I suppose j stores complex numbers as REAL j. IMAG . If instead j stored radius and direction these might have better meaning:
_ad59 _j_ %_ad59 |NaN error | %_j_ angle_of =: 12&o. angle_of _1 3.14159 angle_of %__ NB. reciprocal of negative _ 0 angle_of _ar1 NB. 1 seems a reasonable result |NaN error: angle_of | angle_of _j_ ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
