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Added log10 to DerivativeStructure and DSCompiler. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1374162 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2012-08-17 07:15:28 +00:00
parent d48f623281
commit 64a7948cee
3 changed files with 70 additions and 2 deletions
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32
src/main/java/org/apache/commons/math3/analysis/differentiation/DSCompiler.java
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@ -1023,11 +1023,11 @@ public class DSCompiler {
}
/** Computes of a derivative structure.
/** Computes shifted logarithm of a derivative structure.
* @param operand array holding the operand
* @param operandOffset offset of the operand in its array
* @param result array where result must be stored (for
* logarithm the result array <em>cannot</em> be the input
* shifted logarithm the result array <em>cannot</em> be the input
* array)
*/
public void log1p(final double[] operand, final int operandOffset,
@ -1051,6 +1051,34 @@ public class DSCompiler {
}
/** Computes base 10 logarithm of a derivative structure.
* @param operand array holding the operand
* @param operandOffset offset of the operand in its array
* @param result array where result must be stored (for
* base 10 logarithm the result array <em>cannot</em> be the input
* array)
*/
public void log10(final double[] operand, final int operandOffset,
final double[] result, final int resultOffset) {
// create the function value and derivatives
double[] function = new double[1 + order];
function[0] = FastMath.log10(operand[operandOffset]);
if (order > 0) {
double inv = 1.0 / operand[operandOffset];
double xk = inv / FastMath.log(10.0);
for (int i = 1; i <= order; ++i) {
function[i] = xk;
xk *= -i * inv;
}
}
// apply function composition
compose(operand, operandOffset, function, result, resultOffset);
}
/** Compute cosine of a derivative structure.
* @param operand array holding the operand
* @param operandOffset offset of the operand in its array

9
src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java
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@ -636,6 +636,15 @@ public class DerivativeStructure implements FieldElement<DerivativeStructure>, S
return result;
}
/** Base 10 logarithm.
* @return base 10 logarithm of the instance
*/
public DerivativeStructure log10() {
final DerivativeStructure result = new DerivativeStructure(compiler);
compiler.log10(data, 0, result.data, 0);
return result;
}
/** Cosine operation.
* @return cos(this)
*/

31
src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java
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@ -502,6 +502,22 @@ public class DerivativeStructureTest {
}
}
@Test
public void testLog10Definition() {
double[] epsilon = new double[] { 3.0e-16, 3.0e-16, 8.0e-15, 3.0e-13, 8.0e-12 };
for (int maxOrder = 0; maxOrder < 5; ++maxOrder) {
for (double x = 0.1; x < 1.2; x += 0.001) {
DerivativeStructure dsX = new DerivativeStructure(1, maxOrder, 0, x);
DerivativeStructure log101 = dsX.log10();
DerivativeStructure log102 = dsX.log().divide(FastMath.log(10.0));
DerivativeStructure zero = log101.subtract(log102);
for (int n = 0; n <= maxOrder; ++n) {
Assert.assertEquals(0, zero.getPartialDerivative(n), epsilon[n]);
}
}
}
}
@Test
public void testLogExp() {
double[] epsilon = new double[] { 2.0e-16, 2.0e-16, 3.0e-16, 2.0e-15, 6.0e-15 };
@ -532,6 +548,21 @@ public class DerivativeStructureTest {
}
}
@Test
public void testLog10Power() {
double[] epsilon = new double[] { 3.0e-16, 3.0e-16, 9.0e-16, 6.0e-15, 6.0e-14 };
for (int maxOrder = 0; maxOrder < 5; ++maxOrder) {
for (double x = 0.1; x < 1.2; x += 0.001) {
DerivativeStructure dsX = new DerivativeStructure(1, maxOrder, 0, x);
DerivativeStructure rebuiltX = new DerivativeStructure(1, maxOrder, 10.0).pow(dsX).log10();
DerivativeStructure zero = rebuiltX.subtract(dsX);
for (int n = 0; n <= maxOrder; ++n) {
Assert.assertEquals(0, zero.getPartialDerivative(n), epsilon[n]);
}
}
}
}
@Test
public void testSinCos() {
double epsilon = 5.0e-16;