我正在尝试使用 amplpy 将 python 脚本链接到 ampl 模型，真正的愿望是使用脚本生成一些参数，并使用 ampl 找到某些变量的最佳值。
值得一提的是，该模型单独运行良好，没有错误，并找到了最优解。
由于我需要在 python 脚本中加载模型和参数，因此我尝试使用 amplpy.read() 和 amplpy.read_data() 导入 .dat 文件，但它不起作用。 python解释器返回的错误消息：
ampl.read('fpo-dt.dat')
Error:
po-dt.dat
line 2 offset 55
no data for set L
Traceback (most recent call last):
File "C:\Users\LaPSEE\AppData\Local\Temp\ipykernel_6064\4255500489.py", line 1, in <cell line: 1>
ampl.read('fpo-dt.dat')
File "C:\ProgramData\Miniconda3\lib\site-packages\amplpy\ampl.py", line 554, in read
self._error_handler_wrapper.check()
File "C:\ProgramData\Miniconda3\lib\site-packages\amplpy\ampl.py", line 704, in check
raise exp
File "C:\ProgramData\Miniconda3\lib\site-packages\amplpy\ampl.py", line 688, in error
self.error_handler.error(exception)
File "C:\ProgramData\Miniconda3\lib\site-packages\amplpy\errorhandler.py", line 25, in error
raise exception
AMPLException: po-dt.dat
line 2 offset 55
no data for set L
为了克服这个问题，我直接在脚本中定义参数。这就是我正在做的方式，对于与两个集合相关联的参数 GD。
from amplpy import AMPL, DataFrame
ampl = AMPL()
ampl.reset()
ampl.read('modelfpo.mod')
gd = ([[0, 0, 0],
[20.00, 20.00, 20.00],
[21.00, 24.00, 38.40],
[21.60, 27.00, 59.40],
[26.40, 33.00, 72.60],
[22.80, 28.50, 62.70],
[18.00, 18.00, 18.00],
[21.60, 27.00, 59.40],
[18.00, 22.50, 49.50],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[5.25, 6.00, 9.60],
[26.25, 33.60, 80.64],
[23.10, 27.30, 49.14],
[27.50, 35.20, 84.48],
[21.00, 24.00, 38.40],
[26.40, 33.00, 72.60],
[20.00, 22.00, 30.80],
[24.15, 29.40, 58.80],
[18.00, 19.80, 27.72],
[21.00, 22.05, 26.46],
[25.00, 32.00, 76.80],
[22.00, 26.00, 46.80],
[18.00, 19.80, 27.72],
[10.35, 12.60, 25.20],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[6.60, 7.80, 14.04]])
df_gd = DataFrame('GD', data=gd)
ampl.set_data(df_gd,'GD')
翻译员由此返回：
ampl.set_data(df_gd,'GD')
Traceback (most recent call last):
File "C:\Users\xxxx\AppData\Local\Temp\ipykernel_6064\2016685981.py", line 1, in <cell line: 1>
ampl.set_data(df_gd,'GD')
File "C:\ProgramData\Miniconda3\lib\site-packages\amplpy\ampl.py", line 608, in set_data
self._impl.setData(data._impl, set_name)
RuntimeError: file -
line 1 offset 10
GD is not a set
当您尝试加载索引参数的数据而不为索引集提供数据时，通常会出现错误消息
no data for set Lset L;
param p{L};
data;
param p :=
1 23
2 32
4 12;
model;
display p;
会产生错误：
Error executing "display" command:
error processing param p[...]:
no data for set L
在数据声明中，如果您想与参数同时加载索引集，您可以提供索引集的名称：
set L;
param p{L};
data;
param : L : p :=
1 23
2 32
4 12;
model;
关于错误消息
GD is not a setampl.set_datafrom amplpy import AMPL
import pandas as pd
ampl = AMPL()
ampl.reset()
ampl.eval("""
set I;
set J;
param GD{I,J};
""")
gd = [[0, 0, 0],
[20.00, 20.00, 20.00],
[21.00, 24.00, 38.40],
[21.60, 27.00, 59.40],
[26.40, 33.00, 72.60],
[22.80, 28.50, 62.70],
[18.00, 18.00, 18.00],
[21.60, 27.00, 59.40],
[18.00, 22.50, 49.50],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[5.25, 6.00, 9.60],
[26.25, 33.60, 80.64],
[23.10, 27.30, 49.14],
[27.50, 35.20, 84.48],
[21.00, 24.00, 38.40],
[26.40, 33.00, 72.60],
[20.00, 22.00, 30.80],
[24.15, 29.40, 58.80],
[18.00, 19.80, 27.72],
[21.00, 22.05, 26.46],
[25.00, 32.00, 76.80],
[22.00, 26.00, 46.80],
[18.00, 19.80, 27.72],
[10.35, 12.60, 25.20],
[0.00, 0.00, 0.00],
[0.00, 0.00, 0.00],
[6.60, 7.80, 14.04]]
df_gd = pd.DataFrame(columns=["I", "J", "GD"], data=gd)
ampl.set["I"] = set(df_gd["I"].tolist()) # load data for set I
ampl.set["J"] = set(df_gd["J"].tolist()) # load data for set J
ampl.param["GD"] = df_gd.set_index(["I", "J"]) # load data for paramater GD
ampl.eval("display GD;")