10.4 Memory requirements for simulation of a project
The memory requirements obviously depend on the number of FDTD cells in the particular project. That is why it is recommended to verify the expected number of cells before invoking starting the simulation. The number of cells is shown in the Mesh/Splanes Info dialogue. This will help avoiding the software crash on memory requirements when the number of FDTD cells exceeds that allowed by the memory capacity of used computer system. If the user knows that he is running a project at the limits of the memory capacity it is recommended to take advantage from the “Step-by-step” simulation execution functionality. Before ending the pre-processing stage the QW-Simulator will clearly signal the possible memory capacity problem.
On top of the operational system and user applied programs residing in the computer memory QW-Simulator alone (working with a reasonable number of display windows) occupies up to 30MB of RAM. This number should be increased by:
approximately 100 Bytes per one FDTD cell (minimum 72 Bytes if the project is filled with lossless dielectric media),
about 160 Bytes per a frequency point and per port in the S-parameter calculation,
about 50 Bytes per one FDTD cell of the NTF surface and per one frequency at which the radiation patterns are calculated.
QW-Editor loaded with a project of a typical size occupies less than 50MB of RAM. The memory requirements rise during the Export operation. At this stage, they depend on the number of FDTD cells and become close to those of QW-Simulator. However, since at this stage QW-Simulator is not supposed to be working, we can count that the general memory requirements are those of QW-Simulator plus about 50 MB if we keep QW-Editor open during QW-Simulator operation.