# \[AMPL 24769\] How to read .sol files

**URL:** <https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719>\
**Category:** Google Group Mirror\
**Created:** [September 8, 2023, 12:10am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719 "2023-09-08T00:10:43Z")\
**Posts on this page:** 18\
**Page:** 1

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 8, 2023, 12:10am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/1 "2023-09-08T00:10:43Z")

</div>

Hi,  
I used ampl.setOption(‘cplex\_options’,‘poolstub savesol’)to generate feasible solution, but I do not know how to open this files and see the generated solutions

Could you please help? Thanks

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 8, 2023, 3:47pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/2 "2023-09-08T15:47:32Z")

</div>

CPLEX organizes the solutions as follows:

- The solution files are savesol1.sol, savesol2.sol, . . .
- The number of solution files saved is .npool – where is replaced by the name of your model’s objective function.  
To read a solution, use a command of the form

`solution savesol<n>.sol`

where is replaced by the solution number – for example, “solution savesol2.sol;” to read the second solution file. Here is an example of a loop that reads through all of the solutions:

```auto
for {k in 1..Total_Cost.npool} {
   solution ("savesol" & k & ".sol");
   display Trans;
};

```

(Replace Total\_Cost by the name of your objective, and “display Trans;” by the commands you want to use to view or process each solution.)

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 9, 2023, 11:08pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/3 "2023-09-09T23:08:37Z")

</div>

Thanks a lot, it works well in AMPL. Is there a link to show how to do that in python as I am using amplpy?

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 10, 2023, 6:15pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/4 "2023-09-10T18:15:21Z")

</div>

Using amplpy, you can do that as follows:

from amplpy import AMPL  
ampl = AMPL()  
ampl.eval(  
r"“”  
set I := 1…1000000;  
var x{I} integer \>= 0 \<= 1;  
param v{i in I} := 10 + Irand224() mod 200;  
param w{i in I} := v[i] + Irand224() mod 200;  
maximize profit: sum{i in I} v[i] \* x[i];  
s.t. capacity: sum{i in I} x[i] \<= 200;  
“”"  
)  
ampl.option[“solver”] = “cplex”  
ampl.option[“cplex\_options”] = “poolstub savesol”  
ampl.solve()  
for i in range(1, ampl.get\_value(“profit.npool”) + 1):  
ampl.eval(f"solution savesol{i}.sol;“) # load the solution  
print(i, ampl.get\_data(r”{i in I: x[i] \> 0} x[i]").to\_dict()) # display the non-zero variables

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 12, 2023, 5:29am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/5 "2023-09-12T05:29:05Z")

</div>

Thanks a lot for your reply. I changed the name of the objective function from profit to cost, I tried the following :

for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
ampl.eval(f"solution savesol{i}.sol;“)  
print(i, ampl.get\_data(r"x”).to\_dict())

But it gives me this error  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py”, line 53, in main  
for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Users\enhan\AppData\Local\Programs\Python\Python311\Lib\site-packages\amplpy\ampl.py”, line 437, in get\_value  
return self.\_impl.getValue(scalar\_expression)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
RuntimeError: file -  
line 1 offset 33  
Bad suffix .npool for cost

Any idea about resolving this error? thanks

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 12, 2023, 7:37am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/6 "2023-09-12T07:37:44Z")

</div>

Did you set CPLEX options with ampl.option[“cplex\_options”] = “poolstub savesol”? Please send us the output from cplex, it should indicate that it exported that suffix if poolstub was set.

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 14, 2023, 2:37am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/7 "2023-09-14T02:37:43Z")

</div>

Here is my script in python

def main(argc, argv):  
#os.chdir(os.path.dirname( **file** ) or os.curdir)

ampl.set\_option(“solver”, “cplex”)  
ampl.setOption(‘cplex\_options’,‘poolstub savesol’)

if argc \> 1:  
ampl.set\_option(“solver”, argv[1])

ampl.read(“C:/bin/lin\_strategies.mod”)  
ampl.read\_data(“C:/bin/strategies\_1.txt”)

ampl.solve()

for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
ampl.eval(f"solution savesol{i}.sol;“) # load the solution  
data\_x = ampl.get\_data(r"x”).to\_dict() # store the value of variable x  
print(data\_x)

if **name** == “ **main** ”:  
try:  
main(len(sys.argv), sys.argv)  
except Exception as e:  
print(e)  
raise

Now it gives me this output. It doesn’t print data\_x

CPLEX 12.6.0.1: poolstub savesol  
CPLEX 12.6.0.1: optimal integer solution within mipgap or absmipgap; objective 43723.26731  
6645 MIP simplex iterations  
0 branch-and-bound nodes  
absmipgap = 3, relmipgap = 6.86134e-05  
Wrote 12 solutions in solution pool  
to files savesol1.sol … savesol12.sol.  
suffix npool OUT;

How to save x in a new variable, then print it?

