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Merge branch 'feature/49-rms-function' into develop
Fixes #49
2 parents 8196a2e + 3f003fb commit 9c411d5

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5 files changed

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lines changed

5 files changed

+163
-1
lines changed

‎collection/702.dat

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,11 @@
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function RMS(const A: array of Double): Double; overload;
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var
3+
Squares: array of Double;
4+
Idx: Integer;
5+
begin
6+
System.SetLength(Squares, System.Length(A));
7+
for Idx := 0 to Pred(System.Length(A)) do
8+
Squares[Idx] := A[Idx] * A[Idx];
9+
// Note: ArithmeticMean raises exception if A is empty
10+
Result := Math.Power(ArithmeticMean(Squares), 0.5);
11+
end;

‎collection/703.dat

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,16 @@
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function RMS(const A: array of Integer): Double; overload;
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var
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Squares: array of Double;
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Idx: Integer;
5+
Elem: Double;
6+
begin
7+
System.SetLength(Squares, System.Length(A));
8+
for Idx := 0 to Pred(System.Length(A)) do
9+
begin
10+
// convert Integer to Double before squaring to reduce change of overflow
11+
Elem := A[Idx];
12+
Squares[Idx] := Elem * Elem;
13+
end;
14+
// Note: ArithmeticMean raises exception if A is empty
15+
Result := Math.Power(ArithmeticMean(Squares), 0.5);
16+
end;

‎collection/maths.ini

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2387,3 +2387,31 @@ AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tes
23872387
Snip=701.dat
23882388
DelphiXE=Y
23892389
Delphi12A=Y
2390+
2391+
[RMS_Double]
2392+
DisplayName="RMS (Double overload)"
2393+
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>"
2394+
Kind=routine
2395+
Units=SysUtils,Math
2396+
Depends=ArithmeticMean_Double
2397+
SeeAlso=RMS_Integer
2398+
TestInfo=advanced
2399+
AdvancedTest.Level=unit-tests
2400+
AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tests/Cat-Maths"
2401+
Snip=702.dat
2402+
DelphiXE=Y
2403+
Delphi12A=Y
2404+
2405+
[RMS_Integer]
2406+
DisplayName="RMS (Integer overload)"
2407+
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>"
2408+
Kind=routine
2409+
Units=SysUtils,Math
2410+
Depends=ArithmeticMean_Double
2411+
SeeAlso=RMS_Double
2412+
TestInfo=advanced
2413+
AdvancedTest.Level=unit-tests
2414+
AdvancedTest.URL="https://github.com/delphidabbler/code-snippets/tree/master/tests/Cat-Maths"
2415+
Snip=703.dat
2416+
DelphiXE=Y
2417+
Delphi12A=Y

‎tests/Cat-Maths/TestUMathsCatSnippets.pas

Lines changed: 56 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -84,6 +84,8 @@ TestMathsCatSnippets = class(TTestCase)
8484
procedure TestHasMode_ExceptSingleElementArray;
8585
procedure TestModeCount_ExceptEmptyArray;
8686
procedure TestModeCount_ExceptSingleElementArray;
87+
procedure TestRMS_Double_ExceptEmptyArray;
88+
procedure TestRMS_Integer_ExceptEmptyArray;
8789
function EqualArrays(const Left, Right: TBytes): Boolean; overload;
8890
function EqualArrays(const Left, Right: array of Integer): Boolean;
8991
overload;
@@ -187,6 +189,8 @@ TestMathsCatSnippets = class(TTestCase)
187189
procedure TestModeAlt;
188190
procedure TestHasMode;
189191
procedure TestModeCount;
192+
procedure TestRMS_Double;
193+
procedure TestRMS_Integer;
190194
end;
191195

192196
implementation
@@ -2418,6 +2422,58 @@ procedure TestMathsCatSnippets.TestResizeRect_B;
24182422
CheckEquals(-4, RectHeight(R), '3: RectHeight');
24192423
end;
24202424

