warikan.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3グループをx[0],x[1],x[2]と定義"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "x = [9376,3600,11442]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "x[0]がx[1]にa[0]貰う、x[0]がx[2]にa[1]貰う、x[1]がx[2]にa[2]貰うと定義"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "a = [0,0,0]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "関数をf(a)と定義"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def f(a):\n",
    "    x_a = [0,0,0]\n",
    "    x_a[0] = x[0] - a[0] - a[1]\n",
    "    x_a[1] = x[1] + a[0] - a[2]\n",
    "    x_a[2] = x[2] + a[1] + a[2]\n",
    "    return abs(x_a[0] - x_a[1]) + abs(x_a[1] - x_a[2]) + abs(x_a[0] - x_a[2])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "学習係数を eta"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "eta = [-0.01, -0.01, -0.01]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "勾配法による勾配計算"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def numerical_gradient(f, x):\n",
    "    h = 1e-4 # 0.0001\n",
    "    grad = [0,0,0]\n",
    "\n",
    "    for idx in range(len(x)):\n",
    "        tmp_val = x[idx]\n",
    "        x[idx] = tmp_val + h\n",
    "        fxh1 = f(x)\n",
    "\n",
    "        x[idx] = tmp_val - h \n",
    "        fxh2 = f(x)\n",
    "\n",
    "        grad[idx] = (fxh1 - fxh2) / (2*h)\n",
    "        x[idx] = tmp_val\n",
    "\n",
    "    return [x * y for (x, y) in zip(eta, grad)]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "勾配法による学習"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1923.7000044771776, -688.6599949750234, -2612.359998543616]\n"
     ]
    }
   ],
   "source": [
    "while f(a) > 10:\n",
    "    tmp = numerical_gradient(f, a)\n",
    "    a = [x + y for (x, y) in zip(tmp, a)]\n",
    "print(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "8140.959990497846\n",
      "8136.060003020793\n",
      "8140.980006481361\n"
     ]
    }
   ],
   "source": [
    "print(x[0] - a[0] - a[1])\n",
    "print(x[1] + a[0] - a[2])\n",
    "print(x[2] + a[1] + a[2])"
   ]
  }
 ],
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