====== Probabilistic settings ======

Before starting a probabilistic simulation there are certain settings to make. The minimum is to select which parameters to include in the probabilistic analysis. Select **Simulation | Probabilistic Settings** from the main menu or press F7 to set probabilistic settings.

===== General =====

**Number of simulations** - This setting specifies how many simulations will be performed during a probabilistic simulation. //Default value = 1000//

**Seed** - Initialises the seed value for the random number generator. If you set the same seed, then the sequence will be the same each run.

**Sampling** - Specifies the type of sampling used during the simulation, either Monte Carlo or Latin Hypercube sampling.

===== Parameters =====

This page lets you select the [[Parameter|parameters]] that will be included in the analysis. Only parameters that have been assigned [[PDF|probability density functions]] can be selected.

Note that you must select at least one parameter to run a probabilistic simulation.

===== Correlation =====

Correlations between parameters can be assigned in order to reduce noise and to avoid impossible parameter combinations.

A probabilistic simulation starts with sampling values for all the probabilistic parameters, using either a (random) Monte Carlo scheme or Latin Hypercube sampling.

After the values are sorted so that correlated parameter values are used in the same iteration. For example, consider the parameters //weight// and //height//. These parameters are log-normally distributed and are positively correlated, meaning that it is common for heavy humans to also be tall. By assigning a correlation of say 0.5, the likelyhood of the weight parameter being large in the same iteration as the height parameter is large will increase.

To add correlations you must first select the **Enabled** button. You then click the **Add** button for each parameter pair, select the two parameters from the left and right lists and enter a correlation between the two.

===== See also =====

  * [[Probabilistic_analysis|Probabilistic analysis]]