-- abc_la.ads  User problem definitions for a specific PDE to be solved
--          this includes the user choice of degree and discretization
--
--          The problem must be well posed and the solution must be
--          continuous and continuously differentiable
--
-- The general PDE to be solved is:
--  a1(x,y)*uxx(x,y) + b1(x,y)*uxy(x,y) + c1(x,y)*uyy(x,y) +
--  d1(x,y)*ux(x,y) + e1(x,y)*uy(x,y) + f1(x,y)*u(x,y) = c(x,y)
--
with Real_Arrays; -- type Real comes from here
use Real_Arrays;

package abc_la is

-- Define the region for the solution:
-- xmin <= x <= xmax, ymin <= y <= ymax  using  nx by ny points

  xmin:constant :=  -1.0;
  xmax:constant :=   1.0;
  ymin:constant :=  -1.0;
  ymax:constant :=   1.0;
  nx:constant   :=     6;
  ny:constant   :=     5;
  ifcheck:constant :=  1;  -- set  ifcheck = 1 or more, else ifcheck = 0

-- the user must provide all functions, even if only  return 0.0;
-- the functions are implemented in the file  abc.abd
-- A specific set of test functions is covered in abc.txt

function a1(x:Real; y:Real) return Real;
function b1(x:Real; y:Real) return Real;
function c1(x:Real; y:Real) return Real;
function d1(x:Real; y:Real) return Real;
function e1(x:Real; y:Real) return Real;
function f1(x:Real; y:Real) return Real;
function u (x:Real; y:Real) return Real;
           -- must compute boundary, if solution, thenset ifcheck>0
function c (x:Real; y:Real) return Real;
           -- this becomes defined by u and a1 ... f1

end abc_la;