Thank you for responding. I believe that f...@g t.i.n must be equal to (f t.i.n)&p.@(g t.i.n)&p. t.i.n for all nonnegative integer values of n . High order terms in f or g do not induce low order terms in f...@g
But I don't think that computing the noun f...@g t.i.n for a big n is efficient for implementing the verb f...@g t. The evaluation of (1&o.t.n)&p.^:2 t.n=.i.24 was slow, but I was impressed that it did work after all! --- Den man 10/5/10 skrev Roger Hui <[email protected]>: > Fra: Roger Hui <[email protected]> > Emne: Re: [Jprogramming] Taylor expansion of sin(sin(x)) > Til: "Programming forum" <[email protected]> > Dato: mandag 10. maj 2010 02.40 > 1&o.^:2 t. signals domain error > because > u t. does a table look-up and 1&o.^:2 is not > in the table. > > Are you claiming that if f t. and g t. both > work then f...@g t. should work? > > > > ----- Original Message ----- > From: Bo Jacoby <[email protected]> > Date: Sunday, May 9, 2010 3:45 > Subject: [Jprogramming] Taylor expansion of sin(sin(x)) > To: Programming forum <[email protected]> > > > 1&o.t.i.10 NB. The sine function is taylor > > expanded > > 0 1 0 _0.166667 0 0.00833333 0 _0.000198413 0 > 2.75573e_6 > > 1&o.t.i.10x NB. exactly > > 0 1 0 _1r6 0 1r120 0 _1r5040 0 1r362880 > > 1&o.^:2 t.i.10x NB. Why does sin sin x > produces an > > error message? > > |domain error > > | 1&o.^:2 t.i.10 > > (1&o.t.i.10)&p.^:2 t.i.10 NB. this trick > works around the bug > > 0 1 0 _1r3 0 1r10 0 _8r315 0 13r2520 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
