cg, a C code which implements a simple version of the conjugate gradient (CG) method for solving a system of linear equations of the form A*x=b, suitable for situations in which the matrix A is positive definite (only real, positive eigenvalues) and symmetric.
The computer code and data files made available on this web page are distributed under the MIT license
cg is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.
cg_rc, a C code which implements the conjugate gradient method for solving a positive definite sparse linear system A*x=b, using reverse communication.
SPARSE_DISPLAY, a C code which can read information defining a matrix of numbers and display the sparsity pattern or location of the nonzero elements using gnuplot. This operation is already available in the built-in MATLAB "spy" command.
WATHEN, a C code which compares storage schemes (full, banded, sparse triplet) and solution strategies (Linpack full, Linpack banded, conjugate gradient) for linear systems involving the Wathen matrix, which can arise when solving a problem using the finite element method (FEM).