Also, I want to do something similar using Gurobi because it is faster. I used the following to set the option: ampl.setOption(‘gurobi\_options’, ‘ams\_stub=allopt ams\_mode=2 ams\_epsabs=0.5’)  
and the following loop to access the solution pool

for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
ampl.eval(f"solution allopt{i}.sol;“) # load the solution  
data\_x = ampl.get\_data(r"x”).to\_dict() # store the value of variable x  
print(data\_x)

but it doesn’t work, and gives me this error

Gurobi 5.6.3: ams\_stub=allopt  
Gurobi 5.6.3: optimal solution; objective 43723.26731  
56105 simplex iterations  
plus 74 simplex iterations for intbasis  
absmipgap = 3, relmipgap = 6.86e-05  
Alternative MIP solution 1, objective = 44973.26731  
Alternative MIP solution 2, objective = 45571.76731  
Alternative MIP solution 3, objective = 49931.26731  
Alternative MIP solution 4, objective = 52515.26731  
4 alternative MIP solutions written to allopt1.sol  
allopt4.sol  
“option abs\_boundtol 2.220446049250313e-16;”  
or “option rel\_boundtol 2.220446049250313e-16;”  
will change deduced dual values.  
file -  
line 1 offset 33  
Bad suffix .npool for cost  
Traceback (most recent call last):  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\pydevconsole.py”, line 364, in runcode  
coro = func()  
^^^^^^  
File “”, line 1, in   
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_bundle\pydev\_umd.py”, line 198, in runfile  
pydev\_imports.execfile(filename, global\_vars, local\_vars) # execute the script  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_imps\_pydev\_execfile.py”, line 18, in execfile  
exec(compile(contents+“\n”, file, ‘exec’), glob, loc)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py”, line 109, in   
main(len(sys.argv), sys.argv)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py”, line 58, in main  
for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Users\enhan\AppData\Local\Programs\Python\Python311\Lib\site-packages\amplpy\ampl.py”, line 437, in get\_value  
return self.\_impl.getValue(scalar\_expression)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
RuntimeError: file -  
line 1 offset 33  
Bad suffix .npool for cost

Thanks a lot for your support

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 14, 2023, 8:32am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/8 "2023-09-14T08:32:01Z")

</div>

You have Gurobi 5.6.3 and CPLEX 12.6.0.1, which are extremely old versions of both solvers (release in 2014). By upgrading to the latest version, with Gurobi 10, you can do that as follows:

from amplpy import AMPL  
ampl = AMPL()  
ampl.eval(  
r"“”  
set I := 1…10000;  
var x{I} integer \>= 0 \<= 1;  
param v{i in I} := 10 + Irand224() mod 200;  
param w{i in I} := v[i] + Irand224() mod 200;  
maximize profit: sum{i in I} v[i] \* x[i];  
s.t. capacity: sum{i in I} x[i] \<= 200;  
“”"  
)  
ampl.option[“solver”] = “gurobi”  
ampl.option[“gurobi\_options”] = “solstub=savesol”  
ampl.solve()  
for i in range(1, ampl.get\_value(“profit.npool”) + 1):  
ampl.eval(f"solution savesol{i}.sol;“)  
print(  
ampl.get\_data(r”{i in 1…\_nvars: \_var[i] != 0} (\_varname[i], \_var[i])").to\_list(  
skip\_index=True  
),  
)

In the code example from the previous message I retrieved the values for variable x, but you need to adjust the code to the variable names in your models. In the code example above, it retrieves the values for all non-zero variables in a list of pairs (variable, value).

