Y must be a positive numeric array. R is numeric. R is the natural (or Napierian) logarithm of Y whose base is the mathematical constant e=2.71828....
⍟1 2 0 0.6931471806 ⍟2 2⍴0j1 1j2 2j3 3j4 0.000000000J1.570796327 0.8047189562J1.107148718 1.282474679J0.9827937232 1.6094379120J0.927295218