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Added method multiply(int) to FieldElement, and updated implementing classes and tests accordingly. Solves MATH-684. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1178715 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Sebastien Brisard 2011-10-04 08:12:05 +00:00
parent 2898bc6403
commit 309dd689eb
5 changed files with 51 additions and 11 deletions
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10
src/main/java/org/apache/commons/math/FieldElement.java
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@ -38,6 +38,16 @@ public interface FieldElement<T> {
*/
T subtract(T a);
/** Compute n &times; this. Multiplication by an integer number is defined
* as the following sum
* <center>
* n &times; this = &sum;<sub>i=1</sub><sup>n</sup> this.
* </center>
* @param n Number of times {@code this} must be added to itself.
* @return A new element representing n &times; this.
*/
T multiply(int n);
/** Compute this &times; a.
* @param a element to multiply
* @return a new element representing this &times; a

19
src/main/java/org/apache/commons/math/complex/Complex.java
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@ -424,6 +424,25 @@ public class Complex implements FieldElement<Complex>, Serializable {
real * factor.imaginary + imaginary * factor.real);
}
/**
* Returns a {@code Complex} whose value is {@code this * factor}, with {@code factor}
* interpreted as a integer number.
*
* @param factor value to be multiplied by this {@code Complex}.
* @return {@code this * factor}.
* @see #multiply(Complex)
*/
public Complex multiply(final int factor) {
if (isNaN) {
return NaN;
}
if (Double.isInfinite(real) ||
Double.isInfinite(imaginary)) {
return INF;
}
return createComplex(real * factor, imaginary * factor);
}
/**
* Returns a {@code Complex} whose value is {@code this * factor}, with {@code factor}
* interpreted as a real number.

6
src/main/java/org/apache/commons/math/util/BigReal.java
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@ -246,6 +246,11 @@ public class BigReal implements FieldElement<BigReal>, Comparable<BigReal>, Seri
return new BigReal(d.multiply(a.d));
}
/** {@inheritDoc} */
public BigReal multiply(final int n) {
return new BigReal(d.multiply(new BigDecimal(n)));
}
/** {@inheritDoc} */
public int compareTo(BigReal a) {
return d.compareTo(a.d);
@ -288,5 +293,4 @@ public class BigReal implements FieldElement<BigReal>, Comparable<BigReal>, Seri
public Field<BigReal> getField() {
return BigRealField.getInstance();
}
}

25
src/test/java/org/apache/commons/math/complex/ComplexTest.java
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@ -129,7 +129,7 @@ public class ComplexTest {
Assert.assertTrue(Double.isNaN(x.add(z).getReal()));
}
@Test
public void testScalarAdd() {
Complex x = new Complex(3.0, 4.0);
@ -150,7 +150,7 @@ public class ComplexTest {
public void testScalarAddInf() {
Complex x = new Complex(1, 1);
double yDouble = Double.POSITIVE_INFINITY;
Complex yComplex = new Complex(yDouble);
Assert.assertEquals(x.add(yComplex), x.add(yDouble));
@ -288,11 +288,11 @@ public class ComplexTest {
yDouble = Double.NEGATIVE_INFINITY;
yComplex = new Complex(yDouble);
TestUtils.assertEquals(x.divide(yComplex), x.divide(yDouble), 0);
x = new Complex(1, Double.NEGATIVE_INFINITY);
TestUtils.assertEquals(x.divide(yComplex), x.divide(yDouble), 0);
}
@Test
public void testScalarDivideZero() {
Complex x = new Complex(1,1);
@ -313,10 +313,12 @@ public class ComplexTest {
Complex x = new Complex(3.0, 4.0);
Complex z = x.multiply(Complex.NaN);
Assert.assertSame(Complex.NaN, z);
z = Complex.NaN.multiply(5);
Assert.assertSame(Complex.NaN, z);
}
@Test
public void testMultiplyInInf() {
public void testMultiplyInfInf() {
// Assert.assertTrue(infInf.multiply(infInf).isNaN()); // MATH-620
Assert.assertTrue(infInf.multiply(infInf).isInfinite());
}
@ -340,7 +342,7 @@ public class ComplexTest {
w = negInfNegInf.multiply(oneNaN);
Assert.assertTrue(Double.isNaN(w.getReal()));
Assert.assertTrue(Double.isNaN(w.getImaginary()));
z = new Complex(1, neginf);
Assert.assertSame(Complex.INF, z.multiply(z));
}
@ -351,6 +353,9 @@ public class ComplexTest {
double yDouble = 2.0;
Complex yComplex = new Complex(yDouble);
Assert.assertEquals(x.multiply(yComplex), x.multiply(yDouble));
int zInt = -5;
Complex zComplex = new Complex(zInt);
Assert.assertEquals(x.multiply(zComplex), x.multiply(zInt));
}
@Test
@ -367,7 +372,7 @@ public class ComplexTest {
double yDouble = Double.POSITIVE_INFINITY;
Complex yComplex = new Complex(yDouble);
Assert.assertEquals(x.multiply(yComplex), x.multiply(yDouble));
yDouble = Double.NEGATIVE_INFINITY;
yComplex = new Complex(yDouble);
Assert.assertEquals(x.multiply(yComplex), x.multiply(yDouble));
@ -417,7 +422,7 @@ public class ComplexTest {
x = new Complex(neginf, 0);
Assert.assertTrue(Double.isNaN(x.subtract(z).getReal()));
}
@Test
public void testScalarSubtract() {
Complex x = new Complex(3.0, 4.0);
@ -445,7 +450,7 @@ public class ComplexTest {
Assert.assertEquals(x.subtract(yComplex), x.subtract(yDouble));
}
@Test
public void testEqualsNull() {
Complex x = new Complex(3.0, 4.0);
@ -507,7 +512,7 @@ public class ComplexTest {
Assert.assertEquals(realNaN.hashCode(), imaginaryNaN.hashCode());
Assert.assertEquals(imaginaryNaN.hashCode(), Complex.NaN.hashCode());
}
@Test
public void testAcos() {
Complex z = new Complex(3, 4);

2
src/test/java/org/apache/commons/math/util/BigRealTest.java
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@ -87,6 +87,8 @@ public class BigRealTest {
BigReal a = new BigReal("1024.0");
BigReal b = new BigReal("0.0009765625");
Assert.assertEquals(1.0, a.multiply(b).doubleValue(), 1.0e-15);
int n = 1024;
Assert.assertEquals(1.0, b.multiply(n).doubleValue(), 1.0e-15);
}
@Test