Function exactCorrelation

src/compute-engine/library/statistics.ts:957–987

Exact Pearson r; `null` if a variance is zero (division by zero).

(
  ce: ComputeEngine,
  xs: Expression[],
  ys: Expression[]
)

        return ce.function(
          'List',
          counts.map((count, i) =>
            ce._fn('Tuple', [ce.number(binEdges[i]), ce.number(count)])
          )
        );
      },
    },

    BinCounts: {
      description: 'Count the number of elements falling into each bin.',
      complexity: 8200,
      // Same widened bin spec as Histogram (non-integer counts stay inert).
      signature: '(collection<any>, number | list<number>) -> list<number>',
      examples: ['BinCounts([1, 2, 2, 3], 3)  // Returns [1, 2, 1]'],
      // Decline-only, same `computeBinning` precondition as `Histogram`.
      canEnumerate: canEnumerateFiniteSource,
      evaluate: ([xs, binsArg], { engine: ce }) => {
        const binning = computeBinning(xs, binsArg);
        if (!binning) return undefined;
        if (binning.rejected)
          return dataConstraintError(
            ce,
            'BinCounts',
            binning.rejected.value,
            binning.rejected.constraint
          );

        return ce.function(
          'List',
          binning.counts.map((c) => ce.number(c))
        );
      },
    },

    SlidingWindow: {