Ishigami Function

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Problem definition

An external C program is provided that compute the output of the Ishigami function:

f(x_1,x_2,x_3) = \sin(x_1) + a \sin^2 (x_2) + b x_3^4 \sin(x_1)

The Ishigami function of Ishigami & Homma (1990) is used as an example for uncertainty and sensitivity analysis methods, because it exhibits strong nonlinearity and nonmonotonicity. It also has a peculiar dependence on  x_3 .

Input data

Parameter a = 7

Parameter b = 0.05

Function input  x_1: uniform with lower bound  -\pi , upper bound  \pi .

Function input  x_2: uniform with lower bound  -\pi , upper bound  \pi .

Function input  x_3: uniform with lower bound  -\pi , upper bound  \pi .

Aim of the Tutorial

The aim of the tutorial is to show how to connect a third party solver to COSSAN-X.

Prerequisite

Compile the c file ishigamiFunction.c in OpenSourceSoftware/src/ishigamiFunction with the command:

Linux and MacOS X

  gcc ishigamiFunction.c ini.c -lm -o ishigamiFunction

Windows (requires a gcc installation, e.g., tdm-gcc-64

  gcc ishigamiFunction.c ini.c -lm -o ishigamiFunction.exe

Download pre-compiled function for Linux here: File:IshigamiFunction.zip.

See Also