Re: Plot[] problem (plnr) - help !!!

*To*: mathgroup at smc.vnet.net*Subject*: [mg15992] Re: [mg15935] Plot[] problem (plnr) - help !!!*From*: "Richard Finley" <rfinley at medicine.umsmed.edu>*Date*: Fri, 19 Feb 1999 03:27:08 -0500*Sender*: owner-wri-mathgroup at wolfram.com

Alexander, It is not clear to me what you are trying to do?? I presume you mean to use the assignment operator = instead of the comparator ==?? If that is true, and I presume you meant to put the Clear[H] before you define H rather than after?? Even so, you will not be able to plot the function as is since it has real and imaginary parts. Instead try this: a[0]=1 a[1]=.99/50000 H[w_]:= Log[10,Sum[a[k] Exp[I 2 Pi w(-k)], {k,0,1}]] Plot[Abs[H[w],{w,1,100}] or you could plot the Real and Imaginary parts separately. Regards, RF >>> Alexander Sirotkin <root at borjch.math.tau.ac.il> 02/17/99 10:34PM >>> Hi. I'm trying to do most trivial and simple thing - define some function and then Plot[] it. However, I get some very weird error - " ...is not a machine-size real number at ..." Here is the code : a[0]==1 a[1]==0.99/50000 H[w] == Log[10,Sum[a[k] Exp[I 2Pi w(-k)], {k,0,1}]] Clear[H] Plot[H[w], {w, 1, 100}] I've seen some articles (even at www.wolfram.com) about that problem, but NONE of them proposed a working solution !!! Just putting Evaluate[] inside the Plot[] does nothing...