A RMS functions to Maths category

delphidabbler · delphidabbler · commit 56222ce800b4 · 2025-01-18T09:50:34.000Z
Added Double &amp; Integer overloads of the RMS function.

Added a source code file for each overload.

Updated maths.ini with the meta data for each function.
diff --git a/collection/702.dat b/collection/702.dat
@@ -0,0 +1,11 @@
+﻿function RMS(const A: array of Double): Double; overload;
+var
+  Squares: array of Double;
+  Idx: Integer;
+begin
+  System.SetLength(Squares, System.Length(A));
+  for Idx := 0 to Pred(System.Length(A)) do
+    Squares[Idx] := A[Idx] * A[Idx];
+  // Note: ArithmeticMean raises exception if A is empty
+  Result := Math.Power(ArithmeticMean(Squares), 0.5);
+end;
diff --git a/collection/703.dat b/collection/703.dat
@@ -0,0 +1,16 @@
+﻿function RMS(const A: array of Integer): Double; overload;
+var
+  Squares: array of Double;
+  Idx: Integer;
+  Elem: Double;
+begin
+  System.SetLength(Squares, System.Length(A));
+  for Idx := 0 to Pred(System.Length(A)) do
+  begin
+    // convert Integer to Double before squaring to reduce change of overflow
+    Elem := A[Idx];
+    Squares[Idx] := Elem * Elem;
+  end;
+  // Note: ArithmeticMean raises exception if A is empty
+  Result := Math.Power(ArithmeticMean(Squares), 0.5);
+end;
diff --git a/collection/maths.ini b/collection/maths.ini
@@ -2387,3 +2387,31 @@ AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tes
 Snip=701.dat
 DelphiXE=Y
 Delphi12A=Y
+
+[RMS_Double]
+DisplayName="RMS (Double overload)"
+DescEx="<p>Calculates the root mean square of the elements of <var>Double</var> floating point array <var>A</var>.</p><p>Raises <var>EArgumentException</var> if <var>A</var> is empty.</p>"
+Kind=routine
+Units=SysUtils,Math
+Depends=ArithmeticMean_Double
+SeeAlso=RMS_Integer
+TestInfo=advanced
+AdvancedTest.Level=unit-tests
+AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tests/Cat-Maths"
+Snip=702.dat
+DelphiXE=Y
+Delphi12A=Y
+
+[RMS_Integer]
+DisplayName="RMS (Integer overload)"
+DescEx="<p>Calculates the root mean square of the elements of <var>Integer</var> array <var>A</var>.</p><p>Raises <var>EArgumentException</var> if <var>A</var> is empty.</p>"
+Kind=routine
+Units=SysUtils,Math
+Depends=ArithmeticMean_Double
+SeeAlso=RMS_Double
+TestInfo=advanced
+AdvancedTest.Level=unit-tests
+AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tests/Cat-Maths"
+Snip=703.dat
+DelphiXE=Y
+Delphi12A=Y
