Fortran Programs
(These are Free but no support is provided)
Here are a few FORTRAN programs that can be used for various numerical calculations such as root finding, "curve" fitting, solving systems of linear equations by matrix reduction, and solving differential equations. The quadratic formula, Newton-Raphson method, Least Squares linear fit, Gauss-Jordon Elimination, and fourth order Runge Kutta method are coded in these programs. Feel free to download, use, and/or reference.

Uses the Quadratic Formula to solve for the roots of an equation fitting the form Ax^2+Bx+C=0.
Solves for the root(s) of an equation, using the Newton-Raphson method. Asks for an initial "guess" of the root. 
Uses the Least Squares method to find the best fit straight line for a set of data points. (REQUIRES AN INPUT FILE NAMED LSMIN.DAT TO READ IN NUMBER OF POINTS AND THEN THE DATA POINTS THEMSELVES).
Solves a system of linear equations using the Gaussian Elimination (matricies) method with complete pivoting. Can solve different matrix sizes, determined by the user. (REQUIRES A INPUT DATA FILE NAMED "DATAIN.DAT" TO INPUT THE NUMBER OF ROWS, THE NUMBER OF CONSTANTS, AND THEN THE DATA IN MATRIX FORM).

Uses the RUNGE KUTTA method to solve 4 differential equations simultaneously. The DE's used in the program as an example (which can be changed by you, the user), describe two masses on springs.
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