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Diffstat (limited to 'src/main/java/org/apache/commons/math3/ode/nonstiff/DormandPrince54FieldStepInterpolator.java')
| -rw-r--r-- | src/main/java/org/apache/commons/math3/ode/nonstiff/DormandPrince54FieldStepInterpolator.java | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/ode/nonstiff/DormandPrince54FieldStepInterpolator.java b/src/main/java/org/apache/commons/math3/ode/nonstiff/DormandPrince54FieldStepInterpolator.java new file mode 100644 index 0000000..62a6fa3 --- /dev/null +++ b/src/main/java/org/apache/commons/math3/ode/nonstiff/DormandPrince54FieldStepInterpolator.java @@ -0,0 +1,249 @@ +/* + * 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.nonstiff; + +import org.apache.commons.math3.Field; +import org.apache.commons.math3.RealFieldElement; +import org.apache.commons.math3.ode.FieldEquationsMapper; +import org.apache.commons.math3.ode.FieldODEStateAndDerivative; + +/** + * This class represents an interpolator over the last step during an + * ODE integration for the 5(4) Dormand-Prince integrator. + * + * @see DormandPrince54Integrator + * + * @param <T> the type of the field elements + * @since 3.6 + */ + +class DormandPrince54FieldStepInterpolator<T extends RealFieldElement<T>> + extends RungeKuttaFieldStepInterpolator<T> { + + /** Last row of the Butcher-array internal weights, element 0. */ + private final T a70; + + // element 1 is zero, so it is neither stored nor used + + /** Last row of the Butcher-array internal weights, element 2. */ + private final T a72; + + /** Last row of the Butcher-array internal weights, element 3. */ + private final T a73; + + /** Last row of the Butcher-array internal weights, element 4. */ + private final T a74; + + /** Last row of the Butcher-array internal weights, element 5. */ + private final T a75; + + /** Shampine (1986) Dense output, element 0. */ + private final T d0; + + // element 1 is zero, so it is neither stored nor used + + /** Shampine (1986) Dense output, element 2. */ + private final T d2; + + /** Shampine (1986) Dense output, element 3. */ + private final T d3; + + /** Shampine (1986) Dense output, element 4. */ + private final T d4; + + /** Shampine (1986) Dense output, element 5. */ + private final T d5; + + /** Shampine (1986) Dense output, element 6. */ + private final T d6; + + /** Simple constructor. + * @param field field to which the time and state vector elements belong + * @param forward integration direction indicator + * @param yDotK slopes at the intermediate points + * @param globalPreviousState start of the global step + * @param globalCurrentState end of the global step + * @param softPreviousState start of the restricted step + * @param softCurrentState end of the restricted step + * @param mapper equations mapper for the all equations + */ + DormandPrince54FieldStepInterpolator(final Field<T> field, final boolean forward, + final T[][] yDotK, + final FieldODEStateAndDerivative<T> globalPreviousState, + final FieldODEStateAndDerivative<T> globalCurrentState, + final FieldODEStateAndDerivative<T> softPreviousState, + final FieldODEStateAndDerivative<T> softCurrentState, + final FieldEquationsMapper<T> mapper) { + super(field, forward, yDotK, + globalPreviousState, globalCurrentState, softPreviousState, softCurrentState, + mapper); + final T one = field.getOne(); + a70 = one.multiply( 35.0).divide( 384.0); + a72 = one.multiply( 500.0).divide(1113.0); + a73 = one.multiply( 125.0).divide( 192.0); + a74 = one.multiply(-2187.0).divide(6784.0); + a75 = one.multiply( 11.0).divide( 84.0); + d0 = one.multiply(-12715105075.0).divide( 11282082432.0); + d2 = one.multiply( 87487479700.0).divide( 32700410799.0); + d3 = one.multiply(-10690763975.0).divide( 1880347072.0); + d4 = one.multiply(701980252875.0).divide(199316789632.0); + d5 = one.multiply( -1453857185.0).divide( 822651844.0); + d6 = one.multiply( 69997945.0).divide( 29380423.0); + } + + /** {@inheritDoc} */ + @Override + protected DormandPrince54FieldStepInterpolator<T> create(final Field<T> newField, final boolean newForward, final T[][] newYDotK, + final FieldODEStateAndDerivative<T> newGlobalPreviousState, + final FieldODEStateAndDerivative<T> newGlobalCurrentState, + final FieldODEStateAndDerivative<T> newSoftPreviousState, + final FieldODEStateAndDerivative<T> newSoftCurrentState, + final FieldEquationsMapper<T> newMapper) { + return new DormandPrince54FieldStepInterpolator<T>(newField, newForward, newYDotK, + newGlobalPreviousState, newGlobalCurrentState, + newSoftPreviousState, newSoftCurrentState, + newMapper); + } + /** {@inheritDoc} */ + @SuppressWarnings("unchecked") + @Override + protected FieldODEStateAndDerivative<T> computeInterpolatedStateAndDerivatives(final FieldEquationsMapper<T> mapper, + final T time, final T theta, + final T thetaH, final T oneMinusThetaH) { + + // interpolate + final T one = time.getField().getOne(); + final T eta = one.subtract(theta); + final T twoTheta = theta.multiply(2); + final T dot2 = one.subtract(twoTheta); + final T dot3 = theta.multiply(theta.multiply(-3).add(2)); + final T dot4 = twoTheta.multiply(theta.multiply(twoTheta.subtract(3)).add(1)); + final T[] interpolatedState; + final T[] interpolatedDerivatives; + if (getGlobalPreviousState() != null && theta.getReal() <= 0.5) { + final T f1 = thetaH; + final T f2 = f1.multiply(eta); + final T f3 = f2.multiply(theta); + final T f4 = f3.multiply(eta); + final T coeff0 = f1.multiply(a70). + subtract(f2.multiply(a70.subtract(1))). + add(f3.multiply(a70.multiply(2).subtract(1))). + add(f4.multiply(d0)); + final T coeff1 = time.getField().getZero(); + final T coeff2 = f1.multiply(a72). + subtract(f2.multiply(a72)). + add(f3.multiply(a72.multiply(2))). + add(f4.multiply(d2)); + final T coeff3 = f1.multiply(a73). + subtract(f2.multiply(a73)). + add(f3.multiply(a73.multiply(2))). + add(f4.multiply(d3)); + final T coeff4 = f1.multiply(a74). + subtract(f2.multiply(a74)). + add(f3.multiply(a74.multiply(2))). + add(f4.multiply(d4)); + final T coeff5 = f1.multiply(a75). + subtract(f2.multiply(a75)). + add(f3.multiply(a75.multiply(2))). + add(f4.multiply(d5)); + final T coeff6 = f4.multiply(d6).subtract(f3); + final T coeffDot0 = a70. + subtract(dot2.multiply(a70.subtract(1))). + add(dot3.multiply(a70.multiply(2).subtract(1))). + add(dot4.multiply(d0)); + final T coeffDot1 = time.getField().getZero(); + final T coeffDot2 = a72. + subtract(dot2.multiply(a72)). + add(dot3.multiply(a72.multiply(2))). + add(dot4.multiply(d2)); + final T coeffDot3 = a73. + subtract(dot2.multiply(a73)). + add(dot3.multiply(a73.multiply(2))). + add(dot4.multiply(d3)); + final T coeffDot4 = a74. + subtract(dot2.multiply(a74)). + add(dot3.multiply(a74.multiply(2))). + add(dot4.multiply(d4)); + final T coeffDot5 = a75. + subtract(dot2.multiply(a75)). + add(dot3.multiply(a75.multiply(2))). + add(dot4.multiply(d5)); + final T coeffDot6 = dot4.multiply(d6).subtract(dot3); + interpolatedState = previousStateLinearCombination(coeff0, coeff1, coeff2, coeff3, + coeff4, coeff5, coeff6); + interpolatedDerivatives = derivativeLinearCombination(coeffDot0, coeffDot1, coeffDot2, coeffDot3, + coeffDot4, coeffDot5, coeffDot6); + } else { + final T f1 = oneMinusThetaH.negate(); + final T f2 = oneMinusThetaH.multiply(theta); + final T f3 = f2.multiply(theta); + final T f4 = f3.multiply(eta); + final T coeff0 = f1.multiply(a70). + subtract(f2.multiply(a70.subtract(1))). + add(f3.multiply(a70.multiply(2).subtract(1))). + add(f4.multiply(d0)); + final T coeff1 = time.getField().getZero(); + final T coeff2 = f1.multiply(a72). + subtract(f2.multiply(a72)). + add(f3.multiply(a72.multiply(2))). + add(f4.multiply(d2)); + final T coeff3 = f1.multiply(a73). + subtract(f2.multiply(a73)). + add(f3.multiply(a73.multiply(2))). + add(f4.multiply(d3)); + final T coeff4 = f1.multiply(a74). + subtract(f2.multiply(a74)). + add(f3.multiply(a74.multiply(2))). + add(f4.multiply(d4)); + final T coeff5 = f1.multiply(a75). + subtract(f2.multiply(a75)). + add(f3.multiply(a75.multiply(2))). + add(f4.multiply(d5)); + final T coeff6 = f4.multiply(d6).subtract(f3); + final T coeffDot0 = a70. + subtract(dot2.multiply(a70.subtract(1))). + add(dot3.multiply(a70.multiply(2).subtract(1))). + add(dot4.multiply(d0)); + final T coeffDot1 = time.getField().getZero(); + final T coeffDot2 = a72. + subtract(dot2.multiply(a72)). + add(dot3.multiply(a72.multiply(2))). + add(dot4.multiply(d2)); + final T coeffDot3 = a73. + subtract(dot2.multiply(a73)). + add(dot3.multiply(a73.multiply(2))). + add(dot4.multiply(d3)); + final T coeffDot4 = a74. + subtract(dot2.multiply(a74)). + add(dot3.multiply(a74.multiply(2))). + add(dot4.multiply(d4)); + final T coeffDot5 = a75. + subtract(dot2.multiply(a75)). + add(dot3.multiply(a75.multiply(2))). + add(dot4.multiply(d5)); + final T coeffDot6 = dot4.multiply(d6).subtract(dot3); + interpolatedState = currentStateLinearCombination(coeff0, coeff1, coeff2, coeff3, + coeff4, coeff5, coeff6); + interpolatedDerivatives = derivativeLinearCombination(coeffDot0, coeffDot1, coeffDot2, coeffDot3, + coeffDot4, coeffDot5, coeffDot6); + } + return new FieldODEStateAndDerivative<T>(time, interpolatedState, interpolatedDerivatives); + + } + +} |