I have 30 numbers, some are positive and some are
negative. I want to calculate something called "becker's
IRR" on the 30 numbers. This is what exactly what I mean
by "becker's IRR": if a number is negative, I look at the
numbers immediately before it, until I find a positive
number.

Example: I have numbers: 10, 20, -9, -25, 44, 99. Now -9
and -25 are negative, so I discount them back to the
positive number before them, which is 20, using a constant
IRR rate of 0.05. And I get: 20+ (-9)/1.05 + (-2)/1.05^2 =
9.6. Now I form a new set of numbers: 10, 9.6, 0, 0, 44,
99. Since all the numbers in the sequence are positive.
I'm done. Essentially, I want to get a sequence of non-
negative numbers.

Please help.

Wei