From ab453b347d30d5dc30afa7104c9bbd4ac90b7ee9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20M=C3=BCller?= <stefan.mueller@aksdb.de>
Date: Sun, 26 May 2024 14:23:31 +0200
Subject: [PATCH] Renamed root finding class and methods, now class methods

---
 UPolynomialRoots.pas                | 33 ++++++++++++++++-------------
 tests/UPolynomialRootsTestCases.pas | 20 ++---------------
 2 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/UPolynomialRoots.pas b/UPolynomialRoots.pas
index 3d9fafa..2a522f0 100644
--- a/UPolynomialRoots.pas
+++ b/UPolynomialRoots.pas
@@ -37,22 +37,23 @@ type
 
   TIsolatingIntervals = specialize TList<TIsolatingInterval>;
 
-  { TRootIsolation }
+  { TPolynomialRoots }
 
-  TRootIsolation = class
+  TPolynomialRoots = class
   private
-    function CalcSimpleRootBound(constref APolynomial: TBigIntPolynomial): TBigInt;
-    function GetIsolatingInterval(const AC, AK, AH: Cardinal; constref ABound: TBigInt): TIsolatingInterval;
+    class function CalcUpperRootBound(constref APolynomial: TBigIntPolynomial): TBigInt;
+    class function CreateIsolatingInterval(const AC, AK, AH: Cardinal; constref ABound: TBigInt): TIsolatingInterval;
   public
-    function Bisect(constref APolynomial: TBigIntPolynomial): TIsolatingIntervals;
-    function Bisect(constref APolynomial: TBigIntPolynomial; constref ABound: TBigInt): TIsolatingIntervals;
+    class function BisectIsolation(constref APolynomial: TBigIntPolynomial): TIsolatingIntervals;
+    class function BisectIsolation(constref APolynomial: TBigIntPolynomial; constref ABound: TBigInt):
+      TIsolatingIntervals;
   end;
 
 implementation
 
-{ TRootIsolation }
+{ TPolynomialRoots }
 
-function TRootIsolation.CalcSimpleRootBound(constref APolynomial: TBigIntPolynomial): TBigInt;
+class function TPolynomialRoots.CalcUpperRootBound(constref APolynomial: TBigIntPolynomial): TBigInt;
 var
   i, sign: Integer;
   an, ai, max: TBigInt;
@@ -76,7 +77,8 @@ begin
   Result := TBigInt.One << (numeratorBit - denominatorBit);
 end;
 
-function TRootIsolation.GetIsolatingInterval(const AC, AK, AH: Cardinal; constref ABound: TBigInt): TIsolatingInterval;
+class function TPolynomialRoots.CreateIsolatingInterval(const AC, AK, AH: Cardinal; constref ABound: TBigInt):
+  TIsolatingInterval;
 begin
   Result.C := AC;
   Result.K := AK;
@@ -86,17 +88,18 @@ begin
   Result.B := ((AC + AH) * ABound) >> AK;
 end;
 
-function TRootIsolation.Bisect(constref APolynomial: TBigIntPolynomial): TIsolatingIntervals;
+class function TPolynomialRoots.BisectIsolation(constref APolynomial: TBigIntPolynomial): TIsolatingIntervals;
 var
   bound: TBigInt;
 begin
-  bound := CalcSimpleRootBound(APolynomial);
-  Result := Bisect(APolynomial, bound);
+  bound := CalcUpperRootBound(APolynomial);
+  Result := BisectIsolation(APolynomial, bound);
 end;
 
 // This is adapted from
 // https://en.wikipedia.org/wiki/Real-root_isolation#Bisection_method
-function TRootIsolation.Bisect(constref APolynomial: TBigIntPolynomial; constref ABound: TBigInt): TIsolatingIntervals;
+class function TPolynomialRoots.BisectIsolation(constref APolynomial: TBigIntPolynomial; constref ABound: TBigInt):
+  TIsolatingIntervals;
 type
   TWorkItem = record
     C, K: Cardinal;
@@ -126,7 +129,7 @@ begin
       // Found an integer root at 0.
       item.P := item.P.DivideByVariable;
       Dec(n);
-      Result.Add(GetIsolatingInterval(item.C, item.K, 0, ABound));
+      Result.Add(CreateIsolatingInterval(item.C, item.K, 0, ABound));
     end;
 
     varq := item.P.RevertOrderOfCoefficients.TranslateVariableByOne;
@@ -134,7 +137,7 @@ begin
     if v = 1 then
     begin
       // Found isolating interval.
-      Result.Add(GetIsolatingInterval(item.C, item.K, 1, ABound));
+      Result.Add(CreateIsolatingInterval(item.C, item.K, 1, ABound));
     end
     else if v > 1 then
     begin
diff --git a/tests/UPolynomialRootsTestCases.pas b/tests/UPolynomialRootsTestCases.pas
index e1d765d..03faa50 100644
--- a/tests/UPolynomialRootsTestCases.pas
+++ b/tests/UPolynomialRootsTestCases.pas
@@ -32,10 +32,6 @@ type
   private
     procedure AssertBisectResult(constref AIsolatingIntervals: TIsolatingIntervals; constref AExpectedRoots:
       array of Cardinal);
-  protected
-    FRootIsolation: TRootIsolation;
-    procedure SetUp; override;
-    procedure TearDown; override;
   published
     procedure TestBisectNoBound;
     procedure TestBisectWithBound;
@@ -68,18 +64,6 @@ begin
   end;
 end;
 
-procedure TPolynomialRootsTestCase.SetUp;
-begin
-  inherited SetUp;
-  FRootIsolation := TRootIsolation.Create;
-end;
-
-procedure TPolynomialRootsTestCase.TearDown;
-begin
-  FRootIsolation.Free;
-  inherited TearDown;
-end;
-
 procedure TPolynomialRootsTestCase.TestBisectNoBound;
 const
   expRoots: array of Cardinal = (34000, 23017, 5);
@@ -90,7 +74,7 @@ begin
   // y = 3 * (x - 34000) * (x - 23017) * (x - 5) * (x^2 - 19) * (x + 112)
   //   = 3 * x^6 - 170730 * x^5 + 2329429920 * x^4 + 251300082690 * x^3 - 1270471872603 * x^2 + 4774763204640 * x - 24979889760000
   a := TBigIntPolynomial.Create([-24979889760000, 4774763204640, -1270471872603, 251300082690, 2329429920, -170730, 3]);
-  r := FRootIsolation.Bisect(a);
+  r := TPolynomialRoots.BisectIsolation(a);
   AssertBisectResult(r, expRoots);
   r.Free;
 end;
@@ -105,7 +89,7 @@ begin
   // y = 3 * (x - 34000) * (x - 23017) * (x - 5) * (x^2 - 19) * (x + 112)
   //   = 3 * x^6 - 170730 * x^5 + 2329429920 * x^4 + 251300082690 * x^3 - 1270471872603 * x^2 + 4774763204640 * x - 24979889760000
   a := TBigIntPolynomial.Create([-24979889760000, 4774763204640, -1270471872603, 251300082690, 2329429920, -170730, 3]);
-  r := FRootIsolation.Bisect(a, TBigInt.One << 15);
+  r := TPolynomialRoots.BisectIsolation(a, TBigInt.One << 15);
   AssertBisectResult(r, expRoots);
   r.Free;
 end;