/** This contains functions to find the "argmin" of a function, that is,
    given a single-argument function and a list of input values, returns an
    array of the input value(s) where the function has the minimum value.
*/
argmin[f, data] :=
{
   min = undef
   results = new array

   for arg = data
   {
      val = f[arg]
      if min == undef
      {
         min = val
         results.push[arg]
      } else
      {
         if val < min    // New minimum, replace results list
         {
            results = [arg]
            min = val
         } else
            if val == min  // Identical min, push arg to arg list
               results.push[arg]
      }
   }

   return results
}

/** This contains functions to find the "argmax" of a function, that is,
    given a single-argument function and a list of input values, returns an
    array of the input value(s) where the function has the maxmium value.
*/
argmax[f, data] :=
{
   max = undef
   results = new array

   for arg = data
   {
      val = f[arg]
      if max == undef
      {
         max = val
         results.push[arg]
      } else
      {
         if val > max    // New maximum, replace results list
         {
            results = [arg]
            max = val
         } else
            if val == max  // Identical max, push arg to arg list
               results.push[arg]
      }
   }

   return results
}


/*
// Example usages
squareFunc = {|x| x^2}
data = [-1, 1, -2]
println["argmin: " + argmin[squareFunc, data]]
println["argmax: " + argmax[squareFunc, data]]
println[]

data = [[2,-3],[3,5],[2,5],[-2,3],[-2,-3]]
product = getFunction["product", 1]
println["argmin: " + argmin[product, data]]
println["argmax: " + argmax[product, data]]
*/