program XTestALGLIB;
{$IFDEF FPC}
{$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
    SysUtils, Classes, Math, XALGLIB;

procedure function_cx_1_func(const c: TVector; const x: TVector; var func: Double; obj: Pointer);
begin
    func := c[0]/(power((1.0+c[1]*exp(-c[2]*x[0])),(1.0/c[3])))
end;

var
    x: TMatrix;
    y: TVector;
    c: TVector;
    epsx: Double;
    maxits: TALGLIBInteger;
    info: TALGLIBInteger;
    state: Tlsfitstate;
    rep: Tlsfitreport;
    diffstep: Double;
    w: TVector;

begin
    state:=nil;

    x:=Str2Matrix('[[1], [2], [3], [4], [5], [6], [7], [8], [9], [10],   [11], [12], [13], [14],   [15], [16], [17], [18],   [19], [20], [21], [22],   [23], [24], [25], [26], [27], [28], [29]]');
   
    setlength(y,29);
    y[0]:=276.6724171 ;
    y[1]:=294.7418196 ;
    y[2]:=312.999814 ;
    y[3]:=318.796855 ;
    y[4]:=327.9809221 ;
    y[5]:=348.5382184 ;
    y[6]:=373.6247255 ;
    y[7]:=390.9853543 ;
    y[8]:=   439.8460131;
    y[9]:=481.6166667 ;
    y[10]:=508.9197225 ;
    y[11]:=516.696677 ;
    y[12]:=502.5845254 ;
    y[13]:=504.3674456  ;
    y[14]:=539.8693852 ;
    y[15]:=568.5217391 ;
    y[16]:=612.2468205 ;
    y[17]:=   694.9141966 ;
    y[18]:=798.5451169 ;
    y[19]:=893.4315531 ;
    y[20]:=1004.368269 ;
    y[21]:=1152.037148 ;
    y[22]:=1274.113633 ;
    y[23]:=1401.486387 ;
    y[24]:=1578.892632 ;
    y[25]:=1776.018034 ;
    y[26]:=1972.037091 ;
    y[27]:=2205.325444 ;
    y[28]:=   2285.438293 ;
   
    c:=Str2Vector('[25080, 1841, 0.1523, 1.594]');
    epsx:=1E-6;
    maxits:=0;
    diffstep:=1E-6;

    // Fitting without weights

    lsfitcreatef(x, y, c, diffstep, state);
    lsfitsetcond(state, epsx, maxits);
    lsfitfit(state, function_cx_1_func, nil, nil);
    lsfitresults(state, info, c, rep);
    WriteLn(Format('%d', [info])); // EXPECTED: 2
    WriteLn(Format('%s', [FormatVector(c,1)])); // EXPECTED: [5884.4,19373,0.3088,3.3937]
   
    FreeAndNil(state);

    ReadLn;
    ExitCode:=0;
end.