I am trying to use R's solve() function to find the solution to a system of linear equations. The coefficients matrix is 2X2. My code below is written into an R file that I execute after it finished being written.
Before calling solve, I check to see if the determinant is not 0:
int prod1 = x * y_2;
int prod2 = x_2 * y;
int determinant = prod1 - prod2;
if (determinant != 0) {
strcat(Q, "A = array(c(");
strcat(Q, numx);
strcat(Q, ", ");
strcat(Q, numx_2);
strcat(Q, ", ");
strcat(Q, numy);
strcat(Q, ", ");
strcat(Q, numy_2);
strcat(Q, "), dim = c(2,2,1))\n");
strcat(Q, "b = c(");
strcat(Q, numz);
strcat(Q, ", ");
strcat(Q, numz_2);
strcat(Q, ")\n");
strcat(Q, "solve(A[,,1],b)\n");
}
I then fputs Q into a R file that my program then opens and compute the commands. However, my if statement doesn't seem to be correctly catching the singular matrices.
I get an output like this
Execution halted
Error in solve.default(A[, , 1], b) :
Lapack routine dgesv: system is exactly singular: U[2,2] = 0
Calls: solve -> solve.default
//repeat above line for another 60 lines//
the value of determinant: 1
the value of determinant: 1
the value of determinant: 1the value of determinant: 1
the value of determinant: 1the value of determinant: 1
the value of determinant: 1the value of determinant: 1
the value of determinant: 1the value of determinant: 1
the value of determinant: 2the value of determinant: 2
the value of determinant: 2the value of determinant: 2
//this continues for another 20 lines
Error in solve.default(A[, , 1], b) :
Lapack routine dgesv: system is exactly singular: U[2,2] = 0
Calls: solve -> solve.default
Execution halted
//this continue again till I CTRL + C
How am I not catching the singular matrices?
