The user must insure that
their computing platform has sufficient physical memory. Not
surprisingly, the amount of memory required depends directly on the
size of the problem you would like to solve. To determine the
size of the problem four characteristics of the input data must be
calculated; the number of cells, persons, firms, and covariates.
The number of persons and firms as well as the number of
covariates or right hand side variables should be relatively
easy
to ascertain (although make sure to give the last value some thought
and use an upper bound, since memory usage increases almost linearly
with the number of covariates). The cells total refers to the
sum
over all persons of the number of unique firms each person has
worked for. A sample SAS program to calculate this value is
available here.
Once you have obtained the number of cells, persons, firms, and
covariates, plug them into the calculator and press the calculate
button. In the bottom row, you will receive the minimum
memory
(in megabytes) required to run CG2.
If the value returned by the calculator is less than about .7*(Physical
Memory) and you can meet all of the other requirements, then
CONGRATULATIONS you are ready to begin installing CG2 (Keep in mind
that the .7 figure is only an estimate based on our experience and will
likely vary across platforms depending on how much memory is used by
the operating system, other users, daemons, etc. Feel free to
replace my estimate with a number appropriate for your
situation).
