"如何提高数组 max、min、mean 和 std dev 的多个统计数据的性能（并行化或其他想法）计算？"

Question

this is a continuation of this post<\/a> . I must calculate many times some statistics(Max, mean, min, median and std dev) of arrays and I have a performance issue given the sort of my arrays in the method calcMaxMinMedian.

Time (s) functionUsingForLoop173
Time (s) functionUsingParallelStream194

Answer 1

Part of your issue is that you are computing your randomised the data samples inside the tests, but have contention with the singleton random number generation in parallel threads. Also this means that you have no means of validating that the parallel algorithm matches the serial results.

private double[][] generateInputData(int numVals, int numCalculations) {
    // calculations that is used to get some values, but is not modified.
    double[][] inputs = new double[numCalculations][];// Each
    for (int i = 0; i < numCalculations; i++) {
        inputs[i] = functionSimulateCalculations(numVals);
    }
    return inputs;
}