lazarus-ccr/applications/lazstats/source/forms/analysis/descriptive/comparedistunit.pas

// Use file "cansas.laz" for testing

unit CompareDistUnit;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
  StdCtrls, Buttons, ExtCtrls, ComCtrls,
  FunctionsLib, Globals, GraphLib, DataProcs, MainDM, MainUnit,
  BasicStatsFormUnit, ReportFrameUnit, ChartFrameUnit;

type
  TCompareTo = (ctTheoreticalDistrib, ctVariable);
  TCompareDist = (cd_Normal, cd_t, cd_ChiSq, cd_F, cd_Poisson);

  { TCompareDistFrm }

  TCompareDistFrm = class(TBasicStatsForm)
    Bevel1: TBevel;
    DF1Edit: TEdit;
    DF2Edit: TEdit;
    DistGroup: TGroupBox;
    DF1Label: TLabel;
    DF2Label: TLabel;
    PageControl1: TPageControl;
    ParamsSplitter: TSplitter;
    NormalDistChk: TRadioButton;
    FreqChartPage: TTabSheet;
    tDistChk: TRadioButton;
    ChiSqDistChk: TRadioButton;
    FDistChk: TRadioButton;
    PoissonDistChk: TRadioButton;
    ReportPage: TTabSheet;
    CumFreqChartPage: TTabSheet;
    Notebook: TNotebook;
    BarPlotBtn: TSpeedButton;
    LinePlotBtn: TSpeedButton;
    TheoreticalDistPage: TPage;
    VariablePage: TPage;
    ParamsPanel: TPanel;
    BothChk: TCheckBox;
    OptionsGroup: TGroupBox;
    ResetBtn: TButton;
    ComputeBtn: TButton;
    CloseBtn: TButton;
    CompareGroup: TRadioGroup;
    VarOneEdit: TEdit;
    VarTwoEdit: TEdit;
    Label2: TLabel;
    Label3: TLabel;
    Var1InBtn: TBitBtn;
    Var1OutBtn: TBitBtn;
    Var2InBtn: TBitBtn;
    Var2OutBtn: TBitBtn;
    Label1: TLabel;
    VarList: TListBox;
    procedure CloseBtnClick(Sender: TObject);
    procedure CompareGroupClick(Sender: TObject);
    procedure ComputeBtnClick(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure DistChange(Sender: TObject);
    procedure ResetBtnClick(Sender: TObject);
    procedure Var1InBtnClick(Sender: TObject);
    procedure Var1OutBtnClick(Sender: TObject);
    procedure Var2InBtnClick(Sender: TObject);
    procedure Var2OutBtnClick(Sender: TObject);
    procedure VarListDblClick(Sender: TObject);
    procedure VarListSelectionChange(Sender: TObject; {%H-}User: boolean);

  private
    FReportFrame: TReportFrame;
    FCumFreqChartFrame: TChartFrame;
    FFreqChartFrame: TChartFrame;
    FAutoSized: Boolean;
    CompareTo: TCompareTo;
    CompareDist: TCompareDist;
    procedure CalcFreq(XValues, FreqValues, CumFreqValues: DblDyneVec;
      AMin, AMax: Double; ANumIntervals, ANumCases: Integer; DF1: Integer = -1;
      DF2: Integer = -1);
    procedure CalcTheoreticalDist(XValues, FreqValues, CumFreqValues: DblDyneVec;
      ANumIntervals, ANumCases: Integer; out AName: String);
    procedure Plot(AChartFrame: TChartFrame; Y1Values, Y2Values: DblDyneVec;
      AName1, AName2: String);
    procedure UpdateBtnStates;
    procedure UpdateDF1;
    function Validate(ANumCases: Integer;
      out AMsg: String; out AControl: TWinControl): Boolean;

  public
    procedure Reset; override;
  end; 


var
  CompareDistFrm: TCompareDistFrm;


implementation

{$R *.lfm}

uses
  Math,
  TACustomSeries, TASeries,
  Utils, MathUnit;


