Calculation Options Tab

This tab displays the current settings in the Property Editor for calculation options. To change this, click Analysis > Calculation Options and change the settings in the Property Editor.

The Calculation Options tab displays the following information:

Label	Displays the currently selected calculation options.
Duration	Displays the duration of the model simulation.
Calculation Time Step	Displays the calculation time step used in calculations of your model.
Output Increment	The Output Increment you want to use to display the output hydrographs of a network analysis.
Hydrologic Routing Time Step	Lets you specify the computational time step in hydrology runoff calculations.
Y Iteration Tolerance	Implicit numerical scheme Newton iteration convergence criteria for depth/elevation. It is strongly recommended that you use the default value.
LPI Coefficient	Displays the LPI coefficient used in calculations of your model.
NR Weighting Coefficient	Implicit numerical scheme Newton iteration weighting factor. A Larger value tends to increase stability, but at the cost of performance. We suggest using the default value or values between 0.6 and 0.85, but values between 0.1 and 1.0 are valid. Use 0.98 - 1.0 in very difficult cases.
Relaxation Weighting Coefficient	The weighting coefficient used by the relaxation equation for estimating lateral flow. The values must range between 0 and 1.
Computational Distance	Implicit numerical scheme computational distance interval. The model will automatically insert additional computational sections based on this value, a small value increases stability while large value increases performance. Computational distance is the lesser of one half the pipe length or default distance.
Virtual Flow Depth	This is an option used in the implicit solver to overcome the calculation instabilities when the conduit is in dry (zero flow) or the flow is very small.
Neglect Side Flow?	If True, only frontal views will be included in the inlet calculations.
Active Components for Combination Inlets In Sag	This section gives you the choice of whether to use both curb and grate openings or the grate or curb opening only for combination inlets in sag.
Active Components for Combination Inlets On Grade	This section gives you the choice of whether to use both curb and grate openings or the grate or curb opening only for combination inlets on grade.
Neglect Gutter Cross Slope For Side Flow?	If True, when grate width is less than gutter width, gutter cross slope is used to determine side flow.