Update documentation

include/matrix.hpp

@@ -13,6 +13,11 @@
 #include <armadillo>
 
 /** @brief Create a tridiagonal matrix.
+ *  
+ *  create_tridiagonal creates a tridiagonal matrix by first creating a matrix,
+ *  filled with zeros, of size NxN where N is the size of the main diagonal 
+ *  matrix. Then it will fill all the values from the vector parameters into
+ *  the matrix and return it.
  *
  *  @param a Vector for the lower diagonal of size N-1
  *  @param d Vector for the main diagonal of size N
@@ -26,6 +31,11 @@ arma::mat create_tridiagonal(
     const arma::vec& e);
 
 /** @brief Create a tridiagonal matrix.
+ *
+ *  This is an overload that takes doubles for the diagonals instead of 
+ *  vectors. It will create 3 vectors that are filled with the signature
+ *  provided in the arguments, and then call create_tridiagonal with the 
+ *  vectors as the arguments.
  *
  *  @param n The dimensions of the tridiagonal matrix
  *  @param a The signature for the lower diagonal
@@ -37,6 +47,9 @@ arma::mat create_tridiagonal(
 arma::mat create_tridiagonal(int n, double a, double d, double e);
 
 /** @brief Create a symmetric tridiagonal matrix.
+ *
+ *  create_symmetric_tridiagonal creates a symmetric tridiagonal matrix by 
+ *  calling create_tridiagonal with the same signature for the off-diagonals.
  *
  *  @param n The dimensions of the tridiagonal matrix
  *  @param a The signature for the off diagonals
@@ -47,6 +60,11 @@ arma::mat create_tridiagonal(int n, double a, double d, double e);
 arma::mat create_symmetric_tridiagonal(int n, double a, double d);
 
 /** @brief Find the off-diagonal element with the largest absolute value.
+ *
+ *  max_offdiag_symmetric find the element with the largest absolute value
+ *  that isn't in the diagonal. Since this function assumes that the matrix
+ *  that is given is symmetrical, we only need to loop through the upper 
+ *  diagonals of the matrix.
  *
  *  @param A Symmetric matrix
  *  @param k Variable to store the row of the return value