Re: what's wrong with these expressions?

*To*: mathgroup at smc.vnet.net*Subject*: [mg104614] Re: [mg104606] what's wrong with these expressions?*From*: DrMajorBob <btreat1 at austin.rr.com>*Date*: Thu, 5 Nov 2009 03:47:40 -0500 (EST)*References*: <200911040641.BAA09061@smc.vnet.net>*Reply-to*: drmajorbob at yahoo.com

No problem here: {Subscript[n, p][z_], Subscript[n, m][z_]} := {{p1[z], p2[z], p3[z]}, {m1[z], m2[z], m3[z]}} {Null, Null} (* testing *) {Subscript[n, p][z], Subscript[n, m][z]} {{p1[z], p2[z], p3[z]}, {m1[z], m2[z], m3[z]}} {Subscript[nn, p][z_], Subscript[nn, m][z_]} := {Outer[Times, Subscript[n, p][z], Subscript[n, p][z]], Outer[Times, Subscript[n, m][z], Subscript[n, m][z]]} {Null, Null} (* testing *) {Subscript[nn, p][z], Subscript[nn, m][z]} {{{p1[z]^2, p1[z] p2[z], p1[z] p3[z]}, {p1[z] p2[z], p2[z]^2, p2[z] p3[z]}, {p1[z] p3[z], p2[z] p3[z], p3[z]^2}}, {{m1[z]^2, m1[z] m2[z], m1[z] m3[z]}, {m1[z] m2[z], m2[z]^2, m2[z] m3[z]}, {m1[z] m3[z], m2[z] m3[z], m3[z]^2}}} Bobby On Wed, 04 Nov 2009 00:41:31 -0600, dushan <dushanm at spinn.net> wrote: > I defined two 3-D vector functions, > {Subscript[n,p][z_], Subscript[n,m][z_]} := {{p1[z],p2[z],p3[z]}, > {m1[z],m2[z],m3 > [z]}} > where p? and m? are simple functions of z. When displayed they appear > as expected. But when I tried to define the dyadics > {Subscript[nn,p][z_], Subscript[nn,m][z_]} := > {Outer[Times, Subscript[n,p][z], Subscript[n,p] > [z]], > Outer[Times, Subscript[n,m][z], Subscript[n,m] > [z]]} > I got the error message that the expression 'is incomplete, more input > is needed'. > > When I separate this into two independent commands, as > Subscript[nn,p][z_] := Outer[Times, Subscript[n,p][z], > Subscript[n,p][z]] > Subscript[nn,m][z_] := Outer[Times, Subscript[n,m][z], > Subscript[n,m][z]] > no error is generated. Probably irrelevant, but I noticed that in > both cases the outer brackets of the 'm' definition were slightly > smaller than those of the 'p' definition. > > To check the result I asked to display the inner product > Subscript[nn,p][z].Subscript[n,p][z] > and got the error message 'Recursion depth 256 exceeded'. > > In fact, when, to reassure myself, I tried again to display Subscript > [n,p][z], I got the same error message. So I went back over the > definitions, and this time > Subscript[nn,p][z].Subscript[n,p][z] > produced the expected answer. > > What could possibly be changing that sometimes, but not always, > produces the error messages in these two cases? I'm at a loss to know > what to watch out for. > > - Dushan > -- DrMajorBob at yahoo.com

**References**:**what's wrong with these expressions?***From:*dushan <dushanm@spinn.net>