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LazStats: Some refactoring of SPC chart units

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git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7666 8e941d3f-bd1b-0410-a28a-d453659cc2b4
This commit is contained in:
wp_xxyyzz
2020-09-14 09:51:42 +00:00
parent 980c4033d0
commit 65f0e63af1
4 changed files with 60 additions and 37 deletions
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19
applications/lazstats/source/forms/analysis/statistical_process_control/basicspcunit.pas
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@ -93,24 +93,6 @@ type
var
BasicSPCForm: TBasicSPCForm;
// Constants for correction of standard deviation, needed by some charts.
const
C4: array[2..25] of double = (
0.7979, 0.8862, 0.9213, 0.9400, 0.9515, 0.9594, 0.9650, 0.9693,
0.9727, 0.9754, 0.9776, 0.9794, 0.9810, 0.9823, 0.9835, 0.9845, 0.9854, 0.9862,
0.9869, 0.9876, 0.9882, 0.9887, 0.9892, 0.9896);
D3: array[1..24] of double = (
0, 0, 0, 0, 0, 0.076, 0.136, 0.184, 0.223, 0.256, 0.283, 0.307, 0.328,
0.347, 0.363, 0.378, 0.391, 0.403, 0.415, 0.425, 0.434, 0.443,
0.451, 0.459
);
D4: array[1..24] of double = (
3.267, 2.574, 2.282, 2.114, 2.004, 1.924, 1.864, 1.816, 1.777,
1.744, 1.717, 1.693, 1.672, 1.653, 1.637, 1.622, 1.608, 1.597,
1.585, 1.575, 1.566, 1.557, 1.548, 1.541
);
implementation
@ -139,6 +121,7 @@ begin
end;
// To be overridden by descendant forms
procedure TBasicSPCForm.Compute;
begin
//

17
applications/lazstats/source/forms/analysis/statistical_process_control/rchartunit.pas
View File

@ -25,6 +25,19 @@ uses
Math,
Globals, Utils, MainUnit, DataProcs;
// Constants for correction of standard deviation
const
D3: array[2..25] of double = (
0, 0, 0, 0, 0, 0.076, 0.136, 0.184, 0.223, 0.256, 0.283, 0.307, 0.328,
0.347, 0.363, 0.378, 0.391, 0.403, 0.415, 0.425, 0.434, 0.443,
0.451, 0.459
);
D4: array[2..25] of double = (
3.267, 2.574, 2.282, 2.114, 2.004, 1.924, 1.864, 1.816, 1.777,
1.744, 1.717, 1.693, 1.672, 1.653, 1.637, 1.622, 1.608, 1.597,
1.585, 1.575, 1.566, 1.557, 1.548, 1.541
);
procedure TRChartForm.Compute;
var
i, j: Integer;
@ -116,8 +129,8 @@ begin
seMean := seMean / sqrt(numValues);
grandMean := grandMean / numValues;
grandRange := grandRange / numGrps;
D3Value := D3[grpSize-1];
D4Value := D4[grpSize-1];
D3Value := D3[grpSize];
D4Value := D4[grpSize];
UCL := D4Value * grandRange;
LCL := D3Value * grandRange;

40
applications/lazstats/source/forms/analysis/statistical_process_control/schartunit.pas
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@ -1,3 +1,11 @@
{ This unit was checked against a commercial statistical software and
creates correct results.
Data file for testing: "boltsize.laz"
Group variable: LotNo
Selected variable: BoltLngth
}
unit SChartUnit;
{$mode objfpc}{$H+}
@ -40,11 +48,9 @@ var
numValues: Integer = 0;
grp: String;
grpIndex: Integer;
X, Xsq: Double;
X, Xsq, Xmin, Xmax: Double;
seMean, grandMean, grandSigma, grandSD: Double;
B, C4, gamma, D3Value, D4Value: Double;
xmin, xmax: Double;
sizeError: Boolean;
B, C4: Double;
i, j: Integer;
lReport: TStrings;
begin
@ -63,7 +69,6 @@ begin
seMean := 0.0;
grandMean := 0.0;
grandSigma := 0.0;
sizeError := false;
// Count "good" data points
numValues := 0;
@ -101,12 +106,15 @@ begin
grpSize := count[j];
if j = 0 then oldGrpSize := grpSize;
if oldGrpSize <> grpSize then
sizeError := true;
begin
ErrorMsg('All groups must have the same size.');
exit;
end;
end;
if (grpSize < 2) or (grpSize > 25) or sizeError then
if (grpSize < 2) then
begin
ErrorMsg('Group size error.');
ErrorMsg('Groups with at least two values required.');
exit;
end;
@ -117,14 +125,9 @@ begin
seMean := seMean / sqrt(numValues);
grandMean := grandMean / numValues;
grandSigma := grandSigma / numGrps;
D3Value := D3[grpSize-1];
D4Value := D4[grpSize-1];
C4 := sqrt(2.0 / (grpSize - 1));
gamma := exp(GammaLn(grpSize / 2.0));
C4 := C4 * gamma;
gamma := exp(GammaLn((grpSize-1) / 2.0));
C4 := C4 / gamma;
B := grandSigma * sqrt(1.0 - (C4 * C4)) / C4;
C4 := CalcC4(grpSize);
B := grandSigma * sqrt(1.0 - sqr(C4)) / C4;
UCL := grandSigma + 3.0 * B;
LCL := grandSigma - 3.0 * B;
if (LCL < 0.0) then LCL := 0.0;
@ -135,6 +138,9 @@ begin
lReport.Add('Sigma Chart Results');
lReport.Add('');
lReport.Add('Number of values: %8d', [numValues]);
lReport.Add('Number of groups: %8d', [numGrps]);
lReport.Add('Group size: %8d', [grpSize]);
lReport.Add('');
lReport.Add('Grand Mean: %8.3f', [grandMean]);
lReport.Add('Standard Deviation: %8.3f', [grandSD]);
lReport.Add('Standard Error of Mean: %8.3f', [seMean]);
@ -157,7 +163,7 @@ begin
PlotMeans(
Format('Sigma Chart for "%s"', [GetFileName]),
GroupEdit.Text, Format('StdDev(%s)', [MeasEdit.Text]),
'Group Sigma', 'Mean',
'Group Sigma', 'Avg',
groups, stdDev,
UCL, LCL, grandSigma,
NaN, NaN, NaN

21
applications/lazstats/source/units/mathunit.pas
View File

@ -25,6 +25,8 @@ function FDensity(x: Double; DF1, DF2: Integer): Double;
function Chi2Density(x: Double; N: Integer): Double;
function CalcC4(n: Integer): Double;
implementation
uses
@ -286,5 +288,24 @@ begin
Result := power(x, (N-2.0) * 0.5) / (factor * exp(x * 0.5));
end;
// Returns the value of the C4 factor needed for correction of standard deviations
// C4 = sqrt(2 / (n-1)) (n/2-1)! / ((n-1)/2-1)!
function CalcC4(n: Integer): Double;
var
gamma1, gamma2: Double;
begin
gamma1 := GammaLn(n/2);
gamma2 := GammaLn((n-1)/2);
Result := sqrt(2.0 / (n-1)) * exp(gamma1 - gamma2);
{
C4 := sqrt(2.0 / (grpSize - 1));
gamma := exp(GammaLn(grpSize / 2.0));
C4 := C4 * gamma;
gamma := exp(GammaLn((grpSize-1) / 2.0));
C4 := C4 / gamma;
}
end;
end.