Attached quartic polynomial solver (tested & debugged) fails on java version "1.7.0_05-icedtea" OpenJDK Runtime Environment (fedora-2.2.1.fc17.9-x86_64) OpenJDK 64-Bit Server VM (build 23.0-b21, mixed mode) java PolynomialRoot !!!!!!!!n=4 test 787 !!!!!!!!n=4 test 788 !!!!!!!!n=4 test 789 !!!!!!!!n=4 test 790 Exception in thread "main" java.lang.RuntimeException: order=4 p[0]=0.0;p[1]=0.452284529771106;p[2]=0.54454120923573;p[3]=-0.06854826782854806;p[4]=0.6465099113690949; x.r=0.33797241959903046 x.i=0.284958330701781 res/sabs=0.02367127931554906 ims/sabs=0.037244001943407073 sabs=6.360407524751092 res=0.15055898307910312 ims=0.23688703021269064 n=4 eps=1.0E-6 sabs>1/eps=false f1=true f2=true t=790 at PolynomialRoot.checkValues(PolynomialRoot.java:424) at PolynomialRoot.testRoots(PolynomialRoot.java:491) at PolynomialRoot.main(PolynomialRoot.java:762) In the same time on java -version java version "1.6.0_0" OpenJDK Runtime Environment (IcedTea6 1.6) (fedora-23.b16.fc10-x86_64) OpenJDK 64-Bit Server VM (build 14.0-b16, mixed mode) works OK !!!!!!!!n=4 test 73631 !!!!!!!!n=4 test 73632 !!!!!!!!n=4 test 73633 !!!!!!!!n=4 test 73634 !!!!!!!!n=4 test 73635 !!!!!!!!n=4 test 73636 ..... Trying to enable println by settings PRINT_DEBUG=true make the code working, no failure occur.
Created attachment 605282 [details] The code The code. Tested on 3 different computers. with java -version java version "1.7.0_05-icedtea" OpenJDK Runtime Environment (fedora-2.2.1.fc17.9-x86_64) OpenJDK 64-Bit Server VM (build 23.0-b21, mixed mode) always give a failure above
Interesting that java -XX:LoopUnrollLimit=1 PolynomialRoot give no this error on java -version java version "1.7.0_05-icedtea" OpenJDK Runtime Environment (fedora-2.2.1.fc17.9-x86_64) OpenJDK 64-Bit Server VM (build 23.0-b21, mixed mode) java -XX:LoopUnrollLimit=1 PolynomialRoot ....... !!!!!!!!n=4 test 30977 !!!!!!!!n=4 test 30978 !!!!!!!!n=4 test 30979 !!!!!!!!n=4 test 30980 !!!!!!!!n=4 test 30981 .......
There is just a single relevant loop in attached code: int jmin=0; double vmin=Math.abs(u[jmin]); for(int j=1;j<3;j++) { final double vx=Math.abs(u[j]); if(vx<vmin) { vmin=vx; jmin=j; } } final double u1=u[(jmin+1)%3],u2=u[(jmin+2)%3];
The option java -XX:-UseLoopPredicate PolynomialRoot also make the unit test passing OK
And setting two options simultaneously java -XX:LoopUnrollLimit=1 -XX:-UseLoopPredicate PolynomialRoot give an error !!!!!!!!n=4 test 779 !!!!!!!!n=4 test 780 !!!!!!!!n=4 test 781 Exception in thread "main" java.lang.RuntimeException: order=4 p[0]=-0.3643937449673187;p[1]=0.26975356192753797;p[2]=0.469327423289146;p[3]=0.5513987308711439;p[4]=0.4989414549559419; x.r=-0.22593059759284145 x.i=0.8351448422318095 res/sabs=-0.02103905708525171 ims/sabs=0.0025556115548346493 sabs=16.016871636436743 res=-0.3369798766861416 ims=0.0409329022263811 n=4 eps=1.0E-6 sabs>1/eps=false f1=true f2=true t=781 at PolynomialRoot.checkValues(PolynomialRoot.java:424) at PolynomialRoot.testRoots(PolynomialRoot.java:491) at PolynomialRoot.main(PolynomialRoot.java:762) as well as java -XX:LoopUnrollLimit=0 -XX:-UseLoopPredicate PolynomialRoot !!!!!!!!n=4 test 809 !!!!!!!!n=4 test 810 Exception in thread "main" java.lang.RuntimeException: order=4 p[0]=-0.7203446925952928;p[1]=0.9162323551969194;p[2]=0.7020835015265718;p[3]=0.6581445844611;p[4]=0.65585375261305; x.r=-0.05428215319033669 x.i=0.9322319811155485 res/sabs=-0.04156563071819642 ims/sabs=0.0192423628643677 sabs=19.243195867204115 res=-0.7998555732541297 ims=0.3702845575468425 n=4 eps=1.0E-6 sabs>1/eps=false f1=true f2=true t=810 at PolynomialRoot.checkValues(PolynomialRoot.java:424) at PolynomialRoot.testRoots(PolynomialRoot.java:491) at PolynomialRoot.main(PolynomialRoot.java:762) but again. Single -XX:LoopUnrollLimit=1 or -XX:-UseLoopPredicate produce no error But together they do produce an error (as well as when the code is run without any option) single option produce no error
Another thing - the failure almost never occur on a computer with high load. Idle computer give a failure almost immediately.
Still the same problem in java -version java version "1.7.0_09-icedtea" OpenJDK Runtime Environment (fedora-2.3.3.fc17.1-x86_64) OpenJDK 64-Bit Server VM (build 23.2-b09, mixed mode)
Created attachment 656014 [details] Same failure on Oracle jdk same thing with Oracle JDK java -version java version "1.7.0_09" Java(TM) SE Runtime Environment (build 1.7.0_09-b05) Java HotSpot(TM) 64-Bit Server VM (build 23.5-b02, mixed mode) java PolynomialRoot ..... !!!!!!!!n=4 test 777 !!!!!!!!n=4 test 778 !!!!!!!!n=4 test 779 Exception in thread "main" java.lang.RuntimeException: order=4 p[0]=0.9757454361894038;p[1]=0.0;p[2]=-0.9063855238682716;p[3]=0.8365853061995829;p[4]=-0.48284015470752206; x.r=0.6072512814712652 x.i=0.9978109661117348 res/sabs=0.05808884723864624 ims/sabs=-0.021584173284394766 sabs=12.62240660496392 res=0.7332210490598285 ims=-0.2724442114276303 n=4 eps=1.0E-6 sabs>1/eps=false f1=true f2=true t=779 at PolynomialRoot.checkValues(PolynomialRoot.java:426) at PolynomialRoot.testRoots(PolynomialRoot.java:493) at PolynomialRoot.main(PolynomialRoot.java:764)
And disabling hotspot java -Xint PolynomialRoot Make the test passing OK
This well documented with test case provided bug some time ago was submitted to Oracle java bug database as 2396372 There is no reaction. Same thing with other bugs I submitted to Oracle. java development at Oracle is stalled and Oracle does not care about bugs. Can somebody look at fix this bug here. The test case is provided. It should not be difficult.
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