16.21.1                Memory requirements

The memory requirements obviously depend on the number of FDTD cells in the particular project. That is why we suggest verifying the expected number of cells before invoking Export&Run command from QW-Editor. The number of cells is shown in the Mesh Info dialogue in QW-Editor or in Mesh Inspect dialogue in Test Mesh window in QW-Simulator. This will help us to avoid the situation when memory requirements when the number of FDTD cells exceeds that allowed by the memory capacity of used computer system. If you know that you are running a project at the limits of the memory capacity please do not use Export&Run command but rather Export (in the Editor) and Create (in the Simulator – for the main project and not the initial Create for the templates). In such a case the QW-Simulator will clearly signal the possible memory capacity problems.

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.