Openturns for Telemac2D result file sensitivity analysis

Question

I used the Telemac2D software to solve the Shallow Water Equations and got 1000 result files that i want now to post-treat and do some sensitivity analysis with OpenTURNS. The output i mainly want to focus on is the water level. In my case, i can have it's value for different time steps.

My problem is the way of linking the inputs to the output of interest in order to launch a polynomial chaos algorithm, since i don't have an explicit representation of the output by the input (if i had it i could use ot.SymbolicFunction or PythonFunction).

Answer 1

In the case where the inputs and outputs are known only from a Sample, we may use the following constructor:

chaosalgo = ot.FunctionalChaosAlgorithm(inputTrain, outputTrain)

where inputTrain is the input Sample and outputTrain is the output Sample. The two samples must have the same size (but not necessarily the same dimension). In this case, the library performs several steps before fitting the polynomial chaos:

• it fits the multivariate distribution depending on the inputTrain Sample,
• it creates the multivariate basis depending on the input distribution,
• then it computes the coefficients of the polynomial chaos based on regression.

This way of creating the chaos is presented in the following page: Fit a distribution from an input sample.