ERROR Independent groups t-test 0:460:438:0:368:433:446:72:1Execute failed: function values at endpoints do not have different signs, endpoints: [-1, 1], values: [�, �]

Hello
We have a table that we are getting the following error, we notice that if one column has a at least one value of zero then we get this error.

ERROR Independent groups t-test 0:460:438:0:368:433:446:72:17 Execute failed: function values at endpoints do not have different signs, endpoints: [-1, 1], values: [�, �]

Hi @malik,

Could you provide the entire error message from knime.log? This could make debugging the issue a little easier.

Best regards,
Stefan

1 Like

Hi @stelfrich
This is the knime.log

org.apache.commons.math3.exception.NoBracketingException: function values at endpoints do not have different signs, endpoints: [-1, 1], values: [�, �]
	at org.apache.commons.math3.analysis.solvers.BrentSolver.doSolve(BrentSolver.java:122)
	at org.apache.commons.math3.analysis.solvers.BaseAbstractUnivariateSolver.solve(BaseAbstractUnivariateSolver.java:195)
	at org.apache.commons.math3.analysis.solvers.BaseAbstractUnivariateSolver.solve(BaseAbstractUnivariateSolver.java:200)
	at org.apache.commons.math3.analysis.solvers.UnivariateSolverUtils.solve(UnivariateSolverUtils.java:81)
	at org.apache.commons.math3.distribution.AbstractRealDistribution.inverseCumulativeProbability(AbstractRealDistribution.java:205)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics$KnimeTTest.getEqualVariancesNotAssumedTTest(TwoSampleTTestStatistics.java:372)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics$KnimeTTest.access$2(TwoSampleTTestStatistics.java:342)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics.getTTestCells(TwoSampleTTestStatistics.java:328)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestNodeModel.getTestStatisticsTable(TwoSampleTTestNodeModel.java:225)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestNodeModel.execute(TwoSampleTTestNodeModel.java:171)
	at org.knime.core.node.NodeModel.execute(NodeModel.java:737)
	at org.knime.core.node.NodeModel.executeModel(NodeModel.java:571)
	at org.knime.core.node.Node.invokeFullyNodeModelExecute(Node.java:1236)
	at org.knime.core.node.Node.execute(Node.java:1016)
	at org.knime.core.node.workflow.NativeNodeContainer.performExecuteNode(NativeNodeContainer.java:557)
	at org.knime.core.node.exec.LocalNodeExecutionJob.mainExecute(LocalNodeExecutionJob.java:95)
	at org.knime.core.node.workflow.NodeExecutionJob.internalRun(NodeExecutionJob.java:218)
	at org.knime.core.node.workflow.NodeExecutionJob.run(NodeExecutionJob.java:124)
	at org.knime.core.util.ThreadUtils$RunnableWithContextImpl.runWithContext(ThreadUtils.java:334)
	at org.knime.core.util.ThreadUtils$RunnableWithContext.run(ThreadUtils.java:210)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at org.knime.core.util.ThreadPool$MyFuture.run(ThreadPool.java:123)
	at org.knime.core.util.ThreadPool$Worker.run(ThreadPool.java:246)
2020-07-01 21:16:50,916 : ERROR : KNIME-Worker-1382-Independent groups t-test 0:460:438:0:368:433:446:73:19 :  : Node : Independent groups t-test : 0:460:438:0:368:433:446:73:19 : Execute failed: function values at endpoints do not have different signs, endpoints: [-1, 1], values: [�, �]
org.apache.commons.math3.exception.NoBracketingException: function values at endpoints do not have different signs, endpoints: [-1, 1], values: [�, �]
	at org.apache.commons.math3.analysis.solvers.BrentSolver.doSolve(BrentSolver.java:122)
	at org.apache.commons.math3.analysis.solvers.BaseAbstractUnivariateSolver.solve(BaseAbstractUnivariateSolver.java:195)
	at org.apache.commons.math3.analysis.solvers.BaseAbstractUnivariateSolver.solve(BaseAbstractUnivariateSolver.java:200)
	at org.apache.commons.math3.analysis.solvers.UnivariateSolverUtils.solve(UnivariateSolverUtils.java:81)
	at org.apache.commons.math3.distribution.AbstractRealDistribution.inverseCumulativeProbability(AbstractRealDistribution.java:205)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics$KnimeTTest.getEqualVariancesNotAssumedTTest(TwoSampleTTestStatistics.java:372)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics$KnimeTTest.access$2(TwoSampleTTestStatistics.java:342)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestStatistics.getTTestCells(TwoSampleTTestStatistics.java:328)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestNodeModel.getTestStatisticsTable(TwoSampleTTestNodeModel.java:225)
	at org.knime.base.node.stats.testing.ttest.TwoSampleTTestNodeModel.execute(TwoSampleTTestNodeModel.java:171)
	at org.knime.core.node.NodeModel.execute(NodeModel.java:737)
	at org.knime.core.node.NodeModel.executeModel(NodeModel.java:571)
	at org.knime.core.node.Node.invokeFullyNodeModelExecute(Node.java:1236)
	at org.knime.core.node.Node.execute(Node.java:1016)
	at org.knime.core.node.workflow.NativeNodeContainer.performExecuteNode(NativeNodeContainer.java:557)
	at org.knime.core.node.exec.LocalNodeExecutionJob.mainExecute(LocalNodeExecutionJob.java:95)
	at org.knime.core.node.workflow.NodeExecutionJob.internalRun(NodeExecutionJob.java:218)
	at org.knime.core.node.workflow.NodeExecutionJob.run(NodeExecutionJob.java:124)
	at org.knime.core.util.ThreadUtils$RunnableWithContextImpl.runWithContext(ThreadUtils.java:334)
	at org.knime.core.util.ThreadUtils$RunnableWithContext.run(ThreadUtils.java:210)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at org.knime.core.util.ThreadPool$MyFuture.run(ThreadPool.java:123)
	at org.knime.core.util.ThreadPool$Worker.run(ThreadPool.java:246)

Hi @malik,

I have looked into this and was able to reproduce the error that you are describing but only under very artificial conditions: If all values in a column are zero.

In this example I wasn’t able to observe the error if only a few cells had 0.0 values (see top branch). Is it possible that one of your groups has only missing values in a column?

Best,
Stefan

2 Likes

Great now i works. We have removed every constant column.

4 Likes

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