{ TCompareDistFrm }

procedure TCompareDistFrm.CalcFreq(XValues, FreqValues, CumFreqValues: DblDyneVec;
  AMin, AMax: Double; ANumIntervals, ANumCases: Integer; DF1: Integer = -1;
  DF2: Integer = -1);
var
  dx: Double;
  i: Integer;

  procedure Calc(AProb1, AProb2: Double);
  begin
    FreqValues[i] := abs(AProb2 - AProb1) * ANumCases;
  end;

begin
  dx := (AMax - AMin) / ANumIntervals;
  for i := 0 to ANumIntervals do
    XValues[i] := AMin + i * dx;

  for i := 0 to ANumIntervals - 1 do
    case CompareDist of
      cd_Normal:
        Calc(NormalDist(XValues[i]), NormalDist(XValues[i+1]));
      cd_t:
        Calc(0.5 * ProbT(XValues[i], DF1), 0.5 * ProbT(XValues[i+1], DF1));
      cd_ChiSq:
        Calc(ChiSquaredProb(XValues[i], DF1), ChiSquaredProb(XValues[i+1], DF1));
      cd_F:
        Calc(ProbF(XValues[i], DF1, DF2), ProbF(XValues[i+1], DF1, DF2));
      cd_Poisson:
        Calc(PoissonCDF(round(XValues[i]), DF1), PoissonCDF(round(XValues[i+1]), DF1));
//        Calc(PoissonPDF(round(XValues[i]), DF1), 0);
    end;

  CumFreqValues[0] := FreqValues[0];
  for i := 1 to ANumIntervals - 1 do
    CumFreqValues[i] := CumFreqValues[i-1] + FreqValues[i];
end;


procedure TCompareDistFrm.CalcTheoreticalDist(XValues, FreqValues, CumFreqValues: DblDyneVec;
  ANumIntervals, ANumCases: Integer; out AName: String);
var
  min, max: Double;
  DF1: Integer = -1;
  DF2: Integer = -1;
  a: Double;
begin
  if TryStrToFloat(DF1Edit.Text, a) then
    DF1 := round(a);
  if TryStrToFloat(DF2Edit.Text, a) then
    DF2 := round(a);

  case CompareDist of
    cd_Normal:
      begin
        min := -3.0;
        max :=  3.0;
        AName := 'Normal dist';
      end;
    cd_t:
      begin
        min := -3.0;
        max :=  3.0;
        AName := 't dist';
      end;
    cd_ChiSq:
      begin
        min := 0.0;
        max := 20.0;
        AName := 'Chi-sq dist';
      end;
    cd_F:
      begin
        min := 0.0;
        max := 2.0;
        AName := 'F dist';
      end;
    cd_Poisson:
      ; // will be handled separately
  end;

  CalcFreq(XValues, FreqValues, CumFreqValues, min, max, ANumIntervals, ANumCases, DF1, DF2);
end;



(*
  if NormalDistChk.Checked then // normal distribution curve
  begin
    name2 := 'Normal';
    min2 := -3.0;
    max2 := 3.0;
    range2 := max2 - min2;
    incrsize2 := range2 / noints;
    Xvalue2[0] := min2;
    Xvalue2[noints] := max2;
    for i := 1 to noInts do
    begin
      Xvalue2[i-1] := min2 + (i-1) * incrSize2;
      Xvalue2[i] := min2 + (i) * incrSize2;
      prob1 := probz(abs(Xvalue2[i-1]));
      prob2 := probz(abs(Xvalue2[i]));
      if prob1 > prob2 then
        Var2Freq[i-1] := round((prob1 - prob2) * nCases)
      else
        Var2Freq[i-1] := round((prob2 - prob1) * nCases)
    end;
    Cumfreq2[0] := Var2Freq[0];
    for i := 1 to noints do
      Cumfreq2[i] := Cumfreq2[i-1] + Var2Freq[i];
  end
end;
*)

procedure TCompareDistFrm.CloseBtnClick(Sender: TObject);
begin
  Close;
end;


procedure TCompareDistFrm.CompareGroupClick(Sender: TObject);
begin
  CompareTo := TCompareTo(CompareGroup.ItemIndex);
  Notebook.PageIndex := CompareGroup.ItemIndex;
end;


procedure TCompareDistFrm.ComputeBtnClick(Sender: TObject);
var
  var1Freq: DblDyneVec = nil;  // could be IntDyneVec, but simpler charting this way
  var2Freq: DblDyneVec = nil;
  xValue1: DblDyneVec = nil;
  xValue2: DblDyneVec = nil;
  cumfreq1: DblDyneVec = nil;
  cumfreq2: DblDyneVec = nil;
  i, j, k, col1, col2, nCases, noInts: integer;
  min1, max1, min2, max2, range1, range2, value: double;
  incrSize1, incrSize2, {%H-}KS: double;
  cellVal, name1, name2: string;
  msg: String;
  C: TWinControl;
  lReport: TStrings;
begin
  SetLength(var1Freq, NoCases + 1);
  SetLength(var2Freq, NoCases + 1);
  SetLength(xValue1,  NoCases + 1);
  SetLength(xValue2,  NoCases + 1);
  SetLength(cumfreq1, NoCases + 1);
  SetLength(cumfreq2, NoCases + 1);

