Dakota Reference Manual  Version 6.16
Explore and Predict with Confidence
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Aleatory uncertain variable - triangular


This keyword is related to the topics:


Alias: none

Argument(s): INTEGER

Default: no triangular uncertain variables

Child Keywords:

Required/Optional Description of Group Dakota Keyword Dakota Keyword Description
Required modes Distribution parameter
Required lower_bounds Specify minimum values
Required upper_bounds Specify maximium values
Optional initial_point

Initial values for variables

Optional descriptors

Labels for the variables


The triangular distribution is often used when one does not have much data or information, but does have an estimate of the most likely value and the lower and upper bounds. The number of triangular uncertain variables, the modes, and the distribution lower and upper bounds are required specifications, whilevariable descriptors is an optional specification.

The density function for the triangular distribution is:

\[f(x) = \frac{2(x-L)}{(U-L)(M-L)}\]

if $L\leq x \leq M$, and

\[f(x) = \frac{2(U-x)}{(U-L)(U-M)}\]

if $M\leq x \leq U$, and 0 elsewhere. In these equations, $L$ is the lower bound, $U$ is the upper bound, and $M$ is the mode of the triangular distribution.