Trying to improve efficiency of array formula

  • Thread starter Thread starter Anthony
  • Start date Start date
A

Anthony

I have a SUM array formula that has multiple nested IF statements,
making it very inefficient. My formula spans over 500 rows, but here
is a simple version of it:

{=SUM(IF(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0,
IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17,0))}

As you can see, the first half of the formula checks where the array
is greater than zero, and if they are, it sums those in the second
part of the formula.

You will notice that the same IF statement is repeated in there twice,
which to me is inefficient, but is the only way I could get the
correct answer.

The example data I have is as follows:

Row Col A
1 120
2 120
3 120
4 120
5 120
6
7 100
8 100
9 100
10 100
11 100
12
13 50
14 50
15 50
16 50
17 50

The answer should be 350 in this instance using the formula I
mentioned above.

If I tried to put in a MAX statement within the array, therefore
removing the test to find where it was greater than zero, so it was
like this:
{=SUM(MAX(IF(B2:B6>B8:B12,B2:B6,B8:B12)-B14:B18,0))}

However, it seems like it only calculates the first row of data in
each range, and it gave me the wrong answer of 70.

Does anyone know a away that I can reduce the size of the formula or
make it more efficient by not needing to repeat an IF statement in
there?
 
Hi,

You might consider an SUMPRODUCT function such as:

=SUMPRODUCT(--(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0),--(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17))

If this helps, please click the Yes button

Cheers,
Shane Devenshire
 
Hi,

You might consider an SUMPRODUCT function such as:

=SUMPRODUCT(--(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0),--(A1:A5>A7:A11,A1:­A5,A7:A11)-A13:A17))

If this helps, please click the Yes button

Cheers,
Shane Devenshire
Click to expand...

Hi Shane

I tried your suggestion, but it just gives a #VALUE error (even if i
press Ctrl Shift Enter to make it an array formula)

Anthony
 
Hi,

Didn't test, try this instead:

=SUMPRODUCT(--(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0),--IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17)

Array entered. I don't know if this is the result you want but with dummy
data I get a result.

Cheers,
Shane Devenshire
 
Hi,

Didn't test, try this instead:

=SUMPRODUCT(--(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0),--IF(A1:A5>A7:A11,A­1:A5,A7:A11)-A13:A17)

Array entered.  I don't know if this is the result you want but with dummy
data I get a result.

Cheers,
Shane Devenshire








- Show quoted text -
Click to expand...

Shane

That works, but i think i have found an even more efficient method:

=MAX( MAX( sum(A1:A5), sum(A7:A11) ) - sum(A13:A17), 0)

It seems to work OK from my initial tests.

Anthony
 
Hi,

I don't know how much this will improve the efficiency but if the range
unchanging you can define a name, say T which is equal to
=IF($A$1:$A$5>$A$7:$A$11,$A$1:$A$5,$A$7:$A$11)-$A$13:$A$17
then you spreadsheet formula becomes
=SUMPRODUCT(--(T>0),T)
which does not need to be arry entered. If you want the ranges to be
relative then naming the range is a little tricker, select the cell where you
are going to enter the formula and then choose Insert, Name, Define, enter T
as the name and in the Refers to box enter
=IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17
The formula in the spreadsheet is the same as above.

I also notice that even if you don't consider any of these ideas you can
simplify the original suggestion to

=SUMPRODUCT(--(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0),IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17)

All that's changed is the -- in the second part of the formula. It still
needs to be entered as an array.

Cheers,
Shane Devenshire
 
That works, but i think i have found an even more
efficient method:
=MAX( MAX( sum(A1:A5), sum(A7:A11) ) - sum(A13:A17), 0)
It seems to work OK from my initial tests.
Click to expand...

It certainly is not the same as your original array formula in
general, unless there is something about your data that you have not
explained. Consider the following random data:

Row Data
1 114
2 144
3 126
4 142
5 182
6
7 172
8 100
9 120
10 100
11 100
12
13 50
14 50
15 50
16 50
17 50
 
My formula spans over 500 rows, but here is a
simple version of it:
{=SUM(IF(IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17>0,
IF(A1:A5>A7:A11,A1:A5,A7:A11)-A13:A17,0))}
Click to expand...

My interpretation of what you want is:

=MAX(A1-A13,A7-A13,0) + MAX(A2-A14,A8-A14,0) +
MAX(A3-A15,A9-A15,0) + MAX(A4-A16,A10-A16,0) +
MAX(A5-A17,A11-A17,0)

I'm not suggesting that as a solution, of course. It's just a
conceptual module. More generally:

=sumproduct(max(A1:A5-A13:A17, A7:A11-A13:A17, 0))

That does not work as intended, of course. Again, just a conceptual
model. I had hoped to make SUBTOTAL work, but I have not succeeded.
 
My interpretation of what you want is:

=MAX(A1-A13,A7-A13,0) + MAX(A2-A14,A8-A14,0) +
 MAX(A3-A15,A9-A15,0) + MAX(A4-A16,A10-A16,0) +
 MAX(A5-A17,A11-A17,0)

I'm not suggesting that as a solution, of course.  It's just a
conceptual module.  More generally:
Click to expand...

Yes, your conceptual model is correct, however i need to build an
array formula that would give the same result.

Anthony
 
Back
Top