  // Get columns of the variables
  col1 := 0;
  for i := 1 to NoVariables do
    if VarOneEdit.Text = OS3MainFrm.DataGrid.Cells[i, 0] then col1 := i;

  col2 := 0;
  if CompareTo = ctVariable then
    for i := 1 to NoVariables do
      if VarTwoEdit.Text = OS3MainFrm.DataGrid.Cells[i, 0] then col2 := i;

  // Check existence of required variables
  msg := '';
  case CompareTo of
    ctTheoreticalDistrib:
      if col1 = 0 then
       msg := 'Variable not specified.';
    ctVariable:
      if col1 = 0 then
        msg := 'Variable One is not specified.'
      else if col2 = 0 then
        msg := 'Variable Two is not specified.';
  end;
  if msg <> '' then
  begin
    ErrorMsg(msg);
    exit;
  end;

  // Get min and max values for variable in col1, as well as true number of cases
  min1 := Infinity;
  max1 := -Infinity;
  nCases := 0;
  for j := 1 to NoCases do
  begin
    if not ValidValue(j, col1) then continue;
    value := StrToFloat(OS3MainFrm.DataGrid.Cells[col1, j]);
    if value > max1 then max1 := value;
    if value < min1 then min1 := value;
    inc(nCases);
  end;

  // Validate
  if not Validate(nCases, msg, C) then begin
    C.SetFocus;
    ErrorMsg(msg);
  end;

  // Get number of intervals
  noInts := NoCases - 1;      // wp: why NoCases here, and not nCases?
  if noInts > 20 then noints := 20;

  range1 := max1 - min1 + 1.0;
  incrSize1 := range1 / noInts;
  name1 := VarOneEdit.Text;

  // Repeat for variable 2 (if Compare To is selected as "Another variable")
  if CompareTo = ctVariable then
  begin
    min2 := Infinity;
    max2 := -Infinity;
    for j := 1 to NoCases do
    begin
      if not ValidValue(j, col2) then continue;
      value := StrToFloat(OS3MainFrm.DataGrid.Cells[col2, j]);
      if value > max2 then max2 := value;
      if value < min2 then min2 := value;
    end;
    range2 := max2 - min2 + 1.0;
    incrSize2 := range2 / noInts;
    name2 := VarTwoEdit.Text;
  end;

  // Get frequency of cases in each interval
  for j := 1 to noints+1 do
    var1Freq[j-1] := 0;

  for j := 1 to NoCases do
  begin
    if not ValidValue(j, col1) then continue;
    value := StrToFloat(OS3MainFrm.DataGrid.Cells[col1, j]);
    for k := 1 to noInts do
    begin
      if (value >= min1 + (k-1) * incrSize1) and (value < min1 + k * incrSize1) then
        var1Freq[k-1] := var1Freq[k-1] + 1;
    end;
  end;

  cumFreq1[0] := var1Freq[0];
  for j := 1 to noInts+1 do
    xValue1[j-1] := min1 + (j-1) * incrSize1;
  for j := 1 to noInts do
    cumFreq1[j] := cumFreq1[j-1] + var1Freq[j];

  // Repeat for 2nd variable, if required
  if CompareTo = ctVariable then
  begin
    for j := 1 to noInts+1 do
      var2Freq[j-1] := 0;

    for j := 1 to NoCases do
    begin
      if not ValidValue(j, col2) then continue;
      value := StrToFloat(OS3MainFrm.DataGrid.Cells[col2, j]);
      for k := 1 to noInts do
      begin
        if (value >= min2 + (k-1) * incrsize2) and (value < min2 + k * incrsize2) then
          var2Freq[k-1] := var2Freq[k-1] + 1;
      end;
    end;

    cumfreq2[0] := var2Freq[0];
    for j := 1 to noInts+1 do
      xValue2[j-1] := min2 + (j-1) * incrSize2;
    for j := 1 to noInts do
      cumFreq2[j] := cumFreq2[j-1] + var2Freq[j];
  end;

  // Get theoretical distribution frequencies for selected distribution, if required.
  if CompareDist = cd_Poisson then
  begin
    CalcFreq(xValue2, var2Freq, cumFreq2, min1, min2, noInts, nCases, StrToInt(DF1Edit.Text));
    name2 := 'Poisson';
  end
  else
    CalcTheoreticalDist(xValue2, var2Freq, cumFreq2, noInts, nCases, name2);

