{
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  "nbformat_minor": 0,
  "metadata": {
    "kernelspec": {
      "display_name": "TensorFlow 2.3 on Python 3.6 (CUDA 10.1)",
      "language": "python",
      "name": "python3"
    },
    "language_info": {
      "codemirror_mode": {
        "name": "ipython",
        "version": 3
      },
      "file_extension": ".py",
      "mimetype": "text/x-python",
      "name": "python",
      "nbconvert_exporter": "python",
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      "version": "3.6.9"
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    "colab": {
      "name": "6-1.sigmoid_function.ipynb",
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  },
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "oXsz2JFUw_Nq"
      },
      "source": [
        "# 시그모이드 활성화 함수"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "wiP3O4uuw_Nr"
      },
      "source": [
        "[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/rickiepark/dl-illustrated/blob/master/notebooks/6-1.sigmoid_function.ipynb)"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "Mw4kUI2Ow_Ns"
      },
      "source": [
        "from math import e"
      ],
      "execution_count": 1,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "2u7mQgEHw_Ns"
      },
      "source": [
        "def sigmoid(z):\n",
        "    return 1/(1+e**-z)"
      ],
      "execution_count": 2,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "pBoFXStpw_Ns",
        "outputId": "385ae9cc-5559-421f-9b33-a889d9fd4100",
        "colab": {
          "base_uri": "https://localhost:8080/"
        }
      },
      "source": [
        "sigmoid(.00001)"
      ],
      "execution_count": 3,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "0.5000024999999999"
            ]
          },
          "metadata": {},
          "execution_count": 3
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "RsGW7IXqw_Nt",
        "outputId": "03912a03-8f7e-443f-e829-b3946668c588",
        "colab": {
          "base_uri": "https://localhost:8080/"
        }
      },
      "source": [
        "sigmoid(10000)"
      ],
      "execution_count": 4,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "1.0"
            ]
          },
          "metadata": {},
          "execution_count": 4
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "J7qiDVKjw_Nt",
        "outputId": "1752c51a-69bb-4c41-820a-967b69700bb5",
        "colab": {
          "base_uri": "https://localhost:8080/"
        }
      },
      "source": [
        "sigmoid(-1)"
      ],
      "execution_count": 5,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "0.2689414213699951"
            ]
          },
          "metadata": {},
          "execution_count": 5
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "G9CubnUzw_Nu",
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        "colab": {
          "base_uri": "https://localhost:8080/"
        }
      },
      "source": [
        "sigmoid(-10)"
      ],
      "execution_count": 6,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "4.539786870243442e-05"
            ]
          },
          "metadata": {},
          "execution_count": 6
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "lR2AsZFsw_Nu",
        "outputId": "730b83ba-9c3a-4e00-e19d-d9f316952805",
        "colab": {
          "base_uri": "https://localhost:8080/"
        }
      },
      "source": [
        "sigmoid(-2.0)"
      ],
      "execution_count": 7,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "0.11920292202211757"
            ]
          },
          "metadata": {},
          "execution_count": 7
        }
      ]
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  ]
}