Hello,

I'm having some problems figuring out how to write a

code that would make an iteration stop after, for

example, there is no more difference between result

from one previous step of iteration and result from

current (last) step of iteration. I only know how

to manually write the number of iterations but I

would like the computer to determine itself how

many are needed and then stop. Here is the example from code:

Code:

for (iter=0; iter<=40; iter++)
{
for (i=1; i<=2; i++)
for (j=1; j<=2; j++)
g[i][j]=0.25*(p[i][j+1]+p[i][j-1]+p[i+1][j]+p[i-1][j]);
for (i=1; i<=2; i++)
for (j=1; j<=2; j++)
p[i][j]=g[i][j];
}

Basically, g[i][j] is small example array of 4 x 4

elements and the formula written above takes values

from surroundig elements and updates the g[i][j]

value 40 times. With every iteration there is less

and less difference between last value and the new value.

How would this code above have to be modified so

that this is done automatically, ..I mean - that

you don't have to do "guessing" the number of

iterations and that iterations stop after there

is some minimal difference between last and new value?

thanks,

Tom