  (*


  if CompareTo = ctTheoreticalDistrib then
  begin
    if NormalDistChk.Checked then // normal distribution curve
    begin
      name2 := 'Normal';
      min2 := -3.0;
      max2 := 3.0;
      range2 := max2 - min2;
      incrsize2 := range2 / noints;
      Xvalue2[0] := min2;
      Xvalue2[noints] := max2;
      for i := 1 to noInts do
      begin
        Xvalue2[i-1] := min2 + (i-1) * incrSize2;
        Xvalue2[i] := min2 + (i) * incrSize2;
        prob1 := probz(abs(Xvalue2[i-1]));
        prob2 := probz(abs(Xvalue2[i]));
        if prob1 > prob2 then
          Var2Freq[i-1] := round((prob1 - prob2) * nCases)
        else
          Var2Freq[i-1] := round((prob2 - prob1) * nCases)
      end;
      Cumfreq2[0] := Var2Freq[0];
      for i := 1 to noints do
        Cumfreq2[i] := Cumfreq2[i-1] + Var2Freq[i];
    end
    else
    if tDistChk.Checked then // t-distribution
    begin
      name2 := 't-Dist.';
      min2 := -3.0;
      max2 := 3.0;
      df1 := nCases - 1;
      range2 := max2 - min2;
      incrsize2 := range2 / noints;
      Xvalue2[0] := min2;
      Xvalue2[noints] := max2;
      for i := 1 to noInts do
      begin
        Xvalue2[i-1] := min2 + (i-1) * incrSize2;
        Xvalue2[i] := min2 + (i) * incrSize2;
        prob1 := 0.5 * probt(Xvalue2[i-1],df1);
        prob2 := 0.5 * probt(Xvalue2[i],df1);
        if prob1 > prob2 then
          Var2Freq[i-1] := round((prob1-prob2) * nCases)
        else
          Var2Freq[i-1] := round((prob2-prob1) * nCases)
      end;
      Cumfreq2[0] := Var2Freq[0];
      for i := 1 to noInts do
        Cumfreq2[i] := Cumfreq2[i-1] + Var2Freq[i];
    end
    else
    if ChiSqDistChk.Checked then // chi squared distribution
    begin
      cellval := InputBox('Deg. Freedom 1 Entry','DF 1','');
      df1 := StrToInt(cellval);
      name2 := 'Chi Sq';
      min2 := 0.0;
      max2 := 20.0;
      range2 := max2 - min2;
      incrSize2 := range2 / noInts;
      xValue2[0] := min2;
      xValue2[noInts] := max2;
      for i := 1 to noints do
      begin
        Xvalue2[i-1] := min2 + (i-1) * incrSize2;
        Xvalue2[i] := min2 + (i) * incrSize2;
        prob1 := chisquaredprob(Xvalue2[i-1],df1);
        prob2 := chisquaredprob(Xvalue2[i],df1);
        if prob1 > prob2 then
          Var2Freq[i-1] := round((prob1-prob2) * nCases)
        else
          Var2Freq[i-1] := round((prob2-prob1) * nCases)
      end;
      cumfreq2[0] := var2Freq[0];
      for i := 1 to noints do
        cumfreq2[i] := cumfreq2[i-1] + var2Freq[i];
    end
    else
    if FDistChk.Checked then // F distribution
    begin
      // get degrees of freedom
      cellval := InputBox('Deg. Freedom 1 Entry','DF 1','');
      df1 := StrToInt(cellval);
      cellval := InputBox('Deg. Freedom 2 Entry','DF 2','');
      df2 := StrToInt(cellval);
      name2 := 'F Dist.';
      min2 := 0.0;
      max2 := 3.0;
      range2 := max2 - min2;
      incrsize2 := range2 / noints;
      Xvalue2[0] := min2;
      Xvalue2[noints] := max2;
      for i := 1 to noInts do
      begin
        Xvalue2[i-1] := min2 + (i-1) * incrSize2;
        Xvalue2[i] := min2 + (i) * incrSize2;
        prob1 := ProbF(Xvalue2[i-1],df1,df2);
        prob2 := ProbF(Xvalue2[i],df1,df2);
        if prob1 > prob2 then
          Var2Freq[i-1] := round((prob1-prob2) * nCases)
        else
          Var2Freq[i-1] := round((prob2-prob1) * nCases)
      end;
      cumfreq2[0] := Var2Freq[0];
      for i := 1 to noInts do
        cumfreq2[i] := cumfreq2[i-1] + var2Freq[i];
    end
    else
    if PoissonDistChk.Checked then // Poisson distribution
    begin
      name2 := 'Poisson';
      mean := 0; // use as parameter a in pdf call
      min2 := min1;
      max2 := max1;
      if max2 > 13 then
      begin
        ErrorMsg('Value > 13 found. Factorial too large - exiting.');
        exit;
      end;
      for i := 1 to nCases do
        mean := mean + StrToFloat(OS3MainFrm.DataGrid.Cells[col1, i]);
      mean := mean / nCases;
      cellval := IntToStr(round(mean));
      cellval := InputBox('Parameter Entry (mean)', 'DF 1', cellval);
      degfree := StrToFloat(cellval);
      range2 := max2 - min2;
      incrsize2 := range2 / noInts;
//             Xvalue2[0] := min2;
      Xvalue2[noints] := max2;
      for i := 1 to noints do
      begin
        Xvalue2[i-1] := min2 + (i-1) * incrSize2;
        Xvalue2[i] := min2 + (i) * incrSize2;
        poisson_pdf ( round(Xvalue2[i-1]), degfree, prob1 );
//                  prob1 := (Xvalue2[i-1],df1);
//                  prob2 := chisquaredprob(Xvalue2[i],df1);
//                  if prob1 > prob2 then
       Var2Freq[i-1] := round((prob1) * nCases);
//                  else Var2Freq[i-1] := round((prob2-prob1) * Ncases)
      end;
      cumfreq2[0] := var2Freq[0];
      for i := 1 to noInts do
        cumfreq2[i] := cumfreq2[i-1] + var2Freq[i];
    end;
  end;

