Math Forum Discussions

Goyder Dr HGD

Posts: 59
Registered: 1/29/05

Monitoring status of dynamic calculation
Posted: Sep 25, 2009 7:51 AM

Plain Text

I have a notebook with many (possibly 100) dynamic variables. I do a
calculation using these variables and get a result. If I change one of
my dynamic variables then the results of the calculation are no longer
correct and I need to do the calculation again. What I need is a
method for identifying the status of the calculation. Is it current
and correct or has one of the variables changed and it is now out-of-
date?

I give a toy example below where pressing a button corresponds to
doing the calculation and setting a status flag to current. If I
change one of the dynamic variables then I want the status to change
to out-of-date. I give an input field with a dynamic with a second
argument which enables me to change the status. This works but my
problem is that I have many ways of changing the dynamic variables and
I cannot associate each with a two argument dynamic. I thus need a
general way of checking to see if a variable has changed and if so
updating the status. Is this possible?

Thanks
Hugh Goyder

(divide the cell where line spaces occur)

ClearAll[x];
n=10;
a=Table[{i,x[i]},{i,n}];
Status="Out-of-date";

TableForm[{#[[1]],Dynamic[#[[2]]]}&/@a]

Do[x[i]=RandomReal[],{i,n}];

Row[{Button["Mean",b=Mean[a[[All,2]]];Status="Current"],"Mean =
",Dynamic[b]," Status = ",Dynamic[Status]}]

InputField[Dynamic[x[1],(x[1]=#;Status="Out-of-date")&]]

x[2]=2