Yes, I also couldn't build/find a small one which is abstract enough

If you'll find the time (file is added), I tried to simplify it as far as I can, I assume I also put more variables into module then needed and tried to exclude other possible errors, so here it is: (If you're interested, it is a CA guessing the exit time for a single (I simplified it) pedestrian and now I want to guess my parameters when knowing the exit time)

function[mmm_, nnn_] := (
  Module[
   {pex, dt, widths, w, l, LL, pot, tot},
   pex = 1;
   widths = 4;
   laenge = 32;
   TT = 10000;

   (* GRID 0.3 *)
   w = Table[0.3 i, {i, -widths/2, widths/2, 1}];(* 
   korrigieren*)
   l = Table[0.3 i + 0.15, {i, laenge - 1, 0, -1}];(* 
   23 wird zu 31 geändert wegen höherer DICHTE*)
   points = Table[
     {w[[i]], l[[j]]}, {j, 1, Length[l]}, {i, 1, Length[w]}];
   (*Potential*)
   pot = ConstantArray[0, {laenge, widths + 1}];
   LL = ConstantArray[0, {laenge, widths + 1}]; (*SUBmatrixeinträge*)

      Do[
    LL[[i, j]] = 
     Table[{i + kk, j + ll}, {kk, -1, 1}, {ll, -1, 1, 1}];(* 
    nachbarkoordinaten*)
    pot[[i, j]] = Table[
      points[[i, j]] + {0.3 kk, 0.3 ll},
      {ll, 1, -1, -1}, {kk, -1, 1}
      ];
    Do[
     {pot[[i, j, ll, 
        kk]]} = {Exp[-mmm*(Norm[pot[[i, j, ll, kk]]] - 
           Norm[points[[i, j]]])]},
     {ll, 1, 3}, {kk, 1, 3}];
    (* MITTELFELD MERKEN*)
    pot[[i, j, 2, 2]] = X;
    (* alle Ränder weg*)
    If[
     j == 1,(*links*)
     pot[[i, j]] = Drop[pot[[i, j]], 0, 1];
     LL[[i, j]] = Drop[LL[[i, j]], 0, 1];
     ];
    (*Print[pot[[i,j]], "nach links"];*)
    If[
     j == Length[w],(*rechts*)

     pot[[i, j]] = Drop[pot[[i, j]], 0, -1];
     LL[[i, j]] = Drop[LL[[i, j]], 0, -1];
     ];
    (*Print[pot[[i,j]], "nach rechts"];*)
    If[
     i == 1,(*oben*)
     pot[[i, j]] = Drop[pot[[i, j]], 1];
     LL[[i, j]] = Drop[LL[[i, j]], 1];
     ];
    (*Print[pot[[i,j]], "nach oben"];*)
    If[
     i == Length[l],(*unten*)
     pot[[i, j]] = Drop[pot[[i, j]], -1];
     LL[[i, j]] = Drop[LL[[i, j]], -1];
     ];
    (* //alle Ränder weg*)
    (*normalisieren*)

    tot = Total[Total[pot[[i, j]]]] - X;
    {{kk, ll}} = Position[pot[[i, j]], X];
    pot[[i, j]] = pot[[i, j]]/tot;
    pot[[i, j, kk, ll]] = 1 - nnn; (*KORREKTUR MOTIVATION*)

    tot = Total[Total[pot[[i, j]]]];
    pot[[i, j]] = pot[[i, j]]/tot;
    (*//normalisieren*)
    ,
    {i, 1, laenge}, {j, 1, widths + 1}];
   (* fertig Potentialfeld*)

   (* INITIAL CONDITION*)

   initial = 
    Transpose[{RandomInteger[{1, Length[l] - 1}, n + 30], 
      RandomInteger[{1, Length[w]}, n + 30]}];
   initial = DeleteDuplicates[initial];
   Length[initial] < n;
   While[Length[initial] < n,
    initial = 
     Transpose[{RandomInteger[{1, Length[l] - 1}, n + 30], 
       RandomInteger[{1, Length[w]}, n + 30]}];
    initial = DeleteDuplicates[initial]];
   Length[initial];
   initial = initial[[1 ;; n]];
   Length[initial];
   initial = {{1, 3}};
   (* // INITIAL CONDITION *)


   history = ConstantArray[0, {TT + 1, Length[l], Length[w]}];
   helpA = SparseArray[initial -> 1, {Length[l], Length[w]}];
   history[[1]] = history[[1]] + helpA;
   dataset = ConstantArray[0, TT + 1];
   wishes = ConstantArray[0, Length[initial]];
   dataset[[1]] = initial;

   For[tt = 1, tt <= TT, tt++,
    pointies = dataset[[tt]];
    For[ii = 1, ii <= Length[initial], ii++,
     i = pointies[[ii, 1]];
     j = pointies[[ii, 2]];
     If[i > 0 && j > 0,
      possibilities = 
       Flatten[LL[[i, j]], 1]; (*MÖGLICHKEITEN in der Matrix*)

      props = Flatten[
        pot[[i, j]]];(*Dazugehörige Wahrscheinlichkeiten*)

      nums = Table[jj, {jj, 1, Length[possibilities]}]; (* 
      Hilfsliste *)

      help1 = Table[ (* EXCLUDE wo Agenten sitzen, setze props auf 0 *)

