Values less than or equal to zero not allowed on log axis

[joelwyland]

Hi all,

I'm making an XY scatter plot with log axes for X and Y. I'm getting:

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java.lang.RuntimeException: Values less than or equal to zero not allowed with logarithmic axis
        at org.jfree.chart.axis.LogarithmicAxis.autoAdjustRange(LogarithmicAxis.java:422)......

I've printed out all of my data points and none of them are zero or negative, I'm totally confused.

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------ VALUES ------
        (0.0016578744555898748, 0.12896105027738244)
        (0.026944376865505704, 0.11966656016730082)
        (0.009001540424901745, 0.07203229835313253)
        (0.018147379404992798, 0.0557669406604897)
        (4.783178517788641E-5, 0.011618112637602021)
        (1.5325012873010813E-4, 0.011618112637602021)
        (1.7393119282012036E-4, 0.005809056318801011)

Some of them are VERY small... but none of them are zero or non-zero. What's happening?

Any help is appreciated, thanks,
Kenny

[joelwyland]

I determined what the problem was. I was using an XYSeriesCollection, which implements the IntervalXYDataset interface. When determining the "minimum" value in the dataset, the XYSeriesCollection would report the minimum value lower than what it really was, because it was including area around the value. So, my values that were really close to zero ended up reporting values below zero because the XYSeriesCollection was including some area around the actual value.

My solution was to just create my own XYDataset.... which actually kind of bugs me. Why isn't there just a simple XYDataset that keeps a bunch of XYDataItems? We have a ton of fancy datasets that I'm sure are good for really complex things, but what about just a collection of x,y points?

[david.gilbert]

I determined what the problem was. I was using an XYSeriesCollection, which implements the IntervalXYDataset interface. When determining the "minimum" value in the dataset, the XYSeriesCollection would report the minimum value lower than what it really was, because it was including area around the value. So, my values that were really close to zero ended up reporting values below zero because the XYSeriesCollection was including some area around the actual value.

That is an unintended side effect of recent changes. As a workaround, try calling setIntervalWidth(0.0) for your dataset - I think it should work, but I haven't tried it.

My solution was to just create my own XYDataset.... which actually kind of bugs me. Why isn't there just a simple XYDataset that keeps a bunch of XYDataItems? We have a ton of fancy datasets that I'm sure are good for really complex things, but what about just a collection of x,y points?

It bugs me too. XYSeriesCollection should be relatively straightforward - I will take a look at it and see if I can separate out the IntervalXYDataset implementation into a subclass (or a wrapper class) and leave XYSeriesCollection as a simple XYDataset implementation.

[Guest]

It bugs me too. XYSeriesCollection should be relatively straightforward - I will take a look at it and see if I can separate out the IntervalXYDataset implementation into a subclass (or a wrapper class) and leave XYSeriesCollection as a simple XYDataset implementation.

Thanks, that would rock.