68 lines
1.5 KiB
ObjectPascal
68 lines
1.5 KiB
ObjectPascal
program CholeskyApp;
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type
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D2Array = array of array of double;
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function cholesky(const A: D2Array): D2Array;
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var
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i, j, k: integer;
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s: double;
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begin
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setlength(Result, length(A), length(A));
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for i := low(Result) to high(Result) do
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for j := 0 to i do
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begin
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s := 0;
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for k := 0 to j - 1 do
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s := s + Result[i][k] * Result[j][k];
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if i = j then
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Result[i][j] := sqrt(A[i][i] - s)
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else
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Result[i][j] := (A[i][j] - s) / Result[j][j]; // save one multiplication compared to the original
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end;
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end;
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procedure printM(const A: D2Array);
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var
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i, j: integer;
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begin
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for i := low(A) to high(A) do
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begin
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for j := low(A) to high(A) do
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write(A[i, j]: 8: 5);
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writeln;
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end;
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end;
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const
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m1: array[0..2, 0..2] of double = ((25, 15, -5), (15, 18, 0), (-5, 0, 11));
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m2: array[0..3, 0..3] of double = ((18, 22, 54, 42), (22, 70, 86, 62), (54, 86,
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174, 134), (42, 62, 134, 106));
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var
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index, i: integer;
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cIn, cOut: D2Array;
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begin
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setlength(cIn, length(m1), length(m1));
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for index := low(m1) to high(m1) do
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begin
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SetLength(cIn[index], length(m1[index]));
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for i := 0 to High(m1[Index]) do
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cIn[index][i] := m1[index][i];
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end;
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cOut := cholesky(cIn);
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printM(cOut);
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writeln;
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setlength(cIn, length(m2), length(m2));
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for index := low(m2) to high(m2) do
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begin
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SetLength(cIn[index], length(m2[Index]));
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for i := 0 to High(m2[Index]) do
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cIn[index][i] := m2[index][i];
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end;
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cOut := cholesky(cIn);
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printM(cOut);
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end.
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