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  question about rank error in function

  Posted by fav_pa on May 9, 2024 at 12:22 am

  I tried to abstract the Newton-Raphson method in this function, where the user can input a value of c, a first guess x0, and p, the value at which x is raised. However i get a rank error when applying it to for example:
  fbis [2; 1; 3].

  Can someone explain why?

  fbis : {[c_, x0, p_] {[xn ; c; p] xn – ((xn xexp p)-c)%(p * xn xexp p-1)}[; c_; p_]\[x0]}

  Thank you!

  fav_pa replied 6 months, 2 weeks ago 2 Members · 2 Replies
• 2 Replies

• 

  rocuinneagain

  Member

  May 9, 2024 at 8:29 am

  , rather than ; separating the arguments of fbis. Otherwise runs fine:

  q)fbis:{[c_;x0;p_]{[xn ;c;p] xn-((xn xexp p)-c)%(p*xn xexp p-1)}[;c_;p_]\[x0]}
  q)fbis[2;1;3]
  1
  1.333333
  1.263889
  1.259933
  1.259921
  1.259921

  • 

    fav_pa

    Member

    May 10, 2024 at 2:36 am

    thank you!
    Silly mistake

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