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 14, 2023, 7:18pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/9 "2023-09-14T19:18:06Z")

</div>

It works fine with the latest Cplex, but still I have the same problem with Groubi 10, please see below. Thanks

PyDev console: starting.  
Python 3.11.4 (tags/v3.11.4:d2340ef, Jun 7 2023, 05:45:37) [MSC v.1934 64 bit (AMD64)] on win32  
runfile(‘C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py’, wdir=‘C:\Users\enhan\PycharmProjects\strategiesHM’)  
Gurobi 10.0.2: sol:poolgapabs = 150  
Gurobi 10.0.2: optimal solution; objective 43723.26731  
6793 simplex iterations  
1 branching nodes  
absmipgap=3, relmipgap=6.86134e-05  
file -  
line 1 offset 33  
Bad suffix .npool for cost  
Traceback (most recent call last):  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\pydevconsole.py”, line 364, in runcode  
coro = func()  
^^^^^^  
File “”, line 1, in   
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_bundle\pydev\_umd.py”, line 198, in runfile  
pydev\_imports.execfile(filename, global\_vars, local\_vars) # execute the script  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_imps\_pydev\_execfile.py”, line 18, in execfile  
exec(compile(contents+“\n”, file, ‘exec’), glob, loc)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py”, line 109, in   
main(len(sys.argv), sys.argv)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\get\_AMPL\_solution.py”, line 58, in main  
for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Users\enhan\AppData\Local\Programs\Python\Python311\Lib\site-packages\amplpy\ampl.py”, line 437, in get\_value  
return self.\_impl.getValue(scalar\_expression)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
RuntimeError: file -  
line 1 offset 33  
Bad suffix .npool for cost

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 14, 2023, 9:03pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/10 "2023-09-14T21:03:04Z")

</div>

Could you please send us the line where you set Gurobi options?

It should be something like ampl.option[“gurobi\_options”] = “solstub=savesol” but the solver output only shows “sol:poolgapabs = 150”. You can combine the two options as follows:

…  
ampl.option[“gurobi\_options”] = “solstub=savesol sol:poolgapabs = 150”  
…

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 15, 2023, 1:17am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/11 "2023-09-15T01:17:21Z")

</div>

Thanks for the support, it works fine with Groubi. Now, using Cplex, if I set this option ampl.setOption(‘cplex\_options’, “mipsearch = 2”) to change the search method it gives an error. Please see below

import sys  
from amplpy import AMPL, Environment

ampl = AMPL(Environment(r’C:/bin’))

def main(argc, argv):  
#os.chdir(os.path.dirname( **file** ) or os.curdir)

ampl.set\_option(“solver”, “cplex”)  
ampl.setOption(‘cplex\_options’,‘poolstub savesol’)  
ampl.setOption(‘cplex\_options’, “mipsearch = 2”)

if argc \> 1:  
ampl.set\_option(“solver”, argv[1])

ampl.read(“C:/bin/lin\_strategies.mod”)  
ampl.read\_data(“C:/bin/strategies\_1.txt”)

ampl.solve()

for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
ampl.eval(f"solution savesol{i}.sol;“) # load the solution  
data\_x = ampl.get\_data(r"x”).to\_dict() # store the value of variable x  
print(data\_x)

if **name** == “ **main** ”:  
try:  
main(len(sys.argv), sys.argv)  
except Exception as e:  
print(e)  
raise

it gives this error

CPLEX 22.1.1.0: mipsearch = 2  
CPLEX 22.1.1.0: optimal integer solution within mipgap or absmipgap; objective 43723.26731  
498571 MIP simplex iterations  
4377 branch-and-bound nodes  
absmipgap = 4.25, relmipgap = 9.72023e-05  
file -  
line 1 offset 33  
Bad suffix .npool for cost  
Traceback (most recent call last):  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\pydevconsole.py”, line 364, in runcode  
coro = func()  
^^^^^^  
File “”, line 1, in   
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_bundle\pydev\_umd.py”, line 198, in runfile  
pydev\_imports.execfile(filename, global\_vars, local\_vars) # execute the script  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Program Files\JetBrains\PyCharm 2023.1\plugins\python\helpers\pydev\_pydev\_imps\_pydev\_execfile.py”, line 18, in execfile  
exec(compile(contents+“\n”, file, ‘exec’), glob, loc)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\try\_solver.py”, line 30, in   
main(len(sys.argv), sys.argv)  
File “C:\Users\enhan\PycharmProjects\strategiesHM\scripts\try\_solver.py”, line 23, in main  
for i in range(1, ampl.get\_value(“cost.npool”) + 1):  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File “C:\Users\enhan\AppData\Local\Programs\Python\Python311\Lib\site-packages\amplpy\ampl.py”, line 437, in get\_value  
return self.\_impl.getValue(scalar\_expression)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
RuntimeError: file -  
line 1 offset 33  
Bad suffix .npool for cost

