def _getRun(self, functionName, resultName, rank=0.0):
results = self.getFunctionResults(functionName, [resultName])
runs = []
pareto = self.getFunctionPareto(functionName)
metrics = Metrics(pareto, [results[0][1]])
for run in xrange(len(results[0][1])):
metrics.setSolutionsToCompare(0, run, None, None)
value = metrics.deltaP()
runs.append([value, run])
runs.sort(key = lambda x : x[0])
idx = max(0, int(round(len(runs) * rank)) - 1)
return runs[idx][1]
