Update read me

SPEX/SPEX_Cholesky/README.txt

@@ -1,16 +1,21 @@
 
-SPEX_Cholesky is software package used to solve a sparse SPD linear systems exactly using the Sparse Cholesky factorization. It comprises both an integer-preserving up-looking and integer-preserving left-looking Cholesky factorization.
+SPEX_Cholesky is software package used to solve a sparse SPD or symmetric negative definite
+and symmetric indefinite with nonzero leading principle minors linear systems exactly using
+the Sparse Cholesky factorization. It comprises both an integer-preserving up-looking and 
+integer-preserving left-looking Cholesky and LDL factorization
 
-*********SPEX_Cholesky*********
+*********SPEX_cholesky*********
 Purpose: Exactly solve an SPD sparse system of linear equations using a given
          input matrix and right hand side vector file. This code can output the
          final solution to a user specified output file in either double
          precision or full precision rational numbers. If you intend to use
-         SPEX_Cholesky within another program, refer to examples for help with
+         SPEX_cholesky within another program, refer to examples for help with
+         this.
+
+*********SPEX_ldl*********
+Purpose: Exactly solve a symmetric system of equations with nonzero leading
+         principle minors. This code can output the
+         final solution to a user specified output file in either double
+         precision or full precision rational numbers. If you intend to use
+         SPEX_ldl within another program, refer to examples for help with
          this.
-
-*********example_simple*********
- Purpose: Demonstrate the simple interface of SPEX_Cholesky for a matrix to be read in
-
-*********example_extended*********
-Purpose: Demonstrate the extended interface of SPEX_Cholesky for a matrix to be read in