Iterative Formula Calculations with Randomly Generated Variable Values

**Muradi101** · 04-05-2017, 05:33 AM

Good day,

First off, I would like to state that I am not a proficient user of Excel. I've done some research online in an attempt to find a solution to my problem, but to no avail. I would appreciate any kind of assistance and I'd like to thank everyone in advance for their time and efforts.

My problem is as follows:

I have 3 cells, lets name them A1, B1 and C1
C1 contains a Fluid Mechanics formula that requires a Value be inputted in B1 to generate a value.
A1 just contains a number value, say 150.

Is there a way where excel would input random values in B1 and recalculate the formula in column C1 iteratively until the results in C1 equal the number value in A1?

I do apologize if i haven't explained this clearly enough. Id be happy to explain further if the need arises.

Thank you,
Muradi

**sweep** · 04-05-2017, 06:49 AM

Hi,

I think that the goal seek fuctionality in excel will do as you require, although to target a value in a specific cell would probably require some vba.

https://www.timeatlas.com/excel-goal-seek/

**MrShorty** · 04-05-2017, 10:26 AM

Is there a way where excel would input random values in B1 and recalculate the formula in column C1 iteratively until the results in C1 equal the number value in A1?

Do you really want your algorithm to try "random" numbers until it accidentally stumbles upon the correct root? It seems to me that a fluid mechanics problem would prefer a Newton-Raphson or bisection or similar root finding algorithm where the test values are not exactly randomly chosen but are chosen by much more efficient algorithms.

As sweep suggests, the built in goal seek and solver utilities are probably the easiest ways to implement these kind of root finding algorithms. If you are interested, I illustrate (using polynomials) how to program these into the spreadsheet without Goal seek/Solver here: https://www.excelforum.com/tips-and-...ind-roots.html