ishigami_Fun {sensobol}

Ishigami function

Description

It implements the Ishigami and Homma (1990) function.

Usage

ishigami_Fun(X)

Arguments

X

A data frame or numeric matrix where each column is a model input and each row a sample point.

Details

The function requires 3 model inputs and reads as

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

where a=2, b=1 and (x_1,x_2,x_3)\sim\mathcal{U}(-\pi, +\pi). The transformation of the distribution of the model inputs from U(0, 1) to U(-\pi, +\pi)) is conducted internally.

Value

A numeric vector with the model output.

References

Ishigami T, Homma T (1990). “An importance quantification technique in uncertainty analysis for computer models.” Proceedings. First International Symposium on Uncertainty Modeling and Analysis, 12, 398–403.

Examples

# Define settings
N <- 100; params <- paste("X", 1:3, sep = "")

# Create sample matrix
mat <- sobol_matrices(N = N, params = params)

# Compute Ishigami function
Y <- ishigami_Fun(mat)