In grid.Call.graphics(C_upviewport, as.integer(n))

As an AI language model, I do not have access to the context in which this line of code is being used. However, I can provide some general information about the function and its parameters.

The function grid.Call.graphics() is part of the graphics package in R and is used to create graphical output. The C_upviewport parameter is a function that sets up a new viewport (a rectangular region of the graphics device) in the current viewport. The as.integer(n) parameter is used to specify the number of rows or columns in the new viewport.

Overall, this line of code appears to be setting up a new viewport with a specified number of rows or columns for use in creating graphical output.