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 15, 2023, 9:44am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/12 "2023-09-15T09:44:07Z")

</div>

When you set the same option multiple times only the last value is kept. For instance:

ampl.setOption(‘cplex\_options’,‘poolstub savesol’)  
ampl.setOption(‘cplex\_options’, “mipsearch = 2”)

is equivalent to just:

ampl.setOption(‘cplex\_options’, “mipsearch = 2”)

In order to set both options you need to set them as follows:

ampl.setOption(‘cplex\_options’,‘poolstub savesol mipsearch = 2’)

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 15, 2023, 9:25pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/13 "2023-09-15T21:25:20Z")

</div>

it works perfect now, thanks a lot.  
I have another issue, I set this option ampl.setOption(‘cplex\_options’,‘poolstub savesol mipsearch = 2 nodesel = 3’) , and solved the model 10 times using looping. The pool of the first iteration contains 28 solutions, but afterwards the pool of at any other iteration contains only two solutions. Is there a reason for that? I am trying to generate as much feasible solutions as passible

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 15, 2023, 10:30pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/14 "2023-09-15T22:30:39Z")

</div>

Also, how to add a new seed to this option ampl.setOption(‘cplex\_options’,‘poolstub savesol mipsearch = 2 nodesel = 3’)  
I tried this, but doesn’t work  
random\_num = round((random.uniform(0.0, 10000)),0)  
seed\_value = f’seed=random\_num’  
ampl.setOption(‘cplex\_options’,“poolstub savesol mipsearch = 2 nodesel = 3 seed\_value”)

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 16, 2023, 10:24am UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/15 "2023-09-16T10:24:25Z")

</div>

Regarding the number of solutions found, there are options like poolintensity that may help (see all options for CPLEX at [https://dev.ampl.com/solvers/cplex/options.html](https://dev.ampl.com/solvers/cplex/options.html)).

Regarding seed, you can do it as follows:

random\_num = round((random.uniform(0.0, 10000)),0)  
ampl.setOption('cplex\_options", f"poolstub savesol mipsearch = 2 nodesel = 3 seed={random\_num}")

---

<div class="post-metadata">

**Author:** ![Hany\_Osman](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@Hany\_Osman](https://discuss.ampl.com/u/Hany_Osman)\
**Post date:** [September 16, 2023, 4:41pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/16 "2023-09-16T16:41:45Z")

</div>

Thanks,  
I used this

random\_num = round((random.uniform(0, 10000)), 0)  
ampl.setOption(“cplex\_options”, f"poolstub savesol mipsearch = 2 nodesel = 3 seed={random\_num}")

still gives an error, I do not know where “.0” comes from

CPLEX 22.1.1.0: poolstub savesol  
mipsearch = 2  
nodesel = 3  
seed=4629  
Unknown keyword “.0”  
CPLEX 22.1.1.0: Error in $cplex\_options.  
file -  
line 1 offset 33  
Bad suffix .npool for cost

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 16, 2023, 5:04pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/17 "2023-09-16T17:04:51Z")

</div>

Even after rounding random\_num is still a float so there is still a “.0” in formated string . You can cast it it int or format the f-string with 0 decimal points as follows:

ampl.setOption(“cplex\_options”, f"poolstub savesol mipsearch = 2 nodesel = 3 seed={random\_num:.0}")

---

<div class="post-metadata">

**Author:** ![AMPL\_Google\_Group](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@AMPL\_Google\_Group](https://discuss.ampl.com/u/AMPL_Google_Group)\
**Post date:** [September 16, 2023, 5:14pm UTC](https://discuss.ampl.com/t/ampl-24769-how-to-read-sol-files/719/18 "2023-09-16T17:14:09Z")

</div>

Sorry, missed the f in the previous reply:

ampl.setOption(“cplex\_options”, f"poolstub savesol mipsearch = 2 nodesel = 3 seed={random\_num:.0f}")