SOLVED. Help with lpSolver

[magleft]

Hello.
In my application I need to find the optimal solution to a combination of conditions.
To achieve this I tried to use the example for delphi - free pascal found at https://lpsolve.sourceforge.net/5.5/ .
as shown in the code. However it does not create the correct file.
Assigns the ret variable the value of the number of columns.
Even if I omit checking the ret variable, it doesn't create the correct file and the app crashes.
The file created is as follows:


*<meta creator='lp_solve v5.5'>
*<meta rows=1>
*<meta columns=15>
*<meta equalities=0>
*<meta integers=0>
*<meta origsense='MIN'>
*
NAME
ROWS
  N R0
  L R1
COLUMNS
RHS
     RHS R1 27.000000000
ENDATA

Where is the error? Any help is welcome

Code: Pascal  [Select][+][-]

1. procedure TFLipansi.SolveProblem ;
2. const
3.   TbFields:Array [0..11] of string = (
4.   'n','p','k','Mg','Cu','Zn','Mn','Fe','B','C','Ca','S' );
5. var
6.   Ncol:Integer ;
7.   j, ret, i: integer;
8.   colno: PIntArray ;
9.   row: PFloatArray ;
10.   lp: THandle;
11.  begin
12.   ret := 0;
13.   colno := nil;
14.   row := nil;
15.   (* We will build the model row by row
16.      So we start with creating a model with 0 rows and 2 columns *)
17.   Ncol := TbSolver.RecordCount ; (* there are two variables in the model *)
18.   lp := make_lp(0, Ncol);
19.   if (lp = 0) then
20.     ret := 1; (* couldn't construct a new model... *)
21.   (* let us name our variables. Not required, but can be usefull for debugging *)
22.   TbSolver.First ;
23.   while not(TbSolver.EOF) do
24.   begin
25.        set_col_name(lp,TbSolver.RecNo,PCHAR('C'+INTTOSTR(TbSolver.RecNo)))    ;  //pchar(TbSolver.FieldByName('NAME').AsString)
26.        TbSolver.Next ;
27.   end;
28.   if (ret = 0) then
29.   begin
30.     (* create space large enough for one row *)
31.     GetMem(colno, SizeOf(integer) * Ncol);
32.     GetMem(row, SizeOf(double) * Ncol);
33.     if ((colno = nil) or (row = nil)) then
34.       ret := 2;
35.   end;
36.   if (ret = 0) then
37.   begin
38.     set_add_rowmode(lp, true);  (* makes building the model faster if it is done rows by row *)
39.     for i:=0 to 11 do
40.     Begin
41.          if  strToFloat(StringGrid1.Cells[3,i])>0 then
42.          Begin
43.                j:=0;
44.                s:='';
45.                TbSolver.First ;
46.                while not(TbSolver.eof) do
47.                begin
48.                     colno^[j] := j;
49.                     row^[j] :=TbSolver.FieldByName(TbFields[i]).AsFloat  ;
50.                     TbSolver.Next ;
51.                     j:=j+1;
52.                end;
53.                if (not add_constraintex(lp, j, @row, @Ncol , 1, strToFloat(StringGrid1.Cells[3,i]))) then  
54.                  ret := 3;
55.          end;
56.     end;
57.   end;
58.  
59.   if (ret = 0) then
60.   begin
61.      set_add_rowmode(lp, false); (* rowmode should be turned off again when done building the model *)
62.      j:=0;
63.      TbSolver.First ;
64.      while not(TbSolver.eof) do
65.      begin
66.              colno^[j] := J;
67.              row^[j] := TbSolver.FieldByName('Price').AsFloat;
68.              TbSolver.Next ;
69.              j:=j+1;
70.         end;
71.        (* set the objective in lp_solve *)
72.         if (not set_obj_fnex(lp, j, @row, @Ncol )) then  ;
73. //          ret := 4;
74.       end;
75.  
76.       if (ret = 0) then
77.       begin
78.         (* set the object direction to maximize *)
79.         set_minim(lp);
80.  
81.         (* just out of curioucity, now show the model in lp format *)
82.       write_mps (lp, 'Solution.mps');
83.      end;
84.   end;
85.  
86.  

[TRon]

How are we suppose to help you ?

Code: [Select]

fpc -B test.pas
Free Pascal Compiler version 3.2.2 [2021/05/16] for x86_64
Copyright (c) 1993-2021 by Florian Klaempfl and others
Target OS: Linux for x86-64
Compiling test.pas
Compiling lpsolve.pas
test.pas(24,11) Error: Identifier not found "TbSolver"
test.pas(29,3) Error: Identifier not found "TbSolver"
test.pas(30,13) Error: Identifier not found "TbSolver"
test.pas(32,24) Error: Identifier not found "TbSolver"
test.pas(32,58) Error: Identifier not found "TbSolver"
test.pas(33,8) Error: Identifier not found "TbSolver"
test.pas(48,25) Error: Identifier not found "StringGrid1"
test.pas(51,16) Error: Identifier not found "s"
test.pas(52,16) Error: Identifier not found "TbSolver"
test.pas(53,26) Error: Identifier not found "TbSolver"
test.pas(56,31) Error: Identifier not found "TbSolver"
test.pas(57,21) Error: Identifier not found "TbSolver"
test.pas(60,76) Error: Identifier not found "StringGrid1"
test.pas(70,6) Error: Identifier not found "TbSolver"
test.pas(71,16) Error: Identifier not found "TbSolver"
test.pas(74,25) Error: Identifier not found "TbSolver"
test.pas(75,14) Error: Identifier not found "TbSolver"
test.pas(98,4) Fatal: There were 17 errors compiling module, stopping
Fatal: Compilation aborted
Error: /home/apps/fpc/3.2.2/bin/x86_64-linux/ppcx64 returned an error exitcode
And that is after wasting time getting things setup and create a test project.

[magleft]

I am attaching the program.
I managed to create lpx file.
How could I run the solver inside lazarus and get the results.

[TRon]

So, you have attached some random units that I have to construct into a project that I needed to create manually.

Then download yet another archive, namely the lpSolver IDE in order to obtain the missing classes. Those I can't install because they are not packages but merely some units. So that requires me to write a package for those components in order to be able to install them into Lazarus so that the project can finally be loaded.

Unless I am missing something obvious, "No, thank you ma'am".

[magleft]

I use str_add_constraint function and all is ok.
Thanks all for help.