Conditional sum, wizard or otherwise

[James Silverton]

Hello, All!

There was a question recently on numerical integration. I can
see how to do it using Simpson's rule and the most appropriate
function would be SUMIF but, if there are two columns, x and y,
I cannot think how to sum the y-values when x is odd using ISODD
(or equally ISEVEN). Can someone point me in the right
direction? I could write an expression using IMOD but that seems
clumsy.

Thanks in Advance!

James Silverton
Potomac, Maryland, USA

 

[James Silverton]

James wrote to All on Fri, 20 Jan 2006 18:36:42 -0500:

JS> There was a question recently on numerical integration. I
JS> can see how to do it using Simpson's rule and the most
JS> appropriate function would be SUMIF but, if there are two
JS> columns, x and y, I cannot think how to sum the y-values
JS> when x is odd using ISODD (or equally ISEVEN). Can someone
JS> point me in the right direction? I could write an
JS> expression using IMOD but that seems clumsy.

I should mention that I have seen various approaches involving
helper columns and I successfully did that with results that
were pretty good using a function that I could integrate exactly
to allow checking.

James Silverton.