Vector Calculations

**dmillier** · 05-03-2010, 04:31 PM

Look in the attached file for the calculations I'm trying to perform. I am wanting to multiply the values in B by C, not changing the A row, but starting at the beginning of C and then SUM the values for each of the resulting multiplication (for example summing the numbers for each month).

I've tried using a SUMPRODUCT, but wasn't sure how to set it up to work. Thanks for your help in advance.

**DonkeyOte** · 05-03-2010, 06:04 PM

Perhaps if I've understood

O5:
=SUMPRODUCT($B$5:$B5,SUBTOTAL(9,OFFSET($C$5,(ROWS($C$5:$C5)-(ROW($C$5:$C5)-ROW($C$5))-1),0)))
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Note: above is Volatile given use of OFFSET.

**dmillier** · 05-04-2010, 08:47 AM

DonkeyOte,
Thanks so much for your help. I really appreciate your willingness to help me out. Good luck with all of your future excel endeavors.

**dmillier** · 05-06-2010, 04:28 PM

I have an expansion on the previous post. It's similar to the previous task, but slightly more involved. I'm not completely comfortable with the OFFSET function or the PRODUCTSUM function and I have been trying to figure it out with no luck. It is in the attached file. I tried to make it as straight forward as possible. Let me know if you have any questions. Thanks.

**DonkeyOte** · 05-07-2010, 05:44 AM

Given you've asked this question in a separate thread (which is preferable)

http://www.excelforum.com/excel-gene...culations.html

I would suggest you denote this particular thread as Solved.

**DonkeyOte** · 05-07-2010, 06:29 AM

Though FWIW in case anyone should find this:

G10:
=SUM(($D$10:$D10*LOOKUP($B10-$B$10:$B10,{0,5,8},$A$1:$A$3))*IF($B10-$B$10:$B10>=8,INDEX($C$10:$C10,1+ROW($C10)-ROW($C$10))*300,1))
confirmed with CTRL + SHIFT + ENTER
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