RP53 analysis and 2D graphics

The objective of this example is to present problem 53 of the BBRC. We also present graphic elements for the visualization of the limit state surface in 2 dimensions.

import openturns as ot
import openturns.viewer as otv
import otbenchmark as otb
problem = otb.ReliabilityProblem53()
event = problem.getEvent()
g = event.getFunction()
problem.getProbability()
0.0313

Create the Monte-Carlo algorithm

algoProb = ot.ProbabilitySimulationAlgorithm(event)
algoProb.setMaximumOuterSampling(1000)
algoProb.setMaximumCoefficientOfVariation(0.01)
algoProb.run()

Get the results

resultAlgo = algoProb.getResult()
neval = g.getEvaluationCallsNumber()
print("Number of function calls = %d" % (neval))
pf = resultAlgo.getProbabilityEstimate()
print("Failure Probability = %.4f" % (pf))
level = 0.95
c95 = resultAlgo.getConfidenceLength(level)
pmin = pf - 0.5 * c95
pmax = pf + 0.5 * c95
print("%.1f %% confidence interval :[%.4f,%.4f] " % (level * 100, pmin, pmax))
Number of function calls = 1000
Failure Probability = 0.0280
95.0 % confidence interval :[0.0178,0.0382]
inputVector = event.getAntecedent()
distribution = inputVector.getDistribution()
X1 = distribution.getMarginal(0)
X2 = distribution.getMarginal(0)
alpha = 1 - 1.0e-4
bounds, marginalProb = distribution.computeMinimumVolumeIntervalWithMarginalProbability(
    alpha
)
_ = otv.View(X1.drawPDF())
plot rp53

Draw the limit state surface

graph = drawEvent.drawLimitStateCrossCut(bounds)
graph.add(cloud)
_ = otv.View(graph)
Limit state surface
domain = drawEvent.fillEventCrossCut(bounds)
_ = otv.View(domain)
Domain where g(x) < 0.0
domain.add(cloud)
_ = otv.View(domain)
Domain where g(x) < 0.0
otv.View.ShowAll()

Total running time of the script: (0 minutes 1.839 seconds)