摘要：運(yùn)籌做為一個(gè)運(yùn)籌人多少知道些仿真優(yōu)化軟件當(dāng)然高階的運(yùn)籌實(shí)踐一定是以代碼為基礎(chǔ)的無(wú)論用什么代碼最終也是在代碼中首先建立所要優(yōu)化問(wèn)題的抽象模型一般都是一個(gè)優(yōu)化問(wèn)題如果你會(huì)的話就可以無(wú)障礙閱讀接下來(lái)的內(nèi)容如果你不會(huì)的話花半天時(shí)間學(xué)一下再來(lái)準(zhǔn)備工作

做為一個(gè)運(yùn)籌人,多少知道些仿真/優(yōu)化軟件,當(dāng)然,高階的運(yùn)籌實(shí)踐一定是以代碼為基礎(chǔ)的,無(wú)論用什么代碼,最終也是在代碼中首先建立所要優(yōu)化問(wèn)題的抽象模型,一般都是一個(gè)優(yōu)化問(wèn)題：

$$ minimize f_0(x) $$ $$ subject to f_i(x)leq b_i i=1,...,m. $$

如果你會(huì)python的話,就可以無(wú)障礙閱讀接下來(lái)的內(nèi)容,如果你不會(huì)python的話,花半天時(shí)間學(xué)一下再來(lái)！

當(dāng)然,使用docplex 的首先就要下載docplex,可以直接pip下載.

$ pip install docplex 

同時(shí)需要去下載一個(gè)cplex community edition　ILOG CPLEX ,
可以點(diǎn)擊try free edition,新建個(gè)賬號(hào)后下載一個(gè)cplex community edition.

在安裝完成后,在寫(xiě)一個(gè)python項(xiàng)目求解運(yùn)籌問(wèn)題之前呢,還要多做一點(diǎn)微小的工作.
對(duì)于cplex 的cp(Constraint Programming Modeling)模塊,可以在py文件中添加

from docplex.cp.config import context
context.solver.agent = "local"
context.solver.local.execfile = "/media/senmu/source/program_exp/ibm/ILOG/CPLEX_Studio_Community128/cpoptimizer/bin/x86-64_linux/cpoptimizer"

將context.solver.local.execfile 修改成你本地的目錄地址.

對(duì)于cplex 的mp(Mathematical Programming Modeling)模塊,可以參考docplex mp 設(shè)置

設(shè)置好PYTHONPATH,比如linux在~/.bashrc中添加

export PYTHONPATH="/media/senmu/source/program_exp/ibm/ILOG/CPLEX_Studio_Community128/cplex/python/3.6/x86-64_linux"

首先是一個(gè)經(jīng)典的八皇后問(wèn)題 Eight_queens_puzzle
解決八皇后問(wèn)題通常要用到遞歸,使用大量的計(jì)算資源,將其轉(zhuǎn)為約束問(wèn)題只需要添加all_diff約束
all_diff reference.

import docplex.cp

from docplex.cp.model import CpoModel
from sys import stdout

from docplex.cp.config import context
context.solver.agent = "local"
context.solver.local.execfile = "/media/senmu/source/program_exp/ibm/ILOG/CPLEX_Studio_Community128/cpoptimizer/bin/x86-64_linux/cpoptimizer"

NB_QUEEN = 8

mdl = CpoModel(name="NQueen")

x = mdl.integer_var_list(NB_QUEEN, 0, NB_QUEEN - 1, "X")

mdl.add(mdl.all_diff(x))

mdl.add(mdl.all_diff(x[i] + i for i in range(NB_QUEEN)))

mdl.add(mdl.all_diff(x[i] - i for i in range(NB_QUEEN)))

print("Solving model....")
msol = mdl.solve(TimeLimit=10)

if msol:
    stdout.write("Solution:")
    sol = [msol[v] for v in x]
    for v in range(NB_QUEEN):
        stdout.write(" " + str(sol[v]))
    stdout.write("
")
    stdout.write("Solve time: " + str(msol.get_solve_time()) + "
")
else:
    stdout.write("No solution found
")

可以直接訪問(wèn)github docplex-examples 查看更多例子，也可以使用nbviewer查看. 在nbviewer上查看docplex