                If[possibilities[[jj]] != {i, j},
         If[
          MemberQ[dataset[[tt]], possibilities[[jj]]],
          0,
          props[[jj]]],
         props[[jj]]],
        {jj, 1, Length[possibilities]}
        ]; 
      ind = 
       RandomChoice[help1 -> Table[nn, {nn, 1, Length[help1], 1}]];
      wishes[[ii]] = {possibilities[[ind]], {i, j}, help1[[ind]]};
      (* EXIT START UNGERADE*)
      If[
       {i, j} == {Length[l], Floor[Length[w]/2] + 1},
       (*Print["YES"];*)
       help3 = {
         {(1 - nnn)/(2 - nnn), 1/(2 - nnn)},
         {1, 2},
         {{Length[l], Floor[Length[w]/2] + 1}, {0, 
           0}}(*stehen raus*)
         };
       ind = RandomChoice[help3[[1]] -> help3[[2]]];
       wishes[[ii]] = {help3[[3, ind]], {i, j}, help3[[1, ind]]};
       ];
      If[
       {i, j} == {Length[l], Floor[Length[w]/2] + 2},
       (*Print["YES"];*)
       help3 = {
         {0.34*
           If[MemberQ[
             dataset[[tt]], {Length[l], Floor[Length[w]/2] + 1}], 0, 
            1], 0.66},(* so ist das nun ohne skip*)
         {1, 2},
         {{Length[l], Floor[Length[w]/2] + 1}, {0, 0}}(*mitte, 
         raus*)
         };
       ind = RandomChoice[help3[[1]] -> help3[[2]]];
       wishes[[ii]] = {help3[[3, ind]], {i, j}, help3[[1, ind]]};
       ];
      If[
       {i, j} == {Length[l], Floor[Length[w]/2]},
       (*Print["YES"];*)
       help3 = {
         {0.34*
           If[MemberQ[
             dataset[[tt]], {Length[l], Floor[Length[w]/2] + 1}], 0, 
            1], 0.66},(* so ist das nun ohne skip*)
         (*{(1-
         mm)/(2-mm),0.34/(2-mm),0.66/(2-mm)},*)(* 
         so war das früher*)
         {1, 2},
         {{Length[l], Floor[Length[w]/2] + 1}, {0, 0}}(* mitte, 
         raus*)
         };
       ind = RandomChoice[help3[[1]] -> help3[[2]]];
       wishes[[ii]] = {help3[[3, ind]], {i, j}, help3[[1, ind]]};
       (* 
       EXIT ENDE *)
       (*ELSE falls Punkt bereits draußen auf (0,
       0)*)
       ];
      ,(* KOMMA WICHTIG DA IF AUS*)

      wishes[[ii]] = {{0, 1}, {0, 0}, 1}
      ];
     ];
    dataset[[tt + 1]] = 
     wishes[[All, 1]];(*zukunft mit konflikten*)
    (* KONFLIKT*)

     counting = Tally[wishes[[All, 1]]];
    (*COUNTING Länge der *)
    For[
     iii = 1, iii <= Length[counting], iii++,
     If[Total[counting[[iii, 1]]] != 1,
      Do[
       If[counting[[iii, 2]] == MM,
        help3 = 
         Position[wishes[[All, 1]], counting[[iii, 1]]] // Flatten; (* 
        wo stehen die streitenden?*)
        For[
         jj = 1, jj <= Length[help3], jj++,
         dataset[[tt + 1, help3[[jj]] ]] = 
           dataset[[tt, help3[[jj]]]];
          ];
        winner = 
         RandomChoice[
          Table[wishes[[help3[[nn]], 3]], {nn, 1, MM}] -> help3];
        (*Print[winner];
        Print[dataset[[tt+1]]];*)

        dataset[[tt + 1, winner]] = counting[[iii, 1]]
        (*Print[dataset[[tt+1]]];*)
        ],
       {MM, 2, Max[counting[[;; , 2]]]}](* DO ENDE*)
      ]
     ];
    (* //KONFLIKT*)
    (* DURCHFLUSS AM AUSGANG*)

    If[MemberQ[dataset[[tt + 1]], {0, 0}],
     {{huepfer}} = Position[dataset[[tt + 1]], {0, 0}];
     dataset[[tt + 1, huepfer]] = 
      RandomChoice[{pex, 1 - pex} -> {{0, 0}, dataset[[tt, huepfer]]}];
     ];
    (* // DURCHFLUSS AM AUSGANG*)
    (* IST ES LEER? *)
    If[
     Total[Total[dataset[[tt]]]] == n,
     Break[]
     ]
    (* //IST ES LEER? *)
    ];
   Return[tt - 1]
   ]
  )

Then

function[1, 0]
function[3, 1]
function[10, 1]

works just fine, BUT

NMinimize[
 {(function[x, 0] - 70)^2, 3 < x < 5}, {x, 3, 5}]

shows me as an error, that my mmm_ or here x is not used in the calculation. So I assume somewhere I defined my variables terribly wrong

All the best

Attachments:

thx_for_the_help.nb

First of all, thank you alot.

Could you upload that file? And I know the issue with the Randomness but I assumed if I do it mutliple times there, it is a start (I had no better idea at the moment)

Dear Daniel, thanks again for the quick reply Just to understand it correctly,

function[x_?NumericQ, y_?NumericQ, z_?NumericQ] := ...

And then, when guessing e.g. x, I use

NMinimize[{(function[x, 1,2] -70)^2, 3 < x < 4}, {x, 3, 4}] ? Because this doesn't work. However, before going into detail, as written in the Link, the solution

NMinimize[{Hold[(function[x,1,2] - 70)^2, 3 < x < 4}, {x, 3, 4}]
NMinimize[{Hold[(function[x,1,2 ] - 70)^2, 3 < x < 4}, {x, 3, 4}]

gives me twice the same result, even my simulation has (more then one) propabilistic effect in it. I assume hold is the reason? But again, no idea why

I'll now try to build a minimal example to represent my problem

I don't understand the solution but somehow this is the answer https://eternaldisturbanceincosmos.wordpress.com/2011/04/27/nminimize-in-mathematica-could-drive-you-insane/