Improve CoefficientList for SeriesData arguments

axkr · Nov 4, 2024 · 8e47671 · 8e47671
1 parent 58235e2
commit 8e47671
Show file tree

Hide file tree

Showing 4 changed files with 45 additions and 4 deletions.
diff --git a/symja_android_library/doc/functions/CoefficientList.md b/symja_android_library/doc/functions/CoefficientList.md
@@ -21,6 +21,12 @@ See:
 
 >> CoefficientList(a+c*x^2, x)
 {a,0,c}
+
+>> CoefficientList((x + y)^3, z)
+{(x+y)^3}
+        
+>> CoefficientList(Series(2*x, {x, 0, 9}), x)
+{0,2}
 ```
 
 In the next line `Coefficient` returns the coefficient of a particular term of a polynomial. In this case `(-210*c^2 * x^2*y*z^2)` is a term of `(c*x-2*y+z)^7` after it's expanded.

diff --git a/...rary/matheclipse-core/src/main/java/org/matheclipse/core/builtin/PolynomialFunctions.java b/...rary/matheclipse-core/src/main/java/org/matheclipse/core/builtin/PolynomialFunctions.java
@@ -8,7 +8,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.matheclipse.core.basic.Config;
-import org.matheclipse.core.basic.OperationSystem;
 import org.matheclipse.core.convert.JASConvert;
 import org.matheclipse.core.convert.JASIExpr;
 import org.matheclipse.core.convert.JASModInteger;
@@ -303,8 +302,13 @@ public IExpr evaluate(final IAST ast, EvalEngine engine) {
       if (ast.arg1().isList()) {
         return arg1.mapThread(ast, 1);
       }
-      IExpr expr = F.evalExpandAll(arg1, engine).normal(false);
       IAST list = ast.arg2().makeList();
+      IExpr expr = arg1.normal(false);
+      if (expr.isAST() && !expr.isFree(x -> list.indexOf(x) > 0, true)) {
+        expr = F.evalExpandAll(arg1, engine);
+      }
+      expr = engine.evaluate(expr.normal(false));
+
       return coefficientList(expr, list);
     }
 
@@ -1684,7 +1688,7 @@ private static IAST computeGroebnerBasis(IAST listOfPolynomials, IAST listOfVari
           return F.NIL;
         }
         varList.add((ISymbol) listOfVariables.get(i));
-        pvars[i - 1] = ((ISymbol) listOfVariables.get(i)).toString();
+        pvars[i - 1] = listOfVariables.get(i).toString();
       }
 
       List<GenPolynomial<BigRational>> polyList =
@@ -2072,7 +2076,7 @@ public IExpr numericFunction(IAST ast, final EvalEngine engine) {
         // https://en.wikipedia.org/wiki/Laguerre_polynomials#Physicist_Scaling_Convention
         // (Gamma(l+n+1)*Hypergeometric1F1(-n,l+1,z))/(Gamma(l+1)*n!)
         INumber nNumber = n;
-        IExpr v1 = ((INumber) l).plus(F.C1);
+        IExpr v1 = l.plus(F.C1);
         return F.Times(F.Power(F.Factorial(n), F.CN1), F.Power(F.Gamma(v1), F.CN1),
             F.Gamma(F.Plus(n, v1)), F.Hypergeometric1F1(nNumber.negate(), v1, z));
 

diff --git a/...id_library/matheclipse-core/src/main/resources/doc/functions/CoefficientList.md b/...id_library/matheclipse-core/src/main/resources/doc/functions/CoefficientList.md
@@ -21,6 +21,12 @@ See:
 
 >> CoefficientList(a+c*x^2, x)
 {a,0,c}
+
+>> CoefficientList((x + y)^3, z)
+{(x+y)^3}
+        
+>> CoefficientList(Series(2*x, {x, 0, 9}), x)
+{0,2}
 ```
 
 In the next line `Coefficient` returns the coefficient of a particular term of a polynomial. In this case `(-210*c^2 * x^2*y*z^2)` is a term of `(c*x-2*y+z)^7` after it's expanded.

diff --git a/...library/matheclipse-core/src/test/java/org/matheclipse/core/system/LowercaseTestCase.java b/...library/matheclipse-core/src/test/java/org/matheclipse/core/system/LowercaseTestCase.java
@@ -2732,6 +2732,23 @@ public void testCoefficient() {
 
   @Test
   public void testCoefficientList() {
+
+    check("CoefficientList(Series(2*x, {x, 0, 9}), x)", //
+        "{0,2}");
+    check("Series(2*x, {x, 0, 9})", //
+        "2*x+O(x)^10");
+
+    check("CoefficientList((x + y)^3, z)", //
+        "{(x+y)^3}");
+    check("CoefficientList((x - 2 y + 3 z)^3, {x, y, z})", //
+        "{{{0,0,0,27},{0,0,-54,0},{0,36,0,0},{-8,0,0,0}},{{0,0,27,0},{0,-36,0,0},{12,0,0,\n" //
+            + "0},{0,0,0,0}},{{0,9,0,0},{-6,0,0,0},{0,0,0,0},{0,0,0,0}},{{1,0,0,0},{0,0,0,0},{0,\n" //
+            + "0,0,0},{0,0,0,0}}}");
+
+    check("CoefficientList(Series(Log(1-x), {x, 0, 9}),x)", //
+        "{0,-1,-1/2,-1/3,-1/4,-1/5,-1/6,-1/7,-1/8,-1/9}");
+
+
     // check("1.0 * 10.0* x^9", //
     // "10.0*x^9");
     check("Expand((1.0 + x)^10)", //
@@ -15989,6 +16006,12 @@ public void testNorm() {
 
   @Test
   public void testNormal() {
+    check("s=Series(Exp(x), {x, 0, 5})", //
+        "1+x+x^2/2+x^3/6+x^4/24+x^5/120+O(x)^6");
+    check("Normal(s)", //
+        "1+x+x^2/2+x^3/6+x^4/24+x^5/120");
+    check("Normal(Pi)", //
+        "Pi");
     check("Normal( ConditionalExpression( 1, Element(a,Reals)&&b>0&&n>0 ) + z^3 )", //
         "1+z^3");
     check("Normal( ConditionalExpression( 1, Element(a,Reals)&&b>0&&n>0 ) + z^3, ByteArray)", //
@@ -20332,6 +20355,8 @@ public void testRealDigits() {
 
     check("RealDigits(0)", //
         "{{0},1}");
+    check("RealDigits(0,20)", //
+        "{{0},1}");
     check("RealDigits(0.1, 2)", //
         "{{1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,\n" //
             + "0,1,1,0,0,1,1,0,0,1,1,0,0,1},-3}");