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R: Local iterator

• To: mathgroup at smc.vnet.net
• Subject: [mg29398] R: Local iterator
• From: "Vincenzo Vasta" <vvasta at btinternet.com>
• Date: Sat, 16 Jun 2001 22:43:48 -0400 (EDT)
• References: <9gevtc$7l0$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Given a function y = f[x] I would like to write a function that returns,
for a given interval and a
given step, the maximum value of y, and the x that generated this value. For
example:

 In[4]  :=  funMax[ Log[x]/x^3 ,x ,1 ,3 ,0.001 ]
 Out[4]=  {0.122626, 1.396}

With my very little knowledge of Mathematica I wrote funMax like this:

  Clear[funMax];
  SetAttributes[funMax, HoldAll];
  funMax[fun_, v_, x1_, x2_, step_] := Block[
    {v, maxVal = {0, 0} , fval},
    For[v = x1, v <= x2, v += step,
      fval = fun;
      If [maxVal[[1]] <  fval,
        maxVal = { fval, v}, 0]
      ];
    maxVal
    ]

This function works and I'm happy with that but I would like to know how can
I write it using an
 iterator. It is just a curiosity about the language.

Thanks for your help
Vincenzo