Optimized seam carving for Julia

seam_carving.jl

function find_min_energy_map2(energy)
    energy  = transpose(energy)
    row,col = size(energy)
    dir_arr = [-1,0,1]

    energy_map         = zeros(row,col)
    energy_map[:, end] = energy[:, end]
    dirs= zeros(Int, row,col)

    @inbounds for c = col-1:-1:1
       local_energy, next_element = min2(energy_map[1,c+1], energy_map[2,c+1])
       energy_map[1,c] = local_energy + energy[1,c]
       dirs[1,c]       =  dir_arr[next_element + 1]
          @inbounds for r=2:row-1
             top    = max(1, r-1)
             bottom = min(row,r+1)

             local_energy, next_element = min3(energy_map[r-1, c+1], energy_map[r, c+1], energy_map[r+1, c+1])
             energy_map[r,c] += local_energy + energy[r,c]
             dirs[r,c]       =  dir_arr[next_element]
          end
       local_energy, next_element = min2(energy_map[row-1,c+1], energy_map[row,c+1])
       energy_map[row,c] = local_energy + energy[row,c]
       dirs[row,c]       =  dir_arr[next_element]
     end

    return transpose(energy_map), transpose(dirs)
end

function min2(a,b)
   return (a<b) ? (a,1) : (b,2)
end

function min3(a,b,c)
   if (a<b)
      if (a<c)
         return a,1
      else
         return c,3
      end
   else
      if (b<c)
         return b,2
      else
         return c,3
      end
   end
end