Sigmoid Function

sigmoid.cpp

/**
 * Copyright 2017 ghabxph(c)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is furnished
 * to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#define _WIN32_WINNT 0x0500
#include <windows.h>
#include <iostream>
#include <cmath>
#include <string>

using namespace std;

/**
 *  Calculates the sigmoid of min to max, with a given number of iterations.
 *  @author  ghabxph
 *  @since   2018.1.5
 */

/// ------------------------
/// Prototypes
/// ````````````````````````

/// Sigmoid function
double sigmoid(double value);

/// Retrieves valid integer input from input stream
double getDoubleInput (const char *sMessage);

/// Retrieves valid integer input from input stream
int getIntInput (const char *sMessage);

/// Plots something in the cartesian plane
void plot (HDC hDeviceContext, double x, double y, COLORREF color, double xUnitPerDot, double yUnitPerDot);
/// ------------------------

/// Definitions / Macros
#define CONSOLE_WIDTH  959
#define CONSOLE_HEIGHT 418

/// ------------------------
/// Main Application
/// ````````````````````````
int main()
{
    double minValue = getDoubleInput("Enter min value: ");
    double maxValue = getDoubleInput("Enter max value: ");
    int iterations = getIntInput("Enter number of iterations: ");
    double zoomX = getDoubleInput("Enter ZoomX: ");
    double zoomY = getDoubleInput("Enter ZoomY: ");
    int actualIterations = 0;
    double step = abs(maxValue - minValue) / iterations;
    double result = minValue;
//    cout << "sigmoid(" << minValue << ")\t: " << sigmoid(result) << endl;
//    for (int i = 0; i < iterations; i++) {
//        result += step;
//        actualIterations++;
//        cout << "sigmoid(" << result << ")\t: " << sigmoid(result) << endl;
//    }
//    return 0;

    /// Get console handle
    HWND hConsole = GetConsoleWindow();
    /// Get a handle to device context
    HDC hDeviceContext = GetDC(hConsole);

    COLORREF XEE     = RGB(0xEE, 0xEE, 0xEE);
    COLORREF X66     = RGB(0x66, 0x66, 0x66);
    COLORREF X33     = RGB(0x33, 0x33, 0x33);
    COLORREF X00FF00 = RGB(0x00, 0xFF, 0x00);

    while (true) {
        for (int i = 0; i < CONSOLE_WIDTH; i++) {
            SetPixel(hDeviceContext, i, CONSOLE_HEIGHT / 2, X33);
        }
        for (int i = 0; i < CONSOLE_HEIGHT; i++) {
            SetPixel(hDeviceContext, CONSOLE_WIDTH / 2, i, X33);
        }
        result = minValue;
        for (int i = 0; i < iterations; i++) {
            result += step;
            actualIterations++;
            plot(hDeviceContext, result, sigmoid(result), XEE, CONSOLE_WIDTH / zoomX, CONSOLE_HEIGHT / zoomY);
        }
    }

    ReleaseDC(hConsole, hDeviceContext);
    cin.ignore();

    return 0;
}
/// ------------------------


/// ------------------------
/// Implementations
/// ````````````````````````

/// Sigmoid function
double sigmoid(double value) {
    return 1 / (1 + exp(-value));
}

/// Retrieves valid double input from input stream
double getDoubleInput (const char *sMessage)
{
    bool bInputGood = false;
    double inputVar;
    do {
        cout << sMessage;
        cin >> inputVar;
        bInputGood = cin.good();
        if (bInputGood == false) {
            cout << "Bad input. Please try again." << endl;
        }
        cin.clear();
        cin.ignore(INT_MAX, '\n');
    } while (bInputGood == false);
    return inputVar;
}

/// Retrieves valid double input from input stream
int getIntInput (const char *sMessage)
{
    bool bInputGood = false;
    int inputVar;
    do {
        cout << sMessage;
        cin >> inputVar;
        bInputGood = cin.good();
        if (bInputGood == false) {
            cout << "Bad input. Please try again." << endl;
        }
        cin.clear();
        cin.ignore(INT_MAX, '\n');
    } while (bInputGood == false);
    return inputVar;
}

/// Plots something in the cartesian plane
void plot (HDC hDeviceContext, double x, double y, COLORREF color, double xUnitPerDot, double yUnitPerDot)
{
    int xUnit = (int)(x * 4 * xUnitPerDot);
    int yUnit = (int)(y * 4 * yUnitPerDot);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit - 1, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 0, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 1, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);

    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit - 1, (CONSOLE_HEIGHT / 2) - yUnit + 0, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 0, (CONSOLE_HEIGHT / 2) - yUnit + 0, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 1, (CONSOLE_HEIGHT / 2) - yUnit + 0, color);

    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit - 1, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 0, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);
    SetPixel(hDeviceContext, (CONSOLE_WIDTH / 2) + xUnit + 1, (CONSOLE_HEIGHT / 2) - yUnit + 1, color);
}
/// ------------------------