clean up PrincipalComponents

- new message "mindet"
  "Input matrix contains an indeterminate entry."

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java

@@ -4745,8 +4745,8 @@ private static IExpr powerExpandLogRational(IRational rationalNumber) {
 
     for (int i = startPosition; i < factors.size(); i++) {
       pair = (IAST) factors.get(i);
-      IExpr exponent = pair.exponent();
-      IExpr base = pair.base();
+      IExpr base = pair.arg1();
+      IExpr exponent = pair.arg2();
       if (exponent.isOne()) {
         logIntExpanded.append(F.Log(base));
       } else {

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/StatisticsFunctions.java

@@ -5382,30 +5382,36 @@ private static final class PrincipalComponents extends AbstractFunctionOptionEva
     public IExpr evaluate(final IAST ast, final int argSize, final IExpr[] option,
         final EvalEngine engine, IAST originalAST) {
       int[] dimension = ast.arg1().isMatrix();
-      RealMatrix matrix = ast.arg1().toRealMatrix();
-      if (dimension != null) {
-        if (dimension[0] == 1) {
-          if (dimension[1] == 0) {
-            return F.CEmptyList;
-          } else {
-            return F.List(F.constantArray(F.CD0, dimension[1]));
-          }
-        }
-        if (dimension[0] > 1 && dimension[1] > 0) {
-          PCA pca = null;
-          String method = option[0].toString();
-          if (method.equals("Covariance")) {
-            pca = new PCA(dimension[1]);
-          } else if (method.equals("Correlation")) {
-            pca = new PCA(dimension[1], true, true);
-          } else {
-            pca = new PCA(dimension[1]);
-          }
-          double[][] data = pca.fitAndTransform(matrix.getData());
-          return Convert.matrix2List(new Array2DRowRealMatrix(data));
+      if (dimension == null) {
+        return F.NIL;
+      }
+      if (dimension[0] == 1) {
+        if (dimension[1] == 0) {
+          return F.CEmptyList;
         }
+        return F.List(F.constantArray(F.CD0, dimension[1]));
       }
-      return F.NIL;
+
+      if (dimension[0] < 1 || dimension[1] <= 0) {
+        return F.NIL;
+      }
+
+      RealMatrix matrix = ast.arg1().toRealMatrix();
+      if (matrix == null) {
+        return F.NIL;
+      }
+
+      PCA pca = null;
+      String method = option[0].toString();
+      if (method.equals("Covariance")) {
+        pca = new PCA(dimension[1]);
+      } else if (method.equals("Correlation")) {
+        pca = new PCA(dimension[1], true, true);
+      } else {
+        pca = new PCA(dimension[1]);
+      }
+      double[][] data = pca.fitAndTransform(matrix.getData());
+      return Convert.matrix2List(new Array2DRowRealMatrix(data));
     }
 
     @Override
@@ -6248,8 +6254,7 @@ public IExpr evaluate(final IAST ast, EvalEngine engine) {
                 if (vector.exists(x -> x.isReal() && !((IReal) x).isRange(F.C0, F.C1))) {
                   // The Quantile specification `1` should be a number or a list of numbers between
                   // `2` and `3`.
-                  return Errors.printMessage(ast.topHead(), "nquan", F.list(q, F.C0, F.C1),
-                      engine);
+                  return Errors.printMessage(ast.topHead(), "nquan", F.list(q, F.C0, F.C1), engine);
                 }
                 return vector.mapThread(ast, 2);
               } else {
@@ -7005,8 +7010,7 @@ public IExpr evaluate(final IAST ast, EvalEngine engine) {
                   // numbers with length greater than the dimension of the array or two such arrays
                   // with
                   // of equal dimension.
-                  return Errors.printMessage(ast.topHead(), "rctndm1", F.list(arg1, F.C1),
-                      engine);
+                  return Errors.printMessage(ast.topHead(), "rctndm1", F.list(arg1, F.C1), engine);
                 }
                 org.hipparchus.stat.inference.TTest tTest =
                     new org.hipparchus.stat.inference.TTest();

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/Errors.java

@@ -190,6 +190,7 @@ public static void initGeneralMessages() {
       "memlimit",
       "This computation has exceeded the memeory limit settings of this evaluation engines instance.", //
       "meprec", "Internal precision limit `1` reached while evaluating `2`.", //
+      "mindet", "Input matrix contains an indeterminate entry.", //
       "minv", "The `1` arguments to `2` must be ordinary integers.", // or gaussian
       "mseqs",
       "Sequence specification or a list of sequence specifications expected at position `1` in `2`.", //
@@ -422,8 +423,7 @@ public static IExpr printMessage(ISymbol symbol, final MathException mex, EvalEn
    * @param engine
    * @return
    */
-  public static IExpr printMessage(ISymbol symbol, final Throwable exception,
-      EvalEngine engine) {
+  public static IExpr printMessage(ISymbol symbol, final Throwable exception, EvalEngine engine) {
     if (Config.SHOW_STACKTRACE) {
       exception.printStackTrace();
     }

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/data/SparseArrayExpr.java

@@ -2041,6 +2041,7 @@ public FieldVector<IExpr> toFieldVector(boolean copyArray) {
   @Override
   public RealMatrix toRealMatrix() {
     if (fDimension.length == 2 && fDimension[0] > 0 && fDimension[1] > 0) {
+      IExpr value = null;
       try {
         OpenMapRealMatrix result = new OpenMapRealMatrix(fDimension[0], fDimension[1]);
         if (!fDefaultValue.isZero()) {
@@ -2053,12 +2054,16 @@ public RealMatrix toRealMatrix() {
         }
         for (TrieNode<int[], IExpr> entry : fData.nodeSet()) {
           int[] key = entry.getKey();
-          IExpr value = entry.getValue();
+          value = entry.getValue();
           result.setEntry(key[0] - 1, key[1] - 1, value.evalf());
         }
         return result;
       } catch (ArgumentTypeException rex) {
-
+        if (value != null && value.isIndeterminate()) {
+          // Input matrix contains an indeterminate entry.
+          Errors.printMessage(S.SparseArray, "mindet", F.List());
+          return null;
+        }
       }
     }
     return null;

symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LowercaseTestCase.java

@@ -19129,6 +19129,10 @@ public void testPrimePi() {
   }
 
   public void testPrincipleComponents() {
+    // message SparseArray: Input matrix contains an indeterminate entry.
+    check(
+        "PrincipalComponents(SparseArray({{0,0},{0,0}},0) ^ (I*1/3*Pi))", //
+        "PrincipalComponents(SparseArray(Number of elements: 4 Dimensions: {2,2} Default value: 0))");
     check("PrincipalComponents({{0.25,0.33,0.45,0.01}},Method->\"Correlation\")", //
         "{{0.0,0.0,0.0,0.0}}");
     check("PrincipalComponents({{0.25,0.33,0.01}} )", //