This program is to find the solution of Ax=b using conjugate gradients algorithm.

  io.c is to deal with data input and output from standin and standout for matrix A and vector b.
  cg.c is the conjugate gradient algorithm function
  
  the test file is test.txt, includes matrix.txt(the matrix A) and vector.txt(the vector b).


Usage is in the form of "./Meifang_HW_12 <test.txt >out"