求教定时任务问题。

2017-06-29 07:18:49 149 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

嵌套交叉验证的‘双循环’哲学：为什么你的模型评估总是不准？本文深入探讨了嵌套交叉验证（Nested Cross-Validation）在机器学习模型评估中的关键作用，揭示了传统交叉验证方法存在的偏差问题。通过双重循环设计，嵌套交叉验证有效隔离数据，提供无偏评估，显著提升模型在真实场景中的性能预测准确性。文章还提供了工程实践中的优化策略和量化分析，帮助开发者在计算成本与评估精度之间找到平衡。阅读详情

private void sched(TimerTask task, long time, long period) {

        if (time < 0)

            throw new IllegalArgumentException("Illegal execution time.");



        // Constrain value of period sufficiently to prevent numeric

        // overflow while still being effectively infinitely large.

        if (Math.abs(period) > (Long.MAX_VALUE >> 1))

            period >>= 1;



        synchronized(queue) {

            if (!thread.newTasksMayBeScheduled)

                throw new IllegalStateException("Timer already cancelled.");



            synchronized(task.lock) {

                if (task.state != TimerTask.VIRGIN)

                    throw new IllegalStateException(

                        "Task already scheduled or cancelled");

                task.nextExecutionTime = time;

                task.period = period;

                task.state = TimerTask.SCHEDULED;

            }



            queue.add(task);

            if (queue.getMin() == task)

                queue.notify();

        }

    }