  *)
  lReport := TStringList.Create;
  try
    lReport.Add('DISTRIBUTION COMPARISON by Bill Miller');
    lReport.Add('');
    lReport.Add('%10s   %10s   %10s   %10s   %10s   %10s', [
      name1, name1, name1, name2, name2, name2
    ]);
    lReport.Add('%10s   %10s   %10s   %10s   %10s   %10s', [
      'X1 Value', 'Frequency', 'Cum. Freq.', 'X2 Value', 'Frequency', 'Cum. Freq.'
    ]);
    lReport.Add('----------   ----------   ----------  ----------   ----------   ----------');
    for i := 1 to noints do
      lReport.Add('%10.3f   %10.0f   %10.3f   %10.3f   %10.0f   %10.3f', [
        XValue1[i-1], Var1Freq[i-1], Cumfreq1[i-1], XValue2[i-1], Var2Freq[i-1], Cumfreq2[i-1]
      ]);
    lReport.Add('');
    cellval := 'D';
    KS := KolmogorovTest(noInts, Cumfreq1, noInts, Cumfreq2, cellVal, lReport);
  // lReport.Add('Kolmogorov-Smirnov statistic := %5.3f', [KS]);

    FReportFrame.DisplayReport(lReport);
  finally
    lReport.Free;
  end;

  // plot the cdfs
  Plot(FCumFreqChartFrame, cumFreq1, cumFreq2, VarOneEdit.Text, name2);

  if BothChk.Checked then
    Plot(FFreqChartFrame, var1Freq, var2Freq, VarOneEdit.Text, name2);

  FreqChartPage.TabVisible := BothChk.Checked;

  (*



  xtitle := 'Red = ' + VarOneEdit.Text + ' Blue = ' + name2;
  cellval := 'Plot of Cumulative Distributions';
  {
  if LinesChk.Checked then
    GraphFrm.barwideprop := 1.0
  else
    GraphFrm.barwideprop := 0.5;
  }
  GraphFrm.nosets := 2;
  GraphFrm.nbars := noints+1;
  GraphFrm.Heading := cellval;
  GraphFrm.XTitle := xtitle;
  GraphFrm.YTitle := 'Frequency';
  SetLength(GraphFrm.Ypoints,2,noints+1);
  SetLength(GraphFrm.Xpoints,1,noints+1);
  for k := 1 to noints+1 do
  begin
    GraphFrm.Ypoints[0,k-1] := Cumfreq1[k-1];
    GraphFrm.Ypoints[1,k-1] := CumFreq2[k-1];
    GraphFrm.Xpoints[0,k-1] := k;
  end;
  GraphFrm.AutoScaled := true;
  {
  if LinesChk.Checked then
    GraphFrm.GraphType := 6 // 3d lines
  else
    GraphFrm.GraphType := 8;  // 3D points
    }
  GraphFrm.BackColor := clYellow;
  GraphFrm.WallColor := clBlue;
  GraphFrm.FloorColor := clGray;
  GraphFrm.ShowLeftWall := true;
  GraphFrm.ShowRightWall := true;
  GraphFrm.ShowBottomWall := true;
  GraphFrm.ShowBackWall := true;
  GraphFrm.ShowModal;
  GraphFrm.Xpoints := nil;
  GraphFrm.Ypoints := nil;

