/******************************************************/
/* laplace standart library 21.12.1996 by P!\K / Un0X */
/******************************************************/

/******************************************************/
/* umatrix()                                          */
/*   create square matrix of ones in the main         */
/*   diagonal                                         */
/******************************************************/

procedure umatrix(n)
{
  return( matrix(n,n,a,b,
	    if (a == b)
		1;
	    else
		0;
	  )
	);
}

/******************************************************/
/* angle()                                            */
/*   returns the angle between to vectors             */
/******************************************************/

procedure angle(a,b)
{
  return(
	  acos(
		a * b / (abs(a) * abs(b))
	      )
	);
}