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Added "derivative". 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1185184 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Gilles Sadowski 2011-10-17 14:05:53 +00:00
parent 5aaf1adc15
commit 9227754177
1 changed files with 15 additions and 1 deletions
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16
src/main/java/org/apache/commons/math/analysis/function/Log10.java
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@ -18,6 +18,7 @@
package org.apache.commons.math.analysis.function; package org.apache.commons.math.analysis.function;
import org.apache.commons.math.analysis.UnivariateRealFunction; import org.apache.commons.math.analysis.UnivariateRealFunction;
import org.apache.commons.math.analysis.DifferentiableUnivariateRealFunction;
import org.apache.commons.math.util.FastMath; import org.apache.commons.math.util.FastMath;
/** /**
@ -26,9 +27,22 @@ import org.apache.commons.math.util.FastMath;
* @version $Id$ * @version $Id$
* @since 3.0 * @since 3.0
*/ */
public class Log10 implements UnivariateRealFunction { public class Log10 implements DifferentiableUnivariateRealFunction {
/** ln(10) = {@value}.*/
private static final double LN_10 = FastMath.log(10);
/** {@inheritDoc} */ /** {@inheritDoc} */
public double value(double x) { public double value(double x) {
return FastMath.log10(x); return FastMath.log10(x);
} }
/** {@inheritDoc} */
public UnivariateRealFunction derivative() {
return new UnivariateRealFunction() {
/** {@inheritDoc} */
public double value(double x) {
return 1 / (x * LN_10);
}
};
}
} }