  if BothChk.Checked then // plot the frequencies
  begin
    xtitle := 'Red = ' + VarOneEdit.Text + ' Blue = ' + name2;
    cellval := 'Plot of Cumulative Distributions';
    {
    if LinesChk.Checked then
      GraphFrm.BarWideProp := 1.0
    else
      GraphFrm.BarWideProp := 0.5;
      }
    GraphFrm.nosets := 2;
    GraphFrm.nbars := noints+1;
    GraphFrm.Heading := cellval;
    GraphFrm.XTitle := xtitle;
    GraphFrm.YTitle := 'Frequency';
    SetLength(GraphFrm.Ypoints,2,noints+1);
    SetLength(GraphFrm.Xpoints,1,noints+1);
    for k := 1 to noints+1 do
    begin
      GraphFrm.Ypoints[0,k-1] := Var1Freq[k-1];
      GraphFrm.Ypoints[1,k-1] := Var2Freq[k-1];
      GraphFrm.Xpoints[0,k-1] := k;
    end;
    GraphFrm.AutoScaled := true;
    {
    if LinesChk.Checked then
      GraphFrm.GraphType := 6 // 3d lines
    else
      GraphFrm.GraphType := 8;  // 3D points
      }
    GraphFrm.BackColor := clYellow;
    GraphFrm.WallColor := clBlue;
    GraphFrm.FloorColor := clGray;
    GraphFrm.ShowLeftWall := true;
    GraphFrm.ShowRightWall := true;
    GraphFrm.ShowBottomWall := true;
    GraphFrm.ShowBackWall := true;
    GraphFrm.ShowModal;
    GraphFrm.Xpoints := nil;
    GraphFrm.Ypoints := nil;
  end;
    *)

  // clean up
  Cumfreq2 := nil;
  Cumfreq1 := nil;
  XValue1 := nil;
  XValue2 := nil;
  Var2Freq := nil;
  Var1Freq := nil;
end;


procedure TCompareDistFrm.DistChange(Sender: TObject);
begin
  DF1Edit.Visible := CompareDist <> cd_Normal;
  DF1Label.Visible := DF1Edit.Visible;
  DF1Label.Caption := 'D.F.';

  DF2Edit.Visible := CompareDist = cd_F;
  DF2Label.Visible := DF2Edit.Visible;

  if NormalDistChk.Checked then
    CompareDist := cd_Normal
  else if tDistChk.Checked then
  begin
    CompareDist := cd_t;
    UpdateDF1;
  end
  else if ChiSqDistChk.Checked then
    CompareDist := cd_ChiSq
  else if FDistChk.Checked then
  begin
    CompareDist := cd_F;
    DF1Label.Caption := 'D.F. 1';
  end
  else if PoissonDistChk.Checked then
  begin
    CompareDist := cd_Poisson;
    DF1Label.Caption := 'Mean';
    UpdateDF1;
  end else
    raise Exception.Create('Distribution not supported.');
end;


procedure TCompareDistFrm.FormActivate(Sender: TObject);
var
  w: Integer;
begin
   if FAutoSized then
     exit;

   w := MaxValue([ResetBtn.Width, ComputeBtn.Width, CloseBtn.Width]);
  ResetBtn.Constraints.MinWidth := w;
  ComputeBtn.Constraints.MinWidth := w;
  CloseBtn.Constraints.MinWidth := w;

  Notebook.AutoSize := true;
  ParamsPanel.Constraints.MinWidth := Max(
    3*w + 2*CloseBtn.BorderSpacing.Left,
    Min(
      CompareGroup.Width * 2 - Var1InBtn.Width + VarList.BorderSpacing.Right,
      OptionsGroup.Width)
  );
  ParamsPanel.Constraints.MinHeight :=  Notebook.Top + Notebook.Height +
    OptionsGroup.BorderSpacing.Top + OptionsGroup.Height + Bevel1.Height +
    CloseBtn.Height + CloseBtn.BorderSpacing.Top;

