Added simpler example, worked on readme.

README.md

@@ -35,10 +35,60 @@ I've added two things:
 ### Usage
 
 There are two different ways to use this library.  The first is via the
-minre\_ez\_t class which provides a simplified interface to the method and the
+minres\_ez\_t class which provides a simplified interface to the method and the
 second is via the minres_solver function which give you more control, but
 requires a bit more work on the part of the user. 
 
+#### minres_ez_t
+
+To use the `minres_ez_t` class, you have to provide the matrix `A` in sparse
+form, using three arrays: the row indices, column indices, and the nonzero
+elements.  Here is an example:
+
+
+```fortran
+program minres_ez_example_1
+    ! 
+    ! Example program demonstrating the use of minres_ez_t to solve 
+    ! linear systems of the form Ax = b and (A - shift*I)x = b where
+    ! A is symmetric.
+    ! 
+    use, intrinsic :: iso_fortran_env, only : dp=>real64
+    use minres, only : minres_ez_t
+    use minres, only : minres_info_t
+    implicit none
+
+    integer,  parameter :: n         = 3                               ! size of matrix A (symmetric)
+    integer,  parameter :: nnz       = 7                               ! number of nonzero elem. in A 
+    integer,  parameter :: irow(nnz) = [1, 2, 3, 2, 3, 1, 2]           ! row indices nonzero elem. of A
+    integer,  parameter :: icol(nnz) = [1, 2, 3, 1, 2, 2, 3]           ! col indices nonzero elem. of A
+    real(dp), parameter :: a(nnz)    = real([3, 2, 1, 4, 2, 4, 2], dp) ! nonzero elem. of A
+    real(dp), parameter :: b(n)      = real([1, 1, 1], dp)             ! the rhs vector b
+
+    type(minres_ez_t)   :: minres_ez   ! the main ez solver class
+    type(minres_info_t) :: minres_info ! information on solution 
+    real(dp)            :: x(n)        ! the solution vector x
+
+    ! Set some options
+    minres_ez % rtol   = 1.0e-13
+    minres_ez % checka = .true.  
+
+    ! display settings
+    call minres_ez % print()
+
+    ! Solve linear system
+    call minres_ez % solve(irow, icol, a, b, x, minres_info)
+
+    ! Print info on result
+    call minres_info % print()
+
+end program minres_ez_example_1
+
+```
+
+
+
+
 ### Compiling
 
 A [Fortran Package Manager](https://github.com/fortran-lang/fpm) manifest file is included, so that the library and test cases can be compiled with FPM. For example:

example/minres_ez_example_1.f90

@@ -0,0 +1,36 @@
+program minres_ez_example_1
+    ! 
+    ! Example program demonstrating the use of minres_ez_t to solve 
+    ! linear systems of the form Ax = b and (A - shift*I)x = b where
+    ! A is symmetric.
+    ! 
+    use, intrinsic :: iso_fortran_env, only : dp=>real64
+    use minres, only : minres_ez_t
+    use minres, only : minres_info_t
+    implicit none
+
+    integer,  parameter :: n         = 3                               ! size of matrix A (symmetric)
+    integer,  parameter :: nnz       = 7                               ! number of nonzero elem. in A 
+    integer,  parameter :: irow(nnz) = [1, 2, 3, 2, 3, 1, 2]           ! row indices nonzero elem. of A
+    integer,  parameter :: icol(nnz) = [1, 2, 3, 1, 2, 2, 3]           ! col indices nonzero elem. of A
+    real(dp), parameter :: a(nnz)    = real([3, 2, 1, 4, 2, 4, 2], dp) ! nonzero elem. of A
+    real(dp), parameter :: b(n)      = real([1, 1, 1], dp)             ! the rhs vector b
+
+    type(minres_ez_t)   :: minres_ez   ! the main ez solver class
+    type(minres_info_t) :: minres_info ! information on solution 
+    real(dp)            :: x(n)        ! the solution vector x
+
+    ! Set some options
+    minres_ez % rtol   = 1.0e-13
+    minres_ez % checka = .true.  
+
+    ! display settings
+    call minres_ez % print()
+
+    ! Solve linear system
+    call minres_ez % solve(irow, icol, a, b, x, minres_info)
+
+    ! Print info on result
+    call minres_info % print()
+
+end program minres_ez_example_1

example/minres_ez_example.f90 → example/minres_ez_example_2.f90

@@ -1,7 +1,8 @@
-program main
+program minres_ez_example_2 
     ! 
     ! Example program demonstrating the use of minres_ez_t to solve 
-    ! linear systems of the form Ax = b and (A - shift*I)x = b
+    ! linear systems of the form Ax = b and (A - shift*I)x = b where
+    ! A is symmetric.
     ! 
     use, intrinsic :: iso_fortran_env, only : dp=>real64
     use minres, only : minres_ez_t
@@ -126,4 +127,4 @@ subroutine sparse_mul(irow, icol, a, x, y)
     end subroutine sparse_mul
 
 
-end program main
+end program minres_ez_example_2