brackets { } in excel formulas

[Guest]

I am working with an excel workbook that contains a large number of formulas.
Some of the formulas contain an additional set of curly brackets { } around
the entire equation. If I double click on the formula to see what cells the
formula is drawing from and then hit enter when I am done, the cell where the
formula is contained shows an error. What function do the additional
brackets serve?

Example of formula:
={POWER(10,(SUM(IF(CalPgms=0,0,logPM)) - SUM(IF(CalPgms=0,0,logEAF))) /
SUM(IF(CalPgms=0,0,1)))}

 

[Guest]

The curly brackets denote an array formula - one that typically works on an
array of values rather than on a single value. You get an error because the
formula must be committed with the Ctrl+Shift+Enter key combination.

 

[Guest]

One other thing - don't try to enter the curly brackets yourself. Excel will
do this when you commit w/Cntrl+Shift+Enter