调整搜索空间 API

本节介绍您可以用来定义搜索空间的功能。

小心

并非所有搜索算法都支持所有分布。特别是，tune.sample_from 和 tune.grid_search 通常不受支持。默认的 随机搜索和网格搜索 (tune.search.basic_variant.BasicVariantGenerator) 支持所有分布。

小技巧

避免在搜索空间中传递大型对象作为值，因为这会导致性能开销。使用 tune.with_parameters 来传递大型对象，或者从磁盘（确保所有节点都能访问文件）或云存储中加载它们。更多信息请参见 我如何避免瓶颈？。

对于一个高层次的概述，请看这个例子：

config = {
    # Sample a float uniformly between -5.0 and -1.0
    "uniform": tune.uniform(-5, -1),

    # Sample a float uniformly between 3.2 and 5.4,
    # rounding to multiples of 0.2
    "quniform": tune.quniform(3.2, 5.4, 0.2),

    # Sample a float uniformly between 0.0001 and 0.01, while
    # sampling in log space
    "loguniform": tune.loguniform(1e-4, 1e-2),

    # Sample a float uniformly between 0.0001 and 0.1, while
    # sampling in log space and rounding to multiples of 0.00005
    "qloguniform": tune.qloguniform(1e-4, 1e-1, 5e-5),

    # Sample a random float from a normal distribution with
    # mean=10 and sd=2
    "randn": tune.randn(10, 2),

    # Sample a random float from a normal distribution with
    # mean=10 and sd=2, rounding to multiples of 0.2
    "qrandn": tune.qrandn(10, 2, 0.2),

    # Sample a integer uniformly between -9 (inclusive) and 15 (exclusive)
    "randint": tune.randint(-9, 15),

    # Sample a random uniformly between -21 (inclusive) and 12 (inclusive (!))
    # rounding to multiples of 3 (includes 12)
    # if q is 1, then randint is called instead with the upper bound exclusive
    "qrandint": tune.qrandint(-21, 12, 3),

    # Sample a integer uniformly between 1 (inclusive) and 10 (exclusive),
    # while sampling in log space
    "lograndint": tune.lograndint(1, 10),

    # Sample a integer uniformly between 1 (inclusive) and 10 (inclusive (!)),
    # while sampling in log space and rounding to multiples of 2
    # if q is 1, then lograndint is called instead with the upper bound exclusive
    "qlograndint": tune.qlograndint(1, 10, 2),

    # Sample an option uniformly from the specified choices
    "choice": tune.choice(["a", "b", "c"]),

    # Sample from a random function, in this case one that
    # depends on another value from the search space
    "func": tune.sample_from(lambda spec: spec.config.uniform * 0.01),

    # Do a grid search over these values. Every value will be sampled
    # ``num_samples`` times (``num_samples`` is the parameter you pass to ``tune.TuneConfig``,
    # which is taken in by ``Tuner``)
    "grid": tune.grid_search([32, 64, 128])
}

随机分布 API

tune.uniform	在 lower 和 upper 之间均匀采样一个浮点值。
tune.quniform	在 lower 和 upper 之间均匀采样一个量化的浮点值。
tune.loguniform	用于按不同数量级采样的工具。
tune.qloguniform	用于按不同数量级采样的工具。
tune.randn	使用 mean 和 sd 从正态分布中采样一个浮点值。
tune.qrandn	使用 mean 和 sd 从正态分布中采样一个浮点值。
tune.randint	在 lower 和 upper 之间均匀采样一个整数值。
tune.qrandint	在 lower 和 upper 之间均匀采样一个整数值。
tune.lograndint	在 lower 和 upper 之间对整数值进行对数均匀采样，其中 base 是对数的底数。
tune.qlograndint	在 lower 和 upper 之间对整数值进行对数均匀采样，其中 base 是对数的底数。
tune.choice	采样一个分类值。

网格搜索和自定义函数API

tune.grid_search	指定一个值的网格以进行搜索。
tune.sample_from	指定tune应从此函数中采样配置值。

参考文献

另请参阅 随机搜索和网格搜索 (tune.search.basic_variant.BasicVariantGenerator)。