From 5e3a6832992142065e7c9b2c468d58d9fe3ee87a Mon Sep 17 00:00:00 2001
From: wp <wp.no-reply@lazarus-ide-org>
Date: Mon, 20 Aug 2018 23:01:37 +0000
Subject: [PATCH] TAChart: Add fit parameter confidence limits to FitSeries.

git-svn-id: trunk@58747 -
---
 components/tachart/demo/fit/Main.lfm |  4 ++--
 components/tachart/demo/fit/Main.pas | 20 ++++++++++++++++++++
 components/tachart/tafuncseries.pas  | 22 ++++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/components/tachart/demo/fit/Main.lfm b/components/tachart/demo/fit/Main.lfm
index 557ec9f86d..ac48a66071 100644
--- a/components/tachart/demo/fit/Main.lfm
+++ b/components/tachart/demo/fit/Main.lfm
@@ -25,9 +25,9 @@ object frmMain: TfrmMain
       Height = 487
       Top = 0
       Width = 400
-      ActivePage = TabSheet2
+      ActivePage = TabSheet1
       Align = alClient
-      TabIndex = 1
+      TabIndex = 0
       TabOrder = 0
       object TabSheet1: TTabSheet
         Caption = 'Preparation'
diff --git a/components/tachart/demo/fit/Main.pas b/components/tachart/demo/fit/Main.pas
index 66fe292398..5c52f2380c 100644
--- a/components/tachart/demo/fit/Main.pas
+++ b/components/tachart/demo/fit/Main.pas
@@ -378,6 +378,7 @@ procedure TfrmMain.FitCompleteHandler(Sender:TObject);
 const
   {$IF FPC_FullVersion >= 30004}
   MASK = '%-4s %10s %10s %10s %10s';
+  CONF_MASK = '%-4s %10s %10s %10s';
   {$ELSE}
   MASK = '%-4s %10s %10s %10s';
   {$IFEND}
@@ -389,6 +390,7 @@ var
   L: Integer;
   decsep: Char;
   paramName: String;
+  confL, confH: Double;
 begin
   decsep := DefaultFormatSettings.DecimalSeparator;
   with lbResults.Items do begin
@@ -421,6 +423,24 @@ begin
               ]));
             end;
             Add('');
+            {$IF FPC_FullVersion >= 30004}
+            Add('CONFIDENCE LIMITS');
+            Add(Format(CONF_MASK, ['Name', 'Value', 'Lower', 'Upper']));
+            for i := 0 to FitSeries.ParamCount - 1 do begin
+              case FitSeries.FitEquation of
+                fePolynomial: paramname := Format('b[%d]', [i]);
+                else          paramname := PARAM_NAME[i];
+              end;
+              FitSeries.GetConfidenceLimits(i, confL, confH);
+              Add(Format(CONF_MASK, [
+                paramName,
+                MyFormatFloat(FitSeries.Param[i], STD_FMT, EXP_FMT),
+                MyFormatFloat(confL, STD_FMT, EXP_FMT),
+                MyFormatFloat(confH, STD_FMT, EXP_FMT)
+              ]));
+            end;
+            Add('');
+            {$IFEND}
             Add('ANALYSIS OF VARIANCE');
             lbResults.Canvas.Font.Assign(lbResults.Font);
             FReportDecimals := 5;
diff --git a/components/tachart/tafuncseries.pas b/components/tachart/tafuncseries.pas
index 92f00e0ef0..db701243e8 100644
--- a/components/tachart/tafuncseries.pas
+++ b/components/tachart/tafuncseries.pas
@@ -335,6 +335,9 @@ type
     procedure ExecFit; virtual;
     function EquationText: IFitEquationText;
     function FitParams: TDoubleDynArray;
+    {$IF FPC_FullVersion >= 30004}
+    procedure GetConfidenceLimits(AIndex: Integer; out ALower, AUpper: Double);
+    {$IFEND}
     function GetFitEquationString(
       ANumFormat: String; AXText: String = 'x'; AYText: String = 'y'): String;
       deprecated 'Use EquationText';
@@ -1721,6 +1724,25 @@ begin
     Result[i] := Param[i];
 end;
 
+{$IF FPC_FullVersion >= 30004}
+procedure TFitSeries.GetConfidenceLimits(AIndex: Integer; out ALower, AUpper: Double);
+var
+  val, sig, t: Double;
+  alpha: Double;
+begin
+  val := GetParam_RawValue(AIndex);
+  sig := GetParam_RawError(AIndex);
+  alpha := 1.0 - FConfidenceLevel;
+  t := invtdist(alpha, Statistics.DOF, 2);
+  ALower := val - sig*t;
+  AUpper := val + sig*t;
+  if (FFitEquation in [feExp, fePower]) and (AIndex = 0) then begin
+    ALower := exp(ALower);
+    AUpper := exp(AUpper);
+  end;
+end;
+{$IFEND}
+
 function TFitSeries.GetFitEquationString(ANumFormat: String; AXText: String;
   AYText: String): String;
 begin