def _initial_nodes_a(n, k):
 tauk = _compute_tauk(n, k)
 sigk = (cos((0.5 * tauk)) ** 2)
 a = ((n % 2) - 0.5)
 nu = (((4.0 * floor((n / 2.0))) + (2.0 * a)) + 2.0)
 xksq = ((nu * sigk) - ((1.0 / (3.0 * nu)) * (((5.0 / (4.0 * ((1.0 - sigk) ** 2))) - (1.0 / (1.0 - sigk))) - 0.25)))
 return xksq

def _initial_nodes_a ( n , k ) : tauk = _compute_tauk ( n , k ) sigk = ( cos ( ( 0.5 * tauk ) ) ** 2 ) a = ( ( n % 2 ) - 0.5 ) nu = ( ( ( 4.0 * floor ( ( n / 2.0 ) ) ) + ( 2.0 * a ) ) + 2.0 ) xksq = ( ( nu * sigk ) - ( ( 1.0 / ( 3.0 * nu ) ) * ( ( ( 5.0 / ( 4.0 * ( ( 1.0 - sigk ) ** 2 ) ) ) - ( 1.0 / ( 1.0 - sigk ) ) ) - 0.25 ) ) ) return xksq
tricomi initial guesses computes an initial approximation to the square of the k-th root :math:x_k of the hermite polynomial :math:h_n of order :math:n .