// EigenVV2x2.cpp (c) Wednesday, September 3, 2025
// by James Pate Williams, Jr., BA, BS, MSwE, PhD
// Solution to Exercise 1.11 in "Quantum Chemistry
// an Introduction to Advanced Electronic Structure
// Theory (c) 1996 by Attila Szabo and Neil S. Ostlund
#include "pch.h"
#include "framework.h"
#include "EigenVV2x2.h"
#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst; // current instance
WCHAR szTitle[MAX_LOADSTRING]; // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name
std::wstring text; // output wide string
// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM);
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: Place code here.
// Initialize global strings
LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadStringW(hInstance, IDC_EIGENVV2X2, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_EIGENVV2X2));
MSG msg;
// Main message loop:
while (GetMessage(&msg, nullptr, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
//
// FUNCTION: MyRegisterClass()
//
// PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_EIGENVV2X2));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_EIGENVV2X2);
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
//
// FUNCTION: InitInstance(HINSTANCE, int)
//
// PURPOSE: Saves instance handle and creates main window
//
// COMMENTS:
//
// In this function, we save the instance handle in a global variable and
// create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance; // Store instance handle in our global variable
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
#define IDC_STATIC1 1000
#define IDC_STATIC2 1010
#define IDC_STATIC3 1020
#define IDC_STATIC4 1030
#define IDC_EDIT_A11 2000
#define IDC_EDIT_A12 2010
#define IDC_EDIT_A21 2020
#define IDC_EDIT_A22 2030
#define IDC_EDIT_MULTILINE 3000
#define IDC_BUTTON_COMPUTE 4000
#define IDC_BUTTON_CANCEL 4010
//
// FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
// PURPOSE: Processes messages for the main window.
//
// WM_COMMAND - process the application menu
// WM_PAINT - Paint the main window
// WM_DESTROY - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static HFONT hFont = { };
static HWND hEditMultiline = { };
static HWND hEditA11 = { };
static HWND hEditA12 = { };
static HWND hEditA21 = { };
static HWND hEditA22 = { };
switch (message)
{
case WM_CREATE:
{
hFont = CreateFont(16, 0, 0, 0, FW_NORMAL, FALSE, FALSE, FALSE,
ANSI_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
DEFAULT_QUALITY, DEFAULT_PITCH | FF_SWISS, L"Courier New Bold");
CreateWindowEx(0, L"STATIC", L"A[1][1]:", WS_CHILD | WS_VISIBLE,
10, 10, 80, 20, hWnd, (HMENU)IDC_STATIC1, hInst, NULL);
CreateWindowEx(0, L"STATIC", L"A[1][2]:", WS_CHILD | WS_VISIBLE,
10, 40, 80, 20, hWnd, (HMENU)IDC_STATIC2, hInst, NULL);
CreateWindowEx(0, L"STATIC", L"A[2][1]:", WS_CHILD | WS_VISIBLE,
10, 70, 80, 20, hWnd, (HMENU)IDC_STATIC3, hInst, NULL);
CreateWindowEx(0, L"STATIC", L"A[2][2]:", WS_CHILD | WS_VISIBLE,
10, 100, 80, 20, hWnd, (HMENU)IDC_STATIC4, hInst, NULL);
hEditA11 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
100, 10, 200, 20, hWnd, (HMENU)IDC_EDIT_A11, hInst, NULL);
hEditA12 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
100, 40, 200, 20, hWnd, (HMENU)IDC_EDIT_A12, hInst, NULL);
hEditA21 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
100, 70, 200, 20, hWnd, (HMENU)IDC_EDIT_A21, hInst, NULL);
hEditA22 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
100, 100, 200, 20, hWnd, (HMENU)IDC_EDIT_A22, hInst, NULL);
hEditMultiline = CreateWindowEx(
WS_EX_CLIENTEDGE, // Extended style for sunken border
TEXT("EDIT"), // Class name
TEXT(""), // Initial text (can be blank)
WS_CHILD | WS_VISIBLE | WS_VSCROLL | ES_AUTOHSCROLL |
ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL | WS_HSCROLL | WS_VSCROLL,
310, 10, 300, 300, // Position and size
hWnd, // Parent window handle
(HMENU)IDC_EDIT_MULTILINE, // Unique control ID
hInst, // Application instance
NULL // Extra parameter
);
CreateWindowEx(0, L"BUTTON", L"Compute", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
10, 130, 80, 30, hWnd, (HMENU)IDC_BUTTON_COMPUTE, hInst, NULL);
CreateWindowEx(0, L"BUTTON", L"Cancel", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
220, 130, 80, 30, hWnd, (HMENU)IDC_BUTTON_CANCEL, hInst, NULL);
