如何平衡输入到这个有向图的输出?

时间:2017-08-13 18:45:07

标签: algorithm graph-theory graph-algorithm

我想到的图表类型非常具体。我已经为它提出了自己的名字:Iode(EYE-ode)。
这是" I / O"和电子术语"阳极"和"阴极"。

IODE

Iode从其关联的输入节点中获取大量项目,并将项目均匀地分配到其关联的输出节点。

  • 可能有1到N个输入节点。
  • 可能有1到M个输出节点。
  • 组合输入节点的边缘,然后将其拆分为输出节点。
  • 输出节点永远不会连接到输入节点。
  • 当Iode" ticks"它在相关节点上进行平衡操作。
  • 每个节点每个节点的最大输入。
  • 每个节点的每个节点的最大输出。
  • 每个刻度的最大总吞吐量。

这是一个如何连接事物的图表(使用http://pencil.evolus.vn/): iode_simple_cases

每个方格都是一个节点。每个节点都可以包含一些数字。

我对Iode tick的算法有困难。我想最大化吞吐量,这可能在很多方面受到限制。

这是我在github(https://github.com/voxelv/ioder)上的初始python尝试,特别是在algorithms.py中:

def iode_int_tick(iode):
    # Get the amounts per input iode node
    input_amount_per_iode_node = []
    for iode_node in iode.input_nodes:
        input_amount_per_iode_node.append(min(iode_node.amount, iode.speed['input']))

    # Get the amounts per output iode node
    output_amount_per_iode_node = []
    for iode_node in iode.output_nodes:
        output_amount_per_iode_node.append(iode.speed['output'])

    # Get the maximum throughput
    max_thru_speed = int(iode.speed['throughput'])
    input_amount_total = sum(input_amount_per_iode_node)
    output_amount_total = sum(output_amount_per_iode_node)

    # Compare the maximum throughput
    diff_input_thru_max = int(input_amount_total - max_thru_speed)
    diff_output_thru_max = int(output_amount_total - max_thru_speed)

    # Lessen the input if the maximum throughput is smaller
    if diff_input_thru_max > 0:
        for i in xrange(len(iode.input_nodes)):
            pass  # TODO: figure out this

    # Lessen the output if the maximum throughput is smaller
    if diff_output_thru_max > 0:
        for i in xrange(len(iode.input_nodes)):
            pass  # TODO: figure out this

    # Move the numbers from the inputs
    for i, inode in enumerate(iode.input_nodes):
        inode.take(input_amount_per_iode_node[i])

    # Move the numbers into the outputs
    for i, inode in enumerate(iode.output_nodes):
        inode.give(output_amount_per_iode_node[i])

我试图找出具有# TODO条评论的for循环内容。

编辑:将一个示例加载到main.py和config.py中 每个节点的输入限制为5 每个节点的输出限制为5
最大吞吐量为8

因此,如果将两个输入设置为23和6,将两个输出设置为4和0,则滴答后的预期结果将是输入节点中的19和2,以及输出节点中的8和4。

使用python main.py运行代码会产生以下输出:

Actual:   [18, 1], [9, 5]
Expected: [19, 2], [8, 4]

更多例子:

Initial:  [22, 2], [3, 20]
Actual:   [17, 0], [8, 25]
Expected: [17, 0], [7, 23] or [17, 0], [6, 24]

根据处理剩余部分的顺序,预期可以是所提到的任何一个。最大吞吐量将我们限制为8,但每个节点的最大输入限制我们从第一个输入节点取5。由于第二个输入节点只有两个,因此我们只能为此刻度提供7个。 7尽可能均匀地分配到输出,第一个输出中有3个或4个,第二个输出中有4个或3个。

1 个答案:

答案 0 :(得分:0)