2425+
procedure TestMathsCatSnippets.TestRMS_Double;
2426+
const
2427+
Fudge = 0.0001;
2428+
A: array[1..4] of Double = (23.45, 35.786, 87326.948, 13);
2429+
B: array[1..8] of Double = (-19.0, 27.890, -42.83729, 56.73829, 100.0, -100.0, 0.0, 666.6);
2430+
C: array[1..3] of Double = (0.0, 0.0, 0.0);
2431+
D: array[1..1] of Double = (2345.67889);
2432+
E: array[1..2] of Double = (-999.99, +999.99);
2433+
begin
2434+
// Some expected results from https://miniwebtool.com/root-mean-square-calculator/
2435+
CheckEquals(43663.47973, RMS(A), Fudge, 'A');
2436+
CheckEquals(242.5254314, RMS(B), Fudge, 'B');
2437+
CheckEquals(0.0, RMS(C), Fudge, 'C');
2438+
CheckEquals(2345.67889, RMS(D), Fudge, 'D');
2439+
CheckEquals(999.99, RMS(E), Fudge, 'E');
2440+
CheckException(TestRMS_Double_ExceptEmptyArray, EArgumentException, 'Empty array');
2441+
end;
2442+
2443+
procedure TestMathsCatSnippets.TestRMS_Double_ExceptEmptyArray;
2444+
var
2445+
A: array of Double;
2446+
begin
2447+
SetLength(A, 0);
2448+
RMS(A);
2449+
end;
2450+
2451+
procedure TestMathsCatSnippets.TestRMS_Integer;
2452+
const
2453+
Fudge = 0.0001;
2454+
A: array[1..4] of Integer = (23, 36, 87327, 13);
2455+
B: array[1..8] of Integer = (-19, 28, -43, 57, 100, -100, 0, 666);
2456+
C: array[1..3] of Integer = (0, 0, 0);
2457+
D: array[1..1] of Integer = (2346);
2458+
E: array[1..2] of Integer = (-999, +999);
2459+
begin
2460+
// Some expected results from https://miniwebtool.com/root-mean-square-calculator/
2461+
CheckEquals(43663.505708428864, RMS(A), Fudge, 'A');
2462+
CheckEquals(242.3321584, RMS(B), Fudge, 'B');
2463+
CheckEquals(0.0, RMS(C), Fudge, 'C');
2464+
CheckEquals(2346.0, RMS(D), Fudge, 'D');
2465+
CheckEquals(999.0, RMS(E), Fudge, 'E');
2466+
CheckException(TestRMS_Integer_ExceptEmptyArray, EArgumentException, 'Empty array');
2467+
end;
2468+
2469+
procedure TestMathsCatSnippets.TestRMS_Integer_ExceptEmptyArray;
2470+
var
2471+
A: array of Integer;
2472+
begin
2473+
SetLength(A, 0);
2474+
RMS(A);
2475+
end;
2476+
24212477
procedure TestMathsCatSnippets.TestSoftMax;
24222478

24232479
function ArraysEqual(const Left, Right: array of Double): Boolean;

‎tests/Cat-Maths/UMathsCatSnippets.pas

Lines changed: 52 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* The unit is copyright © 2005-2025 by Peter Johnson & Contributors and is
77
* licensed under the MIT License (https://opensource.org/licenses/MIT).
88
*
9-
* Generated on : Fri, 17 Jan 2025 09:41:35 GMT.
9+
* Generated on : Sat, 18 Jan 2025 09:49:49 GMT.
1010
* Generated by : DelphiDabbler CodeSnip Release 4.24.0.
1111
*
1212
* The latest version of CodeSnip is available from the CodeSnip GitHub project
@@ -669,6 +669,19 @@ function ReverseNumber(AValue: Int64): Int64;
669669
}
670670
function ReverseNumberR(AValue: Int64): Int64;
671671

672+
{
673+
Calculates the root mean square of the elements of Double floating point array
674+
A.
675+
Raises EArgumentException if A is empty.
676+
}
677+
function RMS(const A: array of Double): Double; overload;
678+
679+
{
680+
Calculates the root mean square of the elements of Integer array A.
681+
Raises EArgumentException if A is empty.
682+
}
683+
function RMS(const A: array of Integer): Double; overload;
684+
672685
{
673686
Performs an arithmetic right shift operation on the given value and returns
674687
the result. Value is shifted right by Shift bits.
@@ -2838,6 +2851,44 @@ function ReverseNumberR(AValue: Int64): Int64;
28382851
+ ReverseNumberR(AValue div 10)
28392852
end;
28402853

2854+
{
2855+
Calculates the root mean square of the elements of Double floating point array
2856+
A.
2857+
Raises EArgumentException if A is empty.
2858+
}
2859+
function RMS(const A: array of Double): Double; overload;
2860+
var
2861+
Squares: array of Double;
2862+
Idx: Integer;
2863+
begin
2864+
System.SetLength(Squares, System.Length(A));
2865+
for Idx := 0 to Pred(System.Length(A)) do
2866+
Squares[Idx] := A[Idx] * A[Idx];
2867+
// Note: ArithmeticMean raises exception if A is empty
2868+
Result := Math.Power(ArithmeticMean(Squares), 0.5);
2869+
end;
2870+
2871+
{
2872+
Calculates the root mean square of the elements of Integer array A.
2873+
Raises EArgumentException if A is empty.
2874+
}
2875+
function RMS(const A: array of Integer): Double; overload;
2876+
var
2877+
Squares: array of Double;
2878+
Idx: Integer;
2879+
Elem: Double;
2880+
begin
2881+
System.SetLength(Squares, System.Length(A));
2882+
for Idx := 0 to Pred(System.Length(A)) do
2883+
begin
2884+
// convert Integer to Double before squaring to reduce change of overflow
2885+
Elem := A[Idx];
2886+
Squares[Idx] := Elem * Elem;
2887+
end;
2888+
// Note: ArithmeticMean raises exception if A is empty
2889+
Result := Math.Power(ArithmeticMean(Squares), 0.5);
2890+
end;
2891+
28412892
{
28422893
Performs an arithmetic right shift operation on the given value and returns
28432894
the result. Value is shifted right by Shift bits.

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