  Constraints.MinWidth := ParamsPanel.Constraints.MinWidth + 300;
  Constraints.MinHeight := ParamsPanel.Constraints.MinHeight + ParamsPanel.BorderSpacing.Top * 2;
  if Width < Constraints.MinWidth then Width := 1;
  if Height < Constraints.MinHeight then Height := 1;

//  Notebook.AutoSize := false;
  Position := poDesigned;
  FAutoSized := true;
end;


procedure TCompareDistFrm.FormCreate(Sender: TObject);
begin
  Assert(OS3MainFrm <> nil);
  if GraphFrm = nil then Application.CreateForm(TGraphFrm, GraphFrm);

  InitForm(self);

  FReportFrame := TReportFrame.Create(self);
  FReportFrame.Parent := ReportPage;
  FReportFrame.Align := alClient;

  FCumFreqChartFrame := TChartFrame.Create(self);
  FCumFreqChartFrame.Parent := CumFreqChartPage;
  FCumFreqChartFrame.Align := alClient;
  FCumFreqChartFrame.Chart.BottomAxis.Intervals.MaxLength := 80;
  FCumFreqChartFrame.Chart.BottomAxis.Intervals.MinLength := 30;
  FCumFreqChartFrame.SetYTitle('Cumulative frequency');
  FCumFreqChartFrame.SetTitle('Plot of Cumulative Distributions');

  FFreqChartFrame := TChartFrame.Create(self);
  FFreqChartFrame.Parent := FreqChartPage;
  FFreqChartFrame.Align := alClient;
  FFreqChartFrame.Chart.BottomAxis.Intervals.MaxLength := 80;
  FFreqChartFrame.Chart.BottomAxis.Intervals.MinLength := 30;
  FFreqChartFrame.SetYTitle('Frequency');
  FFreqChartFrame.SetTitle('Plot of Distributions');

  Reset;
end;


procedure TCompareDistFrm.Plot(AChartFrame: TChartFrame; Y1Values, Y2Values: DblDyneVec;
  AName1, AName2: String);
var
  ser1, ser2: TChartSeries;
  plotType: TPlotType;
begin
  AChartFrame.Clear;

  if BarPlotBtn.Down then
    plotType := ptBars
  else
    plotType := ptLines;

  ser1 := AChartFrame.PlotXY(plotType, nil, Y1Values, nil, nil, AName1, DATA_COLORS[0]);
  ser2 := AChartFrame.PlotXY(plotType, nil, Y2Values, nil, nil, AName2, DATA_Colors[1]);

  if (ser1 is TBarSeries) then
  begin
    with ser1 as TBarSeries do
    begin
      BarWidthPercent := 40;
      BarOffsetPercent := -20;
    end;
    with ser2 as TBarSeries do
    begin
      BarWidthPercent := 40;
      BarOffsetPercent := +20;
    end;
  end;
end;


procedure TCompareDistFrm.Reset;
var
  i: integer;
begin
  VarList.Clear;

  VarOneEdit.Text := '';
  VarTwoEdit.Text := '';
  DF1Edit.Text := '';
  DF2Edit.Text := '';

  for i := 1 to NoVariables do
    VarList.Items.Add(OS3MainFrm.DataGrid.Cells[i,0]);

  CompareGroup.ItemIndex := 0;
  CompareGroupClick(nil);
  NormalDistChk.Checked := true;
  DistChange(nil);

  FReportFrame.Clear;
  FCumFreqChartFrame.Clear;
  FFreqChartFrame.Clear;
  FreqChartPage.TabVisible := false;
end;


procedure TCompareDistFrm.ResetBtnClick(Sender: TObject);
begin
  Reset;
end;


procedure TCompareDistFrm.UpdateBtnStates;
begin
  Var1InBtn.Enabled := (VarList.ItemIndex > -1) and (VarOneEdit.Text = '');
  Var2InBtn.Enabled := (VarList.ItemIndex > -1) and (VarTwoEdit.Text = '');
  Var1OutBtn.Enabled := VarOneEdit.Text <> '';
  Var2OutBtn.Enabled := VarTwoEdit.Text <> '';

