Check-in commons-math 3.6.1 am: 1354beaf45 am: 0018f64b87 am: b3715644fb am: 5484895ffd

Original change: https://android-review.googlesource.com/c/platform/external/apache-commons-math/+/2702413

Change-Id: Idb04c8014ec76e9930d6d0aa22dac3b0b54333c8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/src/main/java/org/apache/commons/math3/ode/SecondOrderIntegrator.java b/src/main/java/org/apache/commons/math3/ode/SecondOrderIntegrator.java
new file mode 100644
index 0000000..4df6c65
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+++ b/src/main/java/org/apache/commons/math3/ode/SecondOrderIntegrator.java
@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.math3.ode;
+
+import org.apache.commons.math3.exception.MathIllegalArgumentException;
+import org.apache.commons.math3.exception.MathIllegalStateException;
+
+/**
+ * This interface represents a second order integrator for differential equations.
+ *
+ * <p>The classes which are devoted to solve second order differential equations should implement
+ * this interface. The problems which can be handled should implement the {@link
+ * SecondOrderDifferentialEquations} interface.
+ *
+ * @see SecondOrderDifferentialEquations
+ * @since 1.2
+ */
+public interface SecondOrderIntegrator extends ODEIntegrator {
+
+    /**
+     * Integrate the differential equations up to the given time
+     *
+     * @param equations differential equations to integrate
+     * @param t0 initial time
+     * @param y0 initial value of the state vector at t0
+     * @param yDot0 initial value of the first derivative of the state vector at t0
+     * @param t target time for the integration (can be set to a value smaller thant <code>t0</code>
+     *     for backward integration)
+     * @param y placeholder where to put the state vector at each successful step (and hence at the
+     *     end of integration), can be the same object as y0
+     * @param yDot placeholder where to put the first derivative of the state vector at time t, can
+     *     be the same object as yDot0
+     * @throws MathIllegalStateException if the integrator cannot perform integration
+     * @throws MathIllegalArgumentException if integration parameters are wrong (typically too small
+     *     integration span)
+     */
+    void integrate(
+            SecondOrderDifferentialEquations equations,
+            double t0,
+            double[] y0,
+            double[] yDot0,
+            double t,
+            double[] y,
+            double[] yDot)
+            throws MathIllegalStateException, MathIllegalArgumentException;
+}