**ags@pucc-i (Seaman)** (02/20/84)

No one mentioned this during the recent discussion of i**i, but I think I have found the reason that a number of people insisted that the principle value of the logarithm is the one with imaginary part in (-PI,PI]. It's defined that way in X3.9-1978 (the FORTRAN standard). That definition is just as good as any other, but it is not a universally accepted one. It seems that FORTRANers are only interested in getting an answer, not in understanding the problem. Consider complex exponentiation for example. There are infinitely many values to choose from, but somehow FORTRAN manages to compute a unique value. In order to do this, you have to give up such things as continuity. I recall the time an irate user demanded to know why his program kept bombing every time it tried to compute A**B, where A and B were real and A happened to be negative. When I asked him what sort of answer he hoped to get in that situation, he said he didn't know. He just wanted an answer so his program would run. -- Dave Seaman ..!pur-ee!pucc-i:ags "Against people who give vent to their loquacity by extraneous bombastic circumlocution."