histogram widget filter is sending wrong bounds

[javisantana]

When you filter using the last bucket in a histogram bucket the filter sends wrong bounds, for example:

the buckets goes from 400 to 500, you filter it and the filter sent to the tiler is [400, 499.9999] so rows with 500 are kept out.

how to reproduce:

• go here: http://cartodb.github.io/widgets-examples/airbnb_madrid_oct_2015_listings.html
• filter like in the image:
  
• notice the values sent in the map instanciation

[javierarce]

I'm afraid those values are calculated in the backend. The frontend picks the values from the data model using the lower and upper index.

/cc @rochoa

[rochoa]

The problem is the zoomed histogram returns with:

{
  "bin_width": 66.8333333333333,
  "bins_count": 6,
  "bins_start": 99,
  ...
}

So ... 66.8333333333333 * 6 + 99 = 499.9999999999998.

More on this:

$ node
> // https://gist.github.com/rochoa/5b57e57c9694741c4887
> // Following code was extracted from almost-equal
undefined
> // (c) 2013 Mikola Lysenko. MIT License
undefined
> // MIT License (MIT)
undefined
> // See https://github.com/scijs/almost-equal/blob/93af191fe4075ee2dea94d29a26c796c26bb9cb6/almost_equal.js
undefined
>
undefined
> var PRECISION_FLOAT_EPSILON = 1.19209290e-7;
undefined
> var PRECISION_DOUBLE_EPSILON = 2.2204460492503131e-16;
undefined
>
undefined
> function almostEqual(a, b, absoluteError, relativeError) {
...     absoluteError = absoluteError || PRECISION_DOUBLE_EPSILON;
...     relativeError = relativeError || PRECISION_DOUBLE_EPSILON;
...
...     var d = Math.abs(a - b);
...     if(d <= absoluteError) {
...         return true;
...     }
...     if(d <= relativeError * Math.min(Math.abs(a), Math.abs(b))) {
...         return true;
...     }
...
...     return a === b;
... }
undefined
> almostEqual(66.8333333333333 * 6 + 99, 500, PRECISION_FLOAT_EPSILON, PRECISION_FLOAT_EPSILON)
true

[rochoa]

Just by changing the selection to:

You get rid of the precision problem because you get:

{
  "bin_width": 52,
  "bins_count": 6,
  "bins_start": 188,
  ...
}

In this case: 52 * 6 + 188 = 500.

We might not have a good solution here if we don't want to change the way the bin width is being calculated.

[nobuti]

There has been no activity on this issue for several months and that's why we are closing it (automatically). If you think this still needs to be addressed please reopen it. The good news is that we are now working on the next version of CARTO.js, stay tuned.