Commits
François Saint-Jacques authored and Wes McKinney committed 29aa9256838
ARROW-3121: [C++] Mean aggregate kernel Implements the mean (average) kernel aggregates on numeric columns. The final type is always a double. Refactored the Sum kernel implementation to share common parts, notably the consume part is identical. Only the Finalize and output type differ. Author: François Saint-Jacques <fsaintjacques@gmail.com> Closes #3708 from fsaintjacques/ARROW-3121-mean-aggregate and squashes the following commits: 0d39c1f4 <François Saint-Jacques> reformat d41db22e <François Saint-Jacques> Refactor with ternary d1191fd8 <François Saint-Jacques> Deal with NaN values in sum c448bcbc <François Saint-Jacques> Add documentation per review 79291402 <François Saint-Jacques> Implement mean aggregate 3a1a0cd8 <François Saint-Jacques> Refactor sum implementation 8bc293f1 <François Saint-Jacques> Move TypeTraits into sum-internal.h