{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# repmat"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "An alternative implementation of `repmat` using the new in-place tools."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    ":ext FlexibleContexts\n",
    "\n",
    "import Numeric.LinearAlgebra\n",
    "import Numeric.LinearAlgebra.Devel"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "m = (3><4)[1..] :: Matrix Z"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(3><4)\n",
       " [ 1,  2,  3,  4\n",
       " , 5,  6,  7,  8\n",
       " , 9, 10, 11, 12 ]"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "m"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import Control.Monad.ST"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "rpmt m i j = runST $ do\n",
    "    x <- newUndefinedMatrix RowMajor dr dc\n",
    "    sequence_ [ setMatrix x a b m | a <- [0,r..dr], b <-[0,c..dc] ]\n",
    "    unsafeFreezeMatrix x\n",
    "  where\n",
    "    (r,c) = size m\n",
    "    dr = i*r\n",
    "    dc = j*c"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(6><12)\n",
       " [ 1,  2,  3,  4, 1,  2,  3,  4, 1,  2,  3,  4\n",
       " , 5,  6,  7,  8, 5,  6,  7,  8, 5,  6,  7,  8\n",
       " , 9, 10, 11, 12, 9, 10, 11, 12, 9, 10, 11, 12\n",
       " , 1,  2,  3,  4, 1,  2,  3,  4, 1,  2,  3,  4\n",
       " , 5,  6,  7,  8, 5,  6,  7,  8, 5,  6,  7,  8\n",
       " , 9, 10, 11, 12, 9, 10, 11, 12, 9, 10, 11, 12 ]"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "rpmt m 2 3"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Haskell",
   "language": "haskell",
   "name": "haskell"
  },
  "language_info": {
   "codemirror_mode": "ihaskell",
   "file_extension": ".hs",
   "name": "haskell",
   "version": "7.10.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}