Python 重复约束优化
我有一组(10000+个)项目,我必须从中选择正确的Python 重复约束优化,python,or-tools,Python,Or Tools,我有一组(10000+个)项目,我必须从中选择正确的k项目。我只能根据顺序限制多次选择每个项目:如果我在位置1选择一个项目,我在位置21之前无法选择它。我的物品有利润,也有成本 每个项都表示为一个元组: item = ('item name', cost, profit) 例如 vase = ['Ming Vase', 1000, 10000] plate = ['China Plate', 10, 5] 项目的总集是一个列表: items = [item1, item2, ..., it
k
项目。我只能根据顺序限制多次选择每个项目:如果我在位置1选择一个项目,我在位置21之前无法选择它。我的物品有利润,也有成本
每个项都表示为一个元组:
item = ('item name', cost, profit)
例如
vase = ['Ming Vase', 1000, 10000]
plate = ['China Plate', 10, 5]
项目的总集是一个列表:
items = [item1, item2, ..., itemN].
我的利润和成本也列出了:
profits = [x[2] for x in items]
costs = [x[1] for x in items]
对于选择的每个项目,它需要有一个最小值,并且该项目不能在接下来的19个项目中重复使用。我想根据这个约束选择k个最便宜、价值最高的项目,但我很难确定它
我很难用谷歌或其他工具来描述这一点。下面只得到最佳的k
(在本例中为100),没有任何额外的约束
from ortools.linear_solver import pywraplp
solver = pywraplp.Solver('SolveAssignmentProblemMIP',
pywraplp.Solver.CBC_MIXED_INTEGER_PROGRAMMING)
x = {}
for i in range(MAX_ITEMS):
x[i] = solver.BoolVar('x[%s]' % (i))
#Define the constraints
total_chosen = 100
solver.Add(solver.Sum([x[i] for i in range(MAX_ITEMS)]) == total_chosen)
max_cost = 5.0
for i in range(num_recipes):
solver.Add(x[i] * cost[i] <= max_cost)
solver.Maximize(solver.Sum([profits[i] * x[i] for i in range(total_chosen)]))
sol = solver.Solve()
在制定约束条件和目标方面的任何帮助都会非常有用。谢谢
solver.Add(x[i] * cost[i] <= max_cost)
如果没有其他限制,该目标要求选择最佳项目total_selected
次数。但我们不能重复太多的项目。因此,我们需要20个成本低于max\u cost
的最佳项目,并重复它们total\u selected/20次
import numpy
MAX_ITEMS = 10000
cost = numpy.random.randint(1, 100, MAX_ITEMS)
profits = numpy.random.randint(1, 100, MAX_ITEMS)
total_chosen = 100
repeat = 20
max_cost = 5.0
cheap = [i for i in range(MAX_ITEMS) if costs[i] <= max_cost]
chosen = sorted(cheap, key=lambda i: profits[i], reverse=True)[:repeat]
for _ in range(total_chosen/repeat):
for i in chosen:
print(i, costs[i], profits[i])
导入numpy
最大项目数=10000
成本=numpy.random.randint(1100个,最多个项目)
利润=numpy.random.randint(1100个,最大项)
所选总数=100
重复=20次
最大成本=5.0
便宜=[i for i in range(MAX_ITEMS)如果花费[i]一个想法,如果你为前20个对象创建了一个最佳解决方案,你能重复这个模式直到序列结束吗
如果是,请按20个最佳值对项目进行排序,然后重复该顺序。首先,您需要严格地制定“k个最便宜的项目,具有最高值”。因为有十几个数学公式。您可以尝试优化总和、最大/最小值、顺序,对总和或最大/最小值施加约束,对每个标准计算relative值划分标准等。似乎您可以从表单中排除重复约束。乍一看,如果您可以重复某个项目,则必须重复。因此,您只需要分配前19(20?)个项目,以后(最佳)序列应复制前19个。对于范围内的i(num_配方):解算器。添加(x[i]*成本[i]
Sum([profits[i] * x[i])
import numpy
MAX_ITEMS = 10000
cost = numpy.random.randint(1, 100, MAX_ITEMS)
profits = numpy.random.randint(1, 100, MAX_ITEMS)
total_chosen = 100
repeat = 20
max_cost = 5.0
cheap = [i for i in range(MAX_ITEMS) if costs[i] <= max_cost]
chosen = sorted(cheap, key=lambda i: profits[i], reverse=True)[:repeat]
for _ in range(total_chosen/repeat):
for i in chosen:
print(i, costs[i], profits[i])
import numpy
from ortools.linear_solver import pywraplp
solver = pywraplp.Solver('SolveAssignmentProblemMIP',
pywraplp.Solver.CBC_MIXED_INTEGER_PROGRAMMING)
MAX_ITEMS = 10000
costs = numpy.random.randint(1,100,MAX_ITEMS)
profits = numpy.random.randint(1,100,MAX_ITEMS)
total_chosen = 100
repeat = 20
max_cost = 5.0
x = {}
for i in range(MAX_ITEMS):
x[i] = solver.BoolVar('x[%s]' % (i))
solver.Add(solver.Sum([x[i] for i in range(MAX_ITEMS)]) == repeat)
for i in range(MAX_ITEMS):
solver.Add(x[i] * costs[i] <= max_cost)
solver.Maximize(solver.Sum([profits[i] * x[i] for i in range(MAX_ITEMS)]))
sol = solver.Solve()
for i in range(MAX_ITEMS):
if x[i].solution_value() > 0:
print(i, profits[i], costs[i])