USP dissolution monograph (all release types) for a client. I ended up having to separate out the release types into different projects, which was not inline with the all dissolution in one project strategy. If you want that approach to work, you either need to offload via the toolkit or into LIMS (also via the toolkit).

I would guess after having learned the above, that the Waters dissolution options utilizes the toolkit and an external calculation source. However, I've never actually used the option so I really don't know.