Improve NIntegrate quadrature methos (Spotbugs findings)

axkr · Oct 25, 2024 · d4c89b7 · d4c89b7
1 parent e29ea68
commit d4c89b7
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Showing 4 changed files with 8 additions and 5 deletions.
diff --git a/...matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/ClenshawCurtis.java b/...matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/ClenshawCurtis.java
@@ -1,6 +1,7 @@
 package org.matheclipse.core.numerics.integral;
 
 import java.util.function.DoubleUnaryOperator;
+import org.matheclipse.core.expression.F;
 import org.matheclipse.core.numerics.utils.Constants;
 import org.matheclipse.core.numerics.utils.SimpleMath;
 
@@ -484,7 +485,7 @@ private static final void adapquad(final DoubleUnaryOperator f, double a, double
       if (next == 4) {
 
         // UPDATE
-        if (n != 4 || !(caution || (xa == a && div == 0))) {
+        if (n != 4 || !(caution || (F.isEqual(xa, a) && div == 0))) {
           if (e < re) {
             e = re;
           }

diff --git a/...y/matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/GaussLobatto.java b/...y/matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/GaussLobatto.java
@@ -1,6 +1,7 @@
 package org.matheclipse.core.numerics.integral;
 
 import java.util.function.DoubleUnaryOperator;
+import org.matheclipse.core.expression.F;
 import org.matheclipse.core.numerics.utils.Constants;
 
 /**
@@ -78,7 +79,7 @@ private final QuadratureResult dlob8e(final DoubleUnaryOperator f, final double
     s += Y[4] * (y5 + y9) + Y[5] * (f5 + f6) + Y[6] * y7;
     s *= h;
     double rtol = myTol;
-    if (est1 != s) {
+    if (!F.isEqual(est1, s)) {
       final double r = Math.abs(est2 - s) / Math.abs(est1 - s);
       if (r > 0.0 && r < 1.0) {
         rtol /= r;
@@ -128,7 +129,7 @@ private final double dlob8(final DoubleUnaryOperator f, final double a, final do
     est2 *= (h / 1470.0);
 
     // check the convergence
-    if (s + (est2 - est1) == s || mll <= a || b <= mrr) {
+    if (F.isZero(est2 - est1) || mll <= a || b <= mrr) {
       return est2;
     }
 

diff --git a/...ibrary/matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/Simpson.java b/...ibrary/matheclipse-core/src/main/java/org/matheclipse/core/numerics/integral/Simpson.java
@@ -5,6 +5,7 @@
 import java.util.PriorityQueue;
 import java.util.Stack;
 import java.util.function.DoubleUnaryOperator;
+import org.matheclipse.core.expression.F;
 
 /**
  * A local and global adaptive numerical integrator based on Simpson's rule [1]. For all
@@ -224,7 +225,7 @@ private final QuadratureResult localSimpson(final DoubleUnaryOperator func, fina
       final double err = Math.abs(fine - crude);
 
       // if the error is within the tolerance, update the global integral estimate
-      if (fev > 5 && (err <= 15.0 * eps || wid == 0.0 || eps * 2 == eps)) {
+      if (fev > 5 && (err <= 15.0 * eps || F.isZero(wid) || F.isZero(eps + eps, eps))) {
         est += fine + (fine - crude) / 15.0;
         continue;
       }

diff --git a/...oid_library/matheclipse-core/src/test/java/org/matheclipse/core/system/IntegrateTest.java b/...oid_library/matheclipse-core/src/test/java/org/matheclipse/core/system/IntegrateTest.java
@@ -317,7 +317,7 @@ public void testIntegrate() {
   public void testNIntegrate() {
     // avoid Indeterminate at 0
     checkNumeric("NIntegrate(1/Sqrt(x), {x, 0.001, 1}, Method -> \"GaussLobattoRule\")", //
-        "1.9367544467966367");
+        "1.9367544467966324");
     checkNumeric("NIntegrate(1/Sqrt(x), {x, 0.001, 1}, Method -> \"NewtonCotesRule\")", //
         "1.936754446797901");
     checkNumeric("NIntegrate(Sqrt(x), {x, 0, 1}, Method -> \"ClenshawCurtisRule\")", //