SendMessage(hEditMultiline, WM_SETFONT, (WPARAM)hFont, TRUE);
SetDlgItemText(hWnd, IDC_EDIT_A11, L"3");
SetDlgItemText(hWnd, IDC_EDIT_A12, L"1");
SetDlgItemText(hWnd, IDC_EDIT_A21, L"1");
SetDlgItemText(hWnd, IDC_EDIT_A22, L"3");
}
break;
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDC_BUTTON_COMPUTE:
{
WCHAR line[128] = L"";
text = L"";
// eigenvalues
std::vector<double> omega(3);
// matrix
std::vector<std::vector<double>> A(3,
std::vector<double>(3));
std::vector<std::vector<double>> B(3,
std::vector<double>(3));
// eigenvectors
std::vector<std::vector<double>> c(3,
std::vector<double>(3));
GetWindowText(hEditA11, line, 128);
std::wstring A11Str(line);
A[1][1] = std::stod(A11Str);
GetWindowText(hEditA12, line, 128);
std::wstring A12Str(line);
A[1][2] = std::stod(A12Str);
GetWindowText(hEditA21, line, 128);
std::wstring A21Str(line);
A[2][1] = std::stod(A21Str);
GetWindowText(hEditA22, line, 128);
std::wstring A22Str(line);
A[2][2] = std::stod(A22Str);
double term1 = A[1][1] + A[2][2];
double term2 = pow(A[2][2] - A[1][1], 2.0);
double term3 = 4.0 * A[1][2] * A[2][1];
// compute eigenvalues
omega[1] = 0.5 * (term1 - sqrt(term2 + term3));
omega[2] = 0.5 * (term1 + sqrt(term2 + term3));
swprintf_s(line, L"Eigenvalues:\r\n\r\n");
text += std::wstring(line);
swprintf_s(line, L"omega 1 = %13.10lf\r\n", omega[1]);
text += std::wstring(line);
swprintf_s(line, L"omega 2 = %13.10lf\r\n\r\n", omega[2]);
text += std::wstring(line);
// compute eigenvalues using a unitary transformation
// matrix A must be symmetric
double theta0 = 0.0;
if (A[1][1] == A[2][2])
{
theta0 = 0.5 * acos(0.0);
}
else
{
theta0 = 0.5 * atan(2.0 * A[1][2] /
(A[1][1] - A[2][2]));
}
// compute the eigenvalues
omega[1] = A[1][1] * pow(cos(theta0), 2.0) +
A[2][2] * pow(sin(theta0), 2.0) +
A[1][2] * sin(2.0 * theta0);
omega[2] = A[1][1] * pow(cos(theta0), 2.0) +
A[2][2] * pow(sin(theta0), 2.0) -
A[1][2] * sin(2.0 * theta0);
swprintf_s(line, L"Eigenvalues:\r\n\r\n");
text += std::wstring(line);
swprintf_s(line, L"omega 1 = %13.10lf\r\n", omega[1]);
text += std::wstring(line);
swprintf_s(line, L"omega 2 = %13.10lf\r\n\r\n", omega[2]);
text += std::wstring(line);
// compute eigenvectors
c[1][1] = cos(theta0);
c[1][2] = sin(theta0);
c[2][1] = sin(theta0);
c[2][2] = -cos(theta0);
swprintf_s(line, L"Eigenvectors:\r\n\r\n");
text += std::wstring(line);
swprintf_s(line, L"c 11 = %13.10lf\r\n", c[1][1]);
text += std::wstring(line);
swprintf_s(line, L"c 12 = %13.10lf\r\n", c[1][2]);
text += std::wstring(line);
swprintf_s(line, L"c 21 = %13.10lf\r\n", c[2][1]);
text += std::wstring(line);
swprintf_s(line, L"c 22 = %13.10lf\r\n", c[2][2]);
text += std::wstring(line);
SetWindowText(hEditMultiline, text.c_str());
break;
}
case IDC_BUTTON_CANCEL:
{
PostQuitMessage(0);
break;
}
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
}
Tag: software
Microsoft Visual Studio 2019 Community Version – Creating and Using a C Based Dynamic Link Library © March 22, 2024, by James Pate Williams, Jr.
Create a solution using the DLL C++ DLL template. Rename pch.cpp to pch.c and dllmain.cpp to dllmain.c. Add a header file for the DLL containing the following macro:
#define DLL_Export __declspec(dllexport)
Mark all the exportable functions in the DLL header file with the DLL_Export macro. Suppose the DLL is named CSortingDLL. Next create a console C++ project in the DLL solution to use the DLL. Open the Properties page of the console app. If you want to use the ASCII character set, select the Advanced Configuration Properties, and set the Character Set to Not Set. Now open the C/C++ General Property and under Additional Include Directories add ..\CSortingDLL\;. Do not include the previous period mark. Next open the Linker General Property page. Set Additional Library Directories to ..\CSortingDLL\$(IntDir);. The penultimate step is to set the Linker Input Additional Dependencies to CSortingDLL.lib;. The final step for the app is to add a reference to CSortingDLL. Now you have a functioning DLL and an app using the DLL. If you have any questions, please contact me via email at jamespate@mac.com. Also, Microsoft has a DLL walkthrough complete with source code. I will add my CSortingDLL header source code as a PDF document.
Numerical Explorations 