WinSolver - Linear System of Equations Solver written in C and C++ native Windows API.
WinSolver is a simple but fast and capable linear system solver that is simply a minimal interface and muliline text control wrapped around a command-line solver to allow simple copy/paste of a coefficient matrix (including the constant vector as the last column) into the editor for solving. It is an editor with a [Solve...] button. A convenience that saves creating an input file containing the coefficient matrix and constant vector before calling the solver from the command line with the file containing the coefficient matrix as the argument. Instead, just paste the coefficient matrix in the solver and click [Solve...]. The underlying parser and solver is written entirely in C. (the mtrx_t.[ch] source files contain code for handling direct file input as well)
The linear system solver uses Gauss-Jordan Elimination with full pivoting to solve a system of equations containing any number of unknowns up to the physical memory limits of your computer. See Gaussian Elimination Though the buffer for each line of the coefficient matrix parsed from the edit-control is limited to 8192 characters by default. If your needs are greater, just change the MAXC define at the top of mtrx_t.h (note windows default stack size is generally limited to 512K, so if your lines exceed ~500K, you will need to rewrite and allocate rather than simply changing the constant).
This project is a rewrite of GtkSolver to use a native Windows API interface for those running windows to eliminate the need to install Gtk+2.0 libraries and allow the program to run on any recent version of windows as a standalone program. The base functionality between GtkSolver and this program is identical. The former uses Gtk+2 as the interface, while this code uses the native Win32 API.
The interface is straight forward. The program lauches with a short help message and example of the input format expected in the textview itself. Simply [Clear] (or replace) the help message with your coefficient matrix including the constant vector as the final column and click [Solve...]. The coefficient matrix is read from the window and passed to the solver. The solution vector is written back to the window below the coefficient matrix.
Use Details
The contents of the edit control is converted from wchar_t to char* (multi-byte string) and the initial characters up to the first .+-[0-9] are ignored. The first character containing .+-[0-9] is taken as the start of the coefficient matrix for the system of equations and is passed to the solver. The input format is flexible, but must be an [N x N+1] matrix (representing N equations and N unknowns including the constant vector as the last column). Delimiters between the coefficient values can be anything other than .+-[0-9], and are simply ignored. All values are processed as type double. (if desired, you can change the define for 'T' in mtrx_t.h define a different type)
The format for the coefficient matrix within the edit-control is flexible and could equally be:
3.0 2.0 -4.0 3.0
2.0 3.0 3.0 15.0
5.0 -3.0 1.0 14.0
or
linear system of equations:
3 2 -4 | 3
2 3 3 | 15
5 -3 1 | 14
or
3,2,-4,3
2,3,3,15
5,-3,1,14
or
3x +2y -4z = 3
2x +3y +3z = 15
5x -3y +1z = 14
(note: the only limitation is the '+' or '-' must be the character immediately before the number (e.g. attached to the number). For example if you entered 3x + 2y - 4z = 3, the coefficient for 'z' would be taken as '4' instead of '-4')
Clicking [Help] clears the buffer and redisplays the initial help message.
Taking the contents of the second example above as the contents of the edit window and clicking [Solve...] results in:
linear system of equations:
3 2 -4 | 3
2 3 3 | 15
5 -3 1 | 14
Solution Vector:
x[ 0] : 3.0000000
x[ 1] : 1.0000000
x[ 2] : 2.0000000
(where the formatted solution vector is simply concatenated with the existing text written back to the edit control for display in the window)
Compiling this solver on windows is a simple matter of compiling the windows resource file and then compiling the application. The application can be built with VS10 or later (probably earlier versions as well) You have several options. If space isn't a concern and you want to install the full VS2017 compiler, you can install the VS2017 Community Edition. If you don't want a full VS install or don't have 8G of space to devote to the full install, then all you really need is the Windows v7.1 SDK. While it may be antiquated by some standards, for simple windows applications, it provides the VS10 compiler and all needed libraries.
With either the full VS2017 install or the Windows v7.1 SDK, open Developers Command Prompt (or Windows SDK 7.1 Command Prompt) and simply build the application for the command line. (takes about 15 seconds -- including typing)
To build the resouce file using the windows resource compiler, just change to the directory containing the sources and issue:
rc /Fowinsolver.res winsolver.rc
To buld the application issue:
cl /nologo /W3 /wd4996 /Ox /Fewinsolver /Tp winsolver.cpp /Tc memrealloc.c
/Tc mtrx_t.c user32.lib comctl32.lib gdi32.lib winsolver.res
(the above is all one line - see top of winsolver.cpp for additional details)
That's it. You will now find winsolver.exe in the present directory which can be run by simply typing winsolver. You can also create a shortcut and add it to your start menu as you see fit.
You can also use MinGW or TDM-MinGW to compile the solver. However, to compile on Win32,
**note:** you must first edit MinGW/Include/commctrl.h to change the default
target version, otherwise a number of constants needed by the
controls will not be defined, e.g. make the following changes:
locate (near the top):
/* define _WIN32_IE if you really want it */
#if 0
#define _WIN32_IE 0x0300
#endif
change to:
#if 1
#define _WIN32_IE 0x0500
#endif
Now proceed normally compiling the resource file to object:
windres -o acceltstmg.o acceltst.rc
Then linking the resource as a normal object file when building the solver:
g++ -Wall -Ofast -o acceltstmg acceltst.cpp -lcomctl32 -luser32 -lgdi32 \
acceltstmg.o -Wl,-subsystem,windows
(note: the only drawback to using MinGW to build the solver is that the CLEARTYPE_QUALITY flag is not available to fonts within the edit-control, otherwise there is no difference)
For a bit of background on this problem and solution, see: MinGW 32-bit Error Buttons Not Declared. The change to commctrl.h simply changes a define to enable the required constants, e.g.
Further development will incude saving the current contents of the buffer and setting the output format for the solution vector. Perhaps also allowing the coefficient matrix to be passed via the copy-buffer. If you have additional ideas, open a feature request, or better yet, create a branch, implement the changes and the fill-out a pull request.
This code is licensed under the GPLv2 open-source license contained in LICENSE.txt and copyright David C. Rankin, 2019.