Contents
Additive measurement model
The measurement model is the additive model
This function evaluates the model for values of the input quantities and (optionally) calculates sensitivity coefficients. The input to the function is a matrix x of N rows and M columns containing M sets of values of the N input quantities in the model. The function returns in y the M values of the output quantity, with the rth value formed by evaluating the model for the values of the input quantities in the rth column of x.
When M = 1, the function returns in c the N sensitivity coefficients, which are all equal to one for this model.
In an application of the GUM uncertainty framework, the function is called with M = 1 and x contains the estimates of the input quantities. In an application of the Monte Carlo method, the function is called with M equal to the number of Monte Carlo trials, and the rth column of x contains random draws from the probability distributions for the input quantities corresponding to the rth Monte Carlo trial.
See sections 3, 4.2 and 5.4.1 of M G Cox, P M Harris and I M Smith, Software specifications for uncertainty evaluation, 2010.
function [y, c] = model_additive(x)
Input
x N x M Values of the input quantities
Output
y 1 x M Values of the output quantity c 1 x N Sensitivity coefficients (for the case M = 1)
Use the size of x to obtain values for N and M.
[N, M] = size(x);
Form values of the output quantity.
if N == 1 y = x; else y = sum(x); end
Form values of the sensitivity coefficients (for the case M = 1).
if M == 1 c = ones(1,N); end
Program identifier
NPLUnc_101 Open-Source Software (Release 1.1): Software for measurement uncertainty evaluation
M G Cox, P M Harris and I M Smith, Mathematics and Scientific Computing Group, National Physical Laboratory, UK
Crown copyright 2011