pi=: _1&p: + 1&p:
----- Original Message ----- From: Roger Hui <[EMAIL PROTECTED]> Date: Saturday, April 5, 2008 20:14 Subject: Re: [Jgeneral] How readable is J? To: General forum <[email protected]> > You may like 2!1+m instead of 2%~m*1+m . > I also found a neater expression for the pi function: > pi=: p:^:_1 + 1&p: > > > > ----- Original Message ----- > From: John Randall <[EMAIL PROTECTED]> > Date: Saturday, April 5, 2008 18:09 > Subject: Re: [Jgeneral] How readable is J? > To: General forum <[email protected]> > > > Roger Hui wrote: > > > Something is still amiss in the formula. For > > > [[latex($$\sum_{p\in P} \left(\pi(n/p)- > > \pi(p)\right)=\sum_{p\in P} > > > \pi(n/p)- \frac{m(m-1)}2$$)]] > > > to be true, it must be that > > > [[latex($$\sum_{p\in P}\pi(p)=\frac{m(m-1)}2$$)]] > > > But: > > > > > > pi=: p:^:_1@(+ 1&p:) > > > ] p=: p: i.m=: 5 > > > 2 3 5 7 11 > > > pi p > > > 1 2 3 4 5 > > > +/ pi p > > > 15 > > > 2 %~ m*m-1 > > > 10 > > > > I think I was seduced by +/ @ i. @ # . It should be 2 %~ > > m*m+1 . ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
