{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "full (generic function with 1 method)"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# For kernel 0.4.5\n",
    "# This the original file, plus improved getindex() and isassigned()\n",
    "immutable Hankel{T} <: AbstractArray{T, 2}\n",
    "    c :: Vector{T}\n",
    "end\n",
    "\n",
    "Hankel{T}(c::Vector{T}) = length(c) % 2 == 1 ? Hankel{T}(c) : throw(ArgumentError(\"\"))\n",
    "\n",
    "#XXX Inefficient but works\n",
    "# getindex(H::Hankel, i, j) = getindex(full(H), i, j)\n",
    "# isassigned(H::Hankel, i, j) = isassigned(full(H), i, j)\n",
    "import Base.getindex, Base.isassigned, Base.size\n",
    "getindex(H::Hankel, i, j) = H.c[i+j-1]\n",
    "isassigned(H::Hankel,i,j) = isassigned(H.c,i+j-1)\n",
    "size(H::Hankel, r::Int) = (r==1 || r==2) ? 1 + div(length(H.c),2) :\n",
    "    throw(ArgumentError(\"Invalid dimension $r\"))\n",
    "size(H::Hankel) = size(H,1), size(H,2)\n",
    "\n",
    "function full{T}(H::Hankel{T})\n",
    "    n=size(H, 1)\n",
    "    M=Array(T, n, n)\n",
    "    for i=1:n\n",
    "        M[:,i] = H.c[i:i+n-1]\n",
    "    end\n",
    "    M\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6x6 Hankel{Int64}:\n",
       " 1  2  3  4   5   6\n",
       " 2  3  4  5   6   7\n",
       " 3  4  5  6   7   8\n",
       " 4  5  6  7   8   9\n",
       " 5  6  7  8   9  10\n",
       " 6  7  8  9  10  11"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a=collect(1:11)\n",
    "H=Hankel(a)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now change the kernel to 5.0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "WARNING: Method definition (::Type{Main.Hankel})(Array{#T<:Any, 1}) in module Main at In[1]:3 overwritten at In[1]:6.\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "full (generic function with 1 method)"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# After kernel change to 5.0\n",
    "immutable Hankel{T} <: AbstractArray{T, 2}\n",
    "    c :: Vector{T}\n",
    "end\n",
    "\n",
    "Hankel{T}(c::Vector{T}) = length(c) % 2 == 1 ? Hankel{T}(c) : throw(ArgumentError(\"\"))\n",
    "\n",
    "#XXX Inefficient but works\n",
    "# getindex(H::Hankel, i, j) = getindex(full(H), i, j)\n",
    "# isassigned(H::Hankel, i, j) = isassigned(full(H), i, j)\n",
    "import Base.getindex, Base.isassigned, Base.size\n",
    "getindex(H::Hankel, i, j) = H.c[i+j-1]\n",
    "isassigned(H::Hankel,i,j) = isassigned(H.c,i+j-1)\n",
    "size(H::Hankel, r::Int) = (r==1 || r==2) ? 1 + div(length(H.c),2) :\n",
    "    throw(ArgumentError(\"Invalid dimension $r\"))\n",
    "size(H::Hankel) = size(H,1), size(H,2)\n",
    "\n",
    "function full{T}(H::Hankel{T})\n",
    "    n=size(H, 1)\n",
    "    M=Array(T, n, n)\n",
    "    for i=1:n\n",
    "        M[:,i] = H.c[i:i+n-1]\n",
    "    end\n",
    "    M\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "MethodError",
     "evalue": "MethodError: isassigned(::Hankel{Int64}, ::Int64, ::Int64) is ambiguous. Candidates:\n  isassigned(H::Hankel, i, j) at In[1]:13\n  isassigned(a::AbstractArray, i::Int64...) at abstractarray.jl:185",
     "output_type": "error",
     "traceback": [
      "MethodError: isassigned(::Hankel{Int64}, ::Int64, ::Int64) is ambiguous. Candidates:\n  isassigned(H::Hankel, i, j) at In[1]:13\n  isassigned(a::AbstractArray, i::Int64...) at abstractarray.jl:185",
      "",
      " in alignment(::IOContext{Base.AbstractIOBuffer{Array{UInt8,1}}}, ::Hankel{Int64}, ::Array{Int64,1}, ::Array{Int64,1}, ::Int64, ::Int64, ::Int64) at ./show.jl:1277",
      " in print_matrix(::IOContext{Base.AbstractIOBuffer{Array{UInt8,1}}}, ::Hankel{Int64}, ::String, ::String, ::String, ::String, ::String, ::String, ::Int64, ::Int64) at ./show.jl:1407",
      " in print_matrix(::IOContext{Base.AbstractIOBuffer{Array{UInt8,1}}}, ::Hankel{Int64}, ::String, ::String, ::String) at ./show.jl:1379",
      " in #showarray#330(::Bool, ::Function, ::IOContext{Base.AbstractIOBuffer{Array{UInt8,1}}}, ::Hankel{Int64}, ::Bool) at ./show.jl:1618",
      " in limitstringmime(::MIME{Symbol(\"text/plain\")}, ::Hankel{Int64}) at /home/slap/.julia/v0.5/IJulia/src/execute_request.jl:31",
      " in display_dict(::Hankel{Int64}) at /home/slap/.julia/v0.5/IJulia/src/execute_request.jl:46",
      " in execute_request(::ZMQ.Socket, ::IJulia.Msg) at /home/slap/.julia/v0.5/IJulia/src/execute_request.jl:200",
      " in eventloop(::ZMQ.Socket) at /home/slap/.julia/v0.5/IJulia/src/eventloop.jl:8",
      " in (::IJulia.##9#15)() at ./task.jl:360"
     ]
    }
   ],
   "source": [
    "a=collect(1:11)\n",
    "Hankel(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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