what does mean the 'nstp' and 'nout'?

[free]

Code: Select all

 dUdt=u(Iend,j,k,nstp)-u(Iend  ,j,k,nout)
dUdx=u(Iend,j,k,nout)-u(Iend-1,j,k,nout)

Hi,
I am a newer, what does mean the 'nstp' and 'nout'?
Thank you!

[kate]

The fourth dimension of u is for different times. nstp and nout are small integers pointing to "step" and "out" time levels.