Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

problem evaluating a function on a list

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69867] problem evaluating a function on a list
  • From: wtplasar at ehu.es
  • Date: Tue, 26 Sep 2006 00:59:27 -0400 (EDT)

Hi everyone,

I have to ask for your advise once again.

I have this function

H[x_, om_, 
    or_, H0_] := If[Im[om - 4*om^(2/3)*or^(1/3) + 2*
          or + 2*Sqrt[or]*Sqrt[om + or]] == 0. && -1 + om - 4*om^(2/3)
*or^(1/
            3) + 2*or + 2*Sqrt[or]*Sqrt[om + or] < 0, H0*((1 - om - 
2*or - 2*
      Sqrt[or]*Sqrt[om + or])*(1 + x)^2 + (Sqrt[or] + Sqrt[or + om*(1 
+ 
          x)^3])^2),  I]

and I want to evaluate it at a list

xlist = {0.09, 0.17, 0.27, 0.4, 0.88, 1.3, 1.43, 1.53, 1.75};

When I choose parameters so that a list of real values should be 
obtained everything seems to be fine as one can see if for instance we 
evaluate

H[xlist, 0.4, 0.1, 70]

(my result is {81.138, 92.4217, 108.473, 132.803, 261.891, 435.859, 
503.238, 559.829, 699.774})

whereas in the cases I would expect the result to be 
{I,I,I,I,I,I,I,I,I}

I get simply one single 

I 

instead, as one can see from evaluation of 

H[xlist, -0.4, 0.1, 70].

Can someone indicate why this happens, and how I can get the
desired list which looks like {I,I,I,I,I,I,I,I,I}?

Thanks in advance for your time,

Ruth



  • Prev by Date: Re: How to deal with this problem!
  • Next by Date: Re: Help: How to deal with this problem!
  • Previous by thread: Re: How to deal with this problem!
  • Next by thread: Re: problem evaluating a function on a list