PieChart skipping Callout labels

Question

I have a PieChart that needs a formatted label. Since some of the sectors are small I want to use Callout for those but keep the label for the others.

This concept works for basic data.

assoc = <|"a" -> 1., "b" -> 2., "c" -> 5., "d" -> 3.|>;
PieChart[If[# < 2, Callout, Labeled][#, NumberForm[#, {2, 1}]] & /@ assoc]

However, when evaluated on some other Associations the PieChart gives a FindMinimum error and does not produce the expected result. None of the Callouts appear.

assoc2 = <|"a" -> 20.1230, "b" -> 0, "c" -> 0, "d" -> 0, 
   "e" -> 18.6519, "f" -> 32.9057, "g" -> 18.2365, "h" -> 1.2884, 
   "i" -> 5.9057, "j" -> 2.8403, "k" -> 0, "l" -> 0, "m" -> 0, 
   "n" -> 1.8480, "o" -> 0|>;
PieChart[If[# < 2, Callout, Labeled][#, NumberForm[#, {2, 1}]] & /@ assoc2]

FindMinimum::eqineq: Constraints in {False} are not all equality or inequality constraints. With the exception of integer domain constraints for linear programming, domain constraints or constraints with Unequal (!=) are not supported.

Is this a bug? Any ideas how to work around this? version 11.1.0 on Win 7 Ent

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CASE: 3883154

Answer 1

The difficulty is that you have multiple zeroes right next to each other in the data set. This is causing difficulty with the positioning algorithm which uses FindMinimum. To some extent, this is pathological data, but Callout should not completely collapse under this condition:

The workaround would be to separate the zero data, or to coalesce them together.