Problem Displaying Specific Data From a Simple Model

Hi, this may well be something basic that I'm missing, but I seem to be hitting my head against a brick wall. Any help would be gratefully appreciated!

I'm trying to run a basic model, the time step for the model is small (0.01), so I only want to display the data at a few key time points. The code seems to do this okay for small numbers (the initial time point is 1 and if I ask it to report m at t = 1.02 and t = 1.03 it will display the correct result in the requested cells) but not for anything much higher (I need it to report m at t = 1, 2, 3 ect up to 10, but if I ask it to report m at t = 2 and t = 3 nothing appears on the spreadsheet).

Private Sub CommandButton1_Click()
k = Cells(3, 2)
y = Cells(4, 2)
dt = Cells(6, 2)

im = Cells(9, 2) 'im is initial mass
it = Cells(10, 2) 'it is initial time

m = im
t = it

Do While t < 10

dmdt = k * Exp(-y * t) * m
dm = dmdt * dt
m = m + dm
t = t + dt

    If t = 2 Then
    mii = m
    End If

Cells(13, 2) = mii

If t = 3 Then
    miii = m
    End If

Cells(14, 2) = miii
    
Loop
End Sub

If you need any more information, please let me know. Thanks in advance, Jo

Hi abousetta, it's 3.30am for me so I'm probably not much better!

I'm pretty new to this, so I might be completely wrong, but I set it to less than 10 as I only need to see the results up until the time (t) equals 10? Either way, that part of the model seems to run okay, it's getting the results I need onto the spread sheet that's the problem.

What I would like to happen is that when t hits 2, for the mass (m), at that point, to be reported on the spread sheet, then when t hits 3, the result for m at that point to be reported in the cell below.

Like I said above, it works if I ask it to report m when t = 1.02 (or 1.03 etc up to 1.1), but when I increase t above 1.1 it runs, but doesn't put anything in the cell.

Try changing

If t = 2 Then
    mii = m
    End If

for

If t = 1.02 Then
    mii = m
    End If

and you might see what I mean better.

I need to graph the data with results from other models. Different models have to be run at different time steps, so to save confusion I just want to see the results for m at the time steps 1, 2, 3 etc., not all the smaller time steps between.