Order of operations when doing math to set a field value

[Jeremy Steuhl]

I have a project I use to track my vehicle maintenance and fuel logs.  I'm trying to automate my fuel milage "MPG".

I have 3 custom numeric fields:

issue.customfield_10216 = Current Mileage ie 31,796 miles

issue.customfield_10215 = Previous Mileage ie 31,271 miles

issue.customfield_10213 = Gallons 33.5 gallons of fuel 

In something like excel, I'd have a formula:  (issue.customfield_10216-issue.customfield_10215)/issue.customfield_10213

which would result in 15.7 MPG.

Looking at documentation, I'm able to get the first part to work by subtracting issue.customfield_10215 from issue.customfield_10216 resulting in 525, but when I try to divide that by issue.customfield_10213 it just sets the field to 525, instead of doing the division, almost like it's ignoring the rest of my formula.

Here's my formula:  {{issue.customfield_10216.minus(issue.customfield_10215).divide(issue.customfield_10213)}}

I tried wrapping the first part in () like this, but that just ended up in error:

{{(issue.customfield_10216.minus(issue.customfield_10215)).divide(issue.customfield_10213)}}

Any suggestions on how to write this properly?

[Trudy Claspill · Accepted solution]

Hello @Jeremy Steuhl 

First I recommend that you use the Log action in your rule to print to the rule's Audit Log the value of each of those custom fields to ensure the values used in the calculation are what you think they are.

I tried your math using just Log actions to see the results. First I printed the three values. Then I printed just the .minus operation. Then I printed the full math function. Oddly the results ended up in the wrong order in the log file, but the final full match function result was correct.

[Jeremy Steuhl]

Thanks.  Can post a screen shot(s) of the rule as you set it up?  You said you used my formula but when I use it, I don't get the right answer.  Also, I'm not familiar with using the log action in a rule.  I'm not sure based on the documentation how to enable that.  I'm hoping your screenshot(s) will answer that for me. :)

[Trudy Claspill]

I was using whatever number fields were available so my fields compared to your fields are

Yours	Mine
issue.customfield_10216	Story Points
issue.customfield_10215	Custom Story Points Number
issue.customfield_10213	SK Only Number Field

[Jeremy Steuhl]

Thank you so much.  Adding values to the audit log helped me solve the issue.  The problem I was having in my formula was that I transposed a few numbers, so the formula was working, but it wasn't using the right field. 

I was using issue.customfield_10213

when the field was actually issue.customfield_10123.  

Putting everything in the audit log showed me that and now it works.