logic behind sumproduct

I typed all of this out already, then Excelforum decided it wanted to lock up and delete everything, to teach me the virtue of patience.


Anyways, here we go again.

It is an array formula. It gives you the Summed product of two arrays, so So sumproduct(a1:a3,b1:b3) would do this:
SUM(a1*b1,a2*b2,a3*b3)
Or,


In your example formula, it would do this

{c2=1, c3=1, c4=1,......} all the way to c22. Then result would be like the following,
{TRUE,TRUE,FALSE,TRUE,TRUE...}
Then you put a double negative in, --, which converts it to a 1 or a 0 depending on TRUE or FALSE
{1,1,0,1,1...}

Then the other part,
{e2>=d2, e3>=d3, e4>=d4...e22>=d22}
it will also return true's and falses, lets say
{1,0,1,0,1...}

Now, we multiple them, which is the PRODUCT part

{1*1,1*0,0*1,1*0,1*1...}
which is
{1,0,0,0,1...}

Then we SUM those 0's and 1's to get the end result, which in this case is
1+0+0+0+1 = 2

Hope this helps!~



Edit; technically those should be semicolons between the values and not commas, oh well.

Semicolon notes new row, comma is new column

so {0,1;2,3;4,5} would represent a table of

0	1
2	3
4	5