Solving a system of equations programmably?
algorithm, c, c++, equation
Solution
You can map it to a matrix system, `A x = b`, where `A` is the coefficient matrix, `b` is the solution vector, and `x` are the unknowns. You can either implement Gaussian elimination, or use a well known library. If you use LAPACK, the routine you want it `dgesv`.
Problem
Possible Duplicate: System of linear equations in C++? I have the following 2 systems of equations: For a,b,c,d: ``` 0 = a * r1_x + b * r1_x * r1_y + c * r1_y + d 1 = a * r2_x + b * r2_x * r2_y + c * r2_y + d 0 = a * r3_x + b * r3_x * r3_y + c * r3_y + d 1 = a * r4_x + b * r4_x * r4_y + c * r4_y + d ``` For e,f,g,h: ``` 0 = e * r1_x + f * r1_x * r1_y + g * r1_y + h 0 = e * r2_x + f * r2_x * r2_y + g * r2_y + h 1 = e * r3_x + f * r3_x * r3_y + g * r3_y + h 1 = e * r4_x + f * r4_x * r4_y + g * r4_y + h ``` I know the values of r1_x, r1_y, r2_x, r2_y, r3_x, r3_y, r4_x, r4_y, and need to solve for a,b,c,d in the first one, and ,e,f,g, h in the second. I know how I would solve these with pencil and paper, but I'm really unsure how to program it. How could I solve the above equations in C or C++ (or psuedocode). Thanks