我想出了我的问题的类比,并且能够通过类比更好地理解它。

这就像试图用水填充冰块托盘一样。

我构建Iode的方式,将永远不会有更多的水,而不是托盘可以处理。

这是我的解决方案:

def water_into_ice_tray(water, ice_tray, **kwargs):

    water_to_put = [0 for _ in xrange(len(ice_tray))]
    recursion_ice_tray = [x for x in ice_tray]

    # Debug depth
    if 'depth' in kwargs:
        print kwargs['depth'],
        kwargs['depth'] += 1

    # BASE_CASE: No more water
    if not water > 0:
        # Exit early
        return water_to_put

    # Get slots that have space for more water
    open_slots = []
    for i in xrange(len(ice_tray)):
        if ice_tray[i] > 0:
            open_slots.append(i)

    # BASE_CASE: Not enough water to go around
    if water < len(open_slots):
        # Put 1 more in the first 'water' slots
        for i in xrange(water):
            water_to_put[open_slots[i]] += 1
        # Exit early
        return water_to_put

    # BASE_CASE: Too much water
    if water > sum(ice_tray):
        raise ValueError("Too much water")

    # Attempt to fill each open slot with a distributed amount
    fill_amount = int(math.floor(int(water) / len(open_slots)))
    leftover = int(water) % len(open_slots)
    for slot_index in open_slots:
        # With how much water have we overfilled this slot?
        diff = fill_amount - ice_tray[slot_index]

        if diff >= 0:
            # We tried putting too much water into this slot
            # Calculate how much to put in it
            water_to_put[slot_index] += fill_amount - diff
            # No more water can fit into this slot
            recursion_ice_tray[slot_index] = 0
            # Keep the leftover
            leftover += diff
        else:
            # The slot could hold the water
            water_to_put[slot_index] += fill_amount
            # Some more water can fit into this slot
            recursion_ice_tray[slot_index] = -diff
            # None is leftover

    # Recurse
    recursion_water_to_put = water_into_ice_tray(leftover, recursion_ice_tray, **kwargs)

    # Add up recursion result to this result
    return map(add, water_to_put, recursion_water_to_put)


def iode_int_tick(iode):
    # Calculate available amounts per input node
    available_input_per_node = []
    for inode in iode.input_nodes:
        available_input_per_node.append(min(inode.amount, iode.speed['input']))
    input_limit = sum(available_input_per_node)

    # Get the throughput
    throughput_limit = iode.speed['throughput']

    # Calculate available space per output node
    available_output_per_node = []
    for inode in iode.output_nodes:
        available_output_per_node.append(min(inode.max_amount - inode.amount, iode.speed['output']))
    output_limit = sum(available_output_per_node)

    # Decide which is the limiting factor
    limiter = min(input_limit, throughput_limit, output_limit)

    if limiter == input_limit:
        # If the input limits, then distribute to the outputs. The throughput can handle it.
        amount_to_take_per_input_node = available_input_per_node
        amount_to_put_per_output_node = water_into_ice_tray(input_limit, available_output_per_node)
        pass

    elif limiter == throughput_limit:
        # If throughput limits, then distribute the throughput amount from the inputs, to the outputs.
        amount_to_take_per_input_node = water_into_ice_tray(throughput_limit, available_input_per_node)
        amount_to_put_per_output_node = water_into_ice_tray(throughput_limit, available_output_per_node)
        pass

    elif limiter == output_limit:
        # If output limits, then distribute the draw on the inputs. The throughput can handle it.
        amount_to_take_per_input_node = water_into_ice_tray(output_limit, available_input_per_node)
        amount_to_put_per_output_node = available_output_per_node
        pass
    else:
        raise ValueError("Somehow the limiting factor is something other than the input, throughput, or output.")

    # Do the taking
    for i in xrange(len(iode.input_nodes)):
        iode.input_nodes[i].take(amount_to_take_per_input_node[i])

    # Do the giving
    for i in xrange(len(iode.output_nodes)):
        iode.output_nodes[i].give(amount_to_put_per_output_node[i])