  FReportFrame.UpdateBtnStates;
  FCumFreqChartFrame.UpdateBtnStates;
  FFreqChartFrame.UpdateBtnStates;
end;


procedure TCompareDistFrm.UpdateDF1;

  procedure DFCandidates(AVarName: String; out AMean: Double; out ANumCases: Integer);
  var
    col, i: Integer;
  begin
    for col := 1 to NoVariables do
      if AVarName = OS3MainFrm.DataGrid.Cells[col, 0] then
      begin
        AMean := 0;
        ANumCases := 0;
        for i := 1 to NoCases do
          if ValidValue(i, col) then
          begin
            AMean := AMean + StrToFloat(OS3MainFrm.DataGrid.Cells[col, i]);
            inc(ANumCases);
          end;
        if ANumCases > 1 then
          AMean := AMean / ANumCases
        else
          AMean := NaN;
        exit;
      end;
    AMean := NaN;
    ANumCases := -1;
  end;

var
  m: Double;
  n: Integer;
begin
  if (CompareTo = ctTheoreticalDistrib) then
  begin
    DFCandidates(VarOneEdit.Text, m, n);
    case CompareDist of
      cd_t :
        if n > 0 then
          DF1Edit.Text := IntToStr(n-1);
      cd_Poisson:
        if not IsNaN(m) then
          DF1Edit.Text := FormatFloat('0', m);
    end;
  end;
end;


function TCompareDistFrm.Validate(ANumCases: Integer;
  out AMsg: String; out AControl: TWinControl): Boolean;
var
  n: Integer = 0;
begin
  Result := false;

  if CompareDist <> cd_Normal then
  begin
    if DF1Edit.Text = '' then
    begin
      AMsg := 'This control cannot be empty.';
      AControl := DF1Edit;
      exit;
    end;
    if not TryStrToInt(DF1Edit.Text, n) or (n < 0) then
    begin
      AMsg := 'Positive integer value required.';
      AControl := DF1Edit;
      exit;
    end;
    if (n >= ANumCases) and (CompareDist <> cd_Poisson) then
    begin
      AMsg := 'Degrees of freedom cannot be greater than the number of cases.';
      AControl := DF1Edit;
      exit;
    end;
  end;

  if CompareDist = cd_F then
  begin
    if DF2Edit.Text = '' then
    begin
      AMsg := 'This control cannot be empty.';
      AControl := DF2Edit;
      exit;
    end;
    if not TryStrToInt(DF2Edit.Text, n) or (n < 0) then
    begin
      AMsg := 'Positive integer value required.';
      AControl := DF2Edit;
      exit;
    end;
    if n >= ANumCases then
    begin
      AMsg := 'Degrees of freedom cannot be greater than the number of cases.';
      AControl := DF2Edit;
      exit;
    end;
  end;

  Result := true;
end;


procedure TCompareDistFrm.Var1InBtnClick(Sender: TObject);
var
  i: integer;
begin
  i := 0;
  while (VarOneEdit.Text = '') and (i < VarList.Items.Count) do
  begin
    if VarList.Selected[i] then
    begin
      VarOneEdit.Text := VarList.Items[i];
      VarList.Items.Delete(i);
      i := 0;
    end else
      inc(i);
  end;
  UpdateBtnStates;
  UpdateDF1;
end;


procedure TCompareDistFrm.Var1OutBtnClick(Sender: TObject);
begin
  if VarOneEdit.Text <> '' then
  begin
    VarList.Items.Add(VarOneEdit.Text);
    VarOneEdit.Text := '';
  end;
  UpdateBtnStates;
end;


procedure TCompareDistFrm.Var2InBtnClick(Sender: TObject);
var
  i: integer;
begin
  i := 0;
  while (VarTwoEdit.Text = '') and (i < VarList.Items.Count) do
  begin
    if VarList.Selected[i] then
    begin
      VarTwoEdit.Text := VarList.Items[i];
      VarList.Items.Delete(i);
      i := 0;
    end else
      inc(i);
  end;
  UpdateBtnStates;
end;


procedure TCompareDistFrm.Var2OutBtnClick(Sender: TObject);
begin
  if VarTwoEdit.Text <> '' then
  begin
    VarList.Items.Add(VarTwoEdit.Text);
    VarTwoEdit.Text := '';
  end;
  UpdateBtnStates;
end;


procedure TCompareDistFrm.VarListDblClick(Sender: TObject);
var
  index: Integer;
begin
  index := VarList.ItemIndex;
  if (index > -1) then
  begin
    if VarOneEdit.Text = '' then
    begin
      VarOneEdit.Text := VarList.Items[index];
      VarList.Items.Delete(index);
    end;
    if CompareGroup.ItemIndex = 1 then  // Compare to another variable
    begin
      VarTwoEdit.Text := VarList.Items[index];
      VarList.Items.Delete(index);
    end;
    UpdateBtnStates;
  end;
end;


procedure TCompareDistFrm.VarListSelectionChange(Sender: TObject; User: boolean);
begin
  UpdateBtnStates;
end;


end.