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Posted to issues@commons.apache.org by "Christian Semrau (JIRA)" <ji...@apache.org> on 2010/12/07 00:16:25 UTC
[jira] Created: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
-----------------------------------------------------------------------------------------
Key: LANG-663
URL: https://issues.apache.org/jira/browse/LANG-663
Project: Commons Lang
Issue Type: Bug
Components: lang.math.*
Affects Versions: 3.0
Reporter: Christian Semrau
Priority: Minor
The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
{code:title=FunctionTest.java|borderStyle=solid}
public void testMultiply() {
// ...
f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
f2 = Fraction.getFraction(42, 1);
f = f1.multiplyBy(f2);
assertEquals(42, f.getNumerator());
assertEquals(1, f.getDenominator());
public void testDivide() {
// ...
f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
f2 = Fraction.getFraction(42, 1);
f = f1.divideBy(f2);
assertEquals(1, f.getNumerator());
assertEquals(42, f.getDenominator());
{code}
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Christian Semrau (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12968480#action_12968480 ]
Christian Semrau commented on LANG-663:
---------------------------------------
Even if both arguments are reduced, if the divisor has numerator Integer.MIN_VALUE, divideBy may fail despite the quotient being representable with positive denominator.
{code:title=FractionTest.java|borderStyle=solid}
public void testDivide() {
// ...
f1 = Fraction.getFraction(2, 3);
f2 = Fraction.getFraction(Integer.MIN_VALUE, 3);
f = f1.divideBy(f2);
assertEquals(-1, f.getNumerator());
assertEquals(-Integer.MIN_VALUE / 2, f.getDenominator());
{code}
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
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[jira] Closed: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Henri Yandell (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Henri Yandell closed LANG-663.
------------------------------
Resolution: Fixed
svn ci -m "Adding note that this has overflow issues and pointing to BigFraction" src/main/java/org/apache/commons/lang3/math/Fraction.java
Sending src/main/java/org/apache/commons/lang3/math/Fraction.java
Transmitting file data .
Committed revision 1059747.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
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[jira] Updated: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Henri Yandell (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Henri Yandell updated LANG-663:
-------------------------------
Fix Version/s: 3.0
Need to resolve before 3.0 release.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Henri Yandell (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12981317#action_12981317 ]
Henri Yandell commented on LANG-663:
------------------------------------
Resolution sounds like it'll be pointing to Math BigFraction in the javadoc of Lang Fraction.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Christian Semrau (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976662#action_12976662 ]
Christian Semrau commented on LANG-663:
---------------------------------------
I favor having only one Fraction class, preferably in Math.
In MATH-251, the solution to overflow is using a larger number range (BigInteger). This issue (LANG-663) and LANG-662 mention spurious overflows that need not occur when using int: The overflows mentioned here can be avoided. Of course, there are many overflows that cannot be avoided, and therefore BigFraction was a valueable addition.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Stephen Colebourne (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976866#action_12976866 ]
Stephen Colebourne commented on LANG-663:
-----------------------------------------
Commons Math is a specialist library, Lang is a general purpose one. Fraction is definitely a general purpose concept, and so shoudl remain in Lang. Of course any bugs should be fixed, but remembering the general-purpose, rather than mathematical, focus.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Sebb (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976883#action_12976883 ]
Sebb commented on LANG-663:
---------------------------
I agree - Lang needs to keep its existing basic mathematical (mainly arithmetical) classes.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Christian Semrau (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12968478#action_12968478 ]
Christian Semrau commented on LANG-663:
---------------------------------------
These methods fail to reduce their arguments. This may be due to the commons-math Fraction (which seems to be the source) is always in reduced form. But commons-lang Fraction is not always reduced, and so multiplyBy must reduce its arguments, before cross-reducing the two arguments.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
--
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[jira] Commented: (LANG-663) org.apache.commons.lang3.math.Fraction
does not always succeed in multiplyBy and divideBy
Posted by "Christian Semrau (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976735#action_12976735 ]
Christian Semrau commented on LANG-663:
---------------------------------------
Oh, and seeing that method Fraction.addSub (both in Lang and Math) does all it can to ensure that spurious overflow is prevented (by using a BigInteger for an intermediate value), I wonder if the overflow of 2 / 3 divided by MIN_VALUE / 3 would be acceptable (in the Math version!), when it can be prevented too.
> org.apache.commons.lang3.math.Fraction does not always succeed in multiplyBy and divideBy
> -----------------------------------------------------------------------------------------
>
> Key: LANG-663
> URL: https://issues.apache.org/jira/browse/LANG-663
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.math.*
> Affects Versions: 3.0
> Reporter: Christian Semrau
> Priority: Minor
> Fix For: 3.0
>
>
> The Fraction.multiplyBy and divideBy methods fail sometimes when the arguments are not reduced.
> {code:title=FunctionTest.java|borderStyle=solid}
> public void testMultiply() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.multiplyBy(f2);
> assertEquals(42, f.getNumerator());
> assertEquals(1, f.getDenominator());
> public void testDivide() {
> // ...
> f1 = Fraction.getFraction(Integer.MAX_VALUE, Integer.MAX_VALUE);
> f2 = Fraction.getFraction(42, 1);
> f = f1.divideBy(f2);
> assertEquals(1, f.getNumerator());
> assertEquals(42, f.getDenominator());
> {code}
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