System Reports

System reports provide information related to the running of the simulation.

No scalar is selected, and no input parts need be defined. When one of these reports is added to the report manager node, it is removed from the pop-up menu of that node, as you only require one instance of each system report.

System Report Properties
  • Units—units that are used for specifying the quantity.
AMG Cycles
This report returns the number of cycles that the Coupled Implicit Solver's AMG linear solver takes at each solver iteration to solve the discrete system. This solution is used to update the independent variables, Pressure, Velocity and Temperature (or Enthalpy).
Iterations per Time Step
Reports the number of inner iterations taken within each time-step. This report is available only for unsteady Eulerian Multiphase (EMP) simulations.
Courant Number
This report returns the current Courant Number (CFL) which the Coupled Implicit Solver uses. Note that CFL can be a constant when Constant CFL is selected in the Coupled Implicit Solver properties, or it can be a value that can change from iteration to iteration when either Linear Ramp, Expert Driver, or AutomaticCFL methods are selected.
Explicit Relaxation
This report returns the current iteration value of the Coupled Implicit solver explicit relaxation factor, E-URF. Again, that can be a constant value when the Constant method is selected (or None, in which case the value is 1.0), or it can change from iteration to iteration when the Line-Search method is selected in the CIS properties panel.
Lagrange Multiplier

This report returns the Lagrange multiplier associated with the topology optimization constraints.

This report is available only with the Adjoint Topology Optimization model. The Lagrange multiplier estimate is defined as λ i k in Eqn. (5132), and it is used to monitor if the topology optimization objective has been minimized/maximized and the constraints are satisfied. When the constraint specific criteria are met, the Lagrange multiplier estimate should converge to a specific fixed value (a value where the augmented Lagrangian problem is equivalent to the initial constraint problem), and remain constant with further iterations. All Lagrange multipliers need to be converged when all constraints are satisfied.

Lagrange Multiplier Report Properties
  • Constraint—selects the adjoint topology optimization constraint.
Memory Report

The Memory Report returns the memory usage of Simcenter STAR-CCM+.

Under the Memory Report there are options to return different memory metrics:

  • Virtual
  • Resident
  • Virtual High Water Mark
  • Resident High Water Mark

The high-water-mark (HWM) values essentially return the peak memory usage during the life of the simulation. The HWM values should never decrease during the simulation. In Simcenter STAR-CCM+ the memory peaks of different parallel simulation processes should be reached at similar times and the accumulated HWM values should be a good estimate of the global high-water-mark.

The other metrics return the peak during each iteration.

The peak-per-iteration values incur a small performance penalty due to the necessary sampling of the memory metric from the system (in a manner similar to well-known system tools).

The HWM metrics do not require constant sampling and do not impose any additional performance penalty.

On Linux there are some important well known limitations of the memory metrics available. The memory metrics extracted for each process include resources that are shared between processes. When accumulating per-process metrics, shared resources are accounted multiple times and thus the accumulated values overestimate the true memory usage. This is particularly acute when measuring Virtual memory use but even the Resident values are overestimated.

When using GPGPUs with MPS (see Using MPS), the GPGPU Resident Memory Report only shows correct measurements on NVIDIA Volta and newer architectures. For other architectures, the reported memory usage is zero.

Memory Report Properties
Units
Units that are used for specifying the quantity.
Metric Type
Allows you to select a type of memory metric.
  • Virtual—the maximum virtual memory that is accumulated across all processes per iteration.
  • Resident—the maximum physical memory (RAM) that is accumulated across all processes per iteration.
  • Virtual High Water Mark—The accumulated virtual high water mark across all processes.
  • Resident High Water Mark—The accumulated resident high water mark across all processes.
Sampling Frequency
The frequency at which the system is probed for memory consumption. Applies to all memory reports. This setting is useful for extracting "maximum per iteration" values (Virtual, Resident).
The frequency has been set to minimize the cost of the sampling while still returning accurate values. Increasing the sampling frequency will increase the granularity of the sampling and thus make it more accurate, but it will also increase the cost of the sampling. Conversely reducing the sampling frequency will reduce the accuracy and decrease the cost of the sampling. You are advised to modify this value only if you have expert understanding of the implications.
Physics Continuum Iteration
Number of iterations for which the physics continuum designated for the report has been active.
Physics Continuum Physical Time
Duration of physical time for which the physics continuum designated for the report has been active.
PISO Correctors Report

Reports the number of PISO corrector steps taken witih each time-step.

Available only with the PISO Unsteady model. When this model is selected, the Maximum PISO Correctors and PISO Residual Reduction criteria are added under Stopping Criteria and the PISO Correctors Report is added under Reports. Monitors and plots can be created from reports.

The Maximum PISO Correctors criterion allows you to set Maximum PISO Correctors allowed in an iteration. The default is 20.

The PISO Residual Reduction criterion allows you to set Minimum PISO Correctors required per iteration (default of 2) and PISO Residual Reduction (default of 0.25).

Solver Iteration CPU Time
The solver CPU time is the accumulated CPU time for all processes for the last iteration executed.
Solver Iteration Elapsed Time
The solver elapsed time shows how long it took to execute the last iteration.
Solver CPU Time Per Time-Step
The solver CPU time is the accumulated CPU time for all processes, per time-step (for unsteady simulations), for the last time-step executed.
Solver Elapsed Time Per Time-Step
The solver elapsed time shows how long it took to execute the last time-step (for unsteady simulations).
Total Solver CPU Time
The total solver CPU time is the accumulated CPU time for all processes. Clearing the solution resets the total CPU time to zero.
Total Solver Elapsed Time
The total solver elapsed time is the cumulative time taken to run the entire solution. Clearing the solution resets the total solver elapsed time to zero.