rev_matr function matr_rev matr matr const var integer t1 t2 real ext

// rev_matr
function matr_rev(a:matr):matr;
const n=3;
var
	i,j,k,l :integer;
        t1, t2      :real;
	ext :array[1..n, 1..n*2] of real;
	a1, a2, a3  :matr;

begin
        for i:=1 to n do begin
            for j:=1 to 2*n do
                if j<= n then
                    ext[i,j]:=a[i,j]
                else
                    ext[i,j]:=0;
            ext[i,n+i]:=1;
        end;


        for i:=1 to n-1 do begin
            for j:=i+1 to n do begin
            t1:=ext[i,i];t2:=ext[j,i];
                for k:=1 to 2*n do begin 
                    ext[j,k]:=ext[j,k]*t1+(-1)*ext[i,k]*t2;
                end;
            end;
        end;


        for i:=0 to n-2 do begin
            for j:=1 to n-1 do begin
            if j<n-i then
            begin
                t1:=ext[j,j+i+1];t2:=ext[j+i+1,j+i+1];
                for k:=1 to 2*n do begin
                    ext[j,k]:=(-1)*ext[j,k]*t2+ext[j+1+i,k]*t1;
                end;
            end;
            end;
        end;


        for i:=1 to n do
            for j:=1 to n do
                matr_rev[i,j]:=ext[i,j+n]/ext[i,i];

end;
// end_ rev_matr