USES SPLIN;
{ Porovnava 2. derivaci funkce cos x s hodnotou ziskanou pomoci splinu
  zadavaji se derivace na okraji jako okraj. podm.
  vysledek se pise do souboru SPL2.DAT}
const
  pi = 3.141592;
{  nbod = 51;
  ndel = 501;}
var
   X,Y, Y2, Y2kon : RealArrayNP;
   xmax,xmin,yp1,ypn,dx,y21,xh,ygs,yfs,dx1: Real;
   i,nbod : integer;
   f1 : text;
BEGIN
   ASSIGN(f1,'spl2.dat');
   REWRITE(f1);
   Writeln('ZADEJ xmin,xmax,nbod');
   Readln(xmin,xmax,nbod);
   dx := (xmax - xmin)/(nbod - 1);
   FOR i := 1 to nbod DO BEGIN
      x[i] := xmin + (i-1)*dx;
      y[i] := cos(x[i]);
      y2kon[i] := -cos(x[i])
   END;
   Writeln (' Zadej derivaci y pro xmin, xmax');
   Readln(yp1,ypn);
   Spline(X,Y,nbod,yp1,ypn,Y2);
   WRITELN('   x             y              d2teor              d2spl');
   FOR i := 1 TO nbod DO BEGIN
       writeln(x[i],y[i],y2kon[i],y2[i]);
       writeln(f1,x[i],y[i],y2kon[i],y2[i])
       END;
   CLOSE(f1)
END.