Probabilistic tools in OpenEarth Example with Van der Meer formula Kees den Heijer, TU Delft & Deltares
Overview Probabilistic calculation Relevant Matlab tools Stochastic variables Limit state function (Z-function) Reliability method (FORM, Monte Carlo) Relevant Matlab tools OpenEarthTools CT4310 release as zip-file OpenEarthTools full version via subversion
Stochast variable Structure with fields: Name Distr Params Unique name for each stochastic variable Distr Functionhandle of distribution function (e.g. @norm_inv) Params Parameters in cell-array as input for the corresponding distribution function propertyName Indicate how to parse variable to z-function
Distribution should be matlab functionhandle Stochast variable Names are custom Distribution should be matlab functionhandle Params are second and further input arguments of the distribution function Distr Params
Available distribution functions Functionhandle Parameters Normal @norm_inv mu, sigma Exponential @exp_inv lambda, epsilon Triangular @trian_inv a, b, c Lognormal @logn_inv Uniform @unif_inv a, b Conditional Weibull @conditionalWeibull omega, rho, alpha, sigma Deterministic @deterministic x
Limit state function This should be created as separate function Input arguments: samples : specified as propertyName-propertyValue pairs Output argument: z : z-values corresponding to the x-values
Limit state function Calculate Z
Run calculation General Monte Carlo Additional settings: Specify stochast variable with: ‘stochast’, stochast_variable Specify z-function with: ‘x2zFunction’, @your_custom_zfunction Monte Carlo Specify number of samples with: ‘NrSamples’, 1e4 Additional settings: Next arguments are optional combinations of keywords and corresponding values (propertyName-propertyValue pairs)
Run calculation
Monte Carlo defaults
FORM defaults
Preparation Release with relevant tools available via Blackboard Download and unzip the file CT4310_release.zip Start Matlab Activate tools by running: \CT4310_release\oetsettings.m
Example calculation Example calculation with Van der Meer formula available under:
FAQ Only the Monte Carlo output is available, how do I get the FORM results? Monte Carlo seems to work properly, but FORM gives an error.
Only the Monte Carlo output is available, how do I get the FORM results? (1)
Only the Monte Carlo output is available, how do I get the FORM results? (2)
Monte Carlo seems to work properly, but FORM gives an error. This message means that complex numbers are found by the z-function. Solution: check whether your z-function probably in an unfavorable combination of stochastic variable values could lead to complex numbers… Please note: if so, although Monte Carlo still gives a result, this is not reliable.
Full OpenEarthTools repository A wide variety of tools Including the tools relevant for this assignment Matlab and other languages Useful for MSc thesis project Useful for your future job Requirements: Username and password: register at http://oss.deltares.nl Subversion client (e.g. TortoiseSVN) About 1Gb disk space
Delft3D
JarKus transects
OpenEarth.nl