invmod (4) --- find inverse of an integer modulo another integer  07/20/84


          | _C_a_l_l_i_n_g _I_n_f_o_r_m_a_t_i_o_n

                 long_int function invmod (x1, x0)
                 long_int x1, x0

          |      Library: vswtmath (Subsystem mathematical library)


            _F_u_n_c_t_i_o_n

                 'Invmod'  is used to find the inverse of 'x1' in the ring of
                 integers modulo 'x0'.  The function return is the inverse if
                 it could  be  found,  or  ERR  if  'x1'  and  'x0'  are  not
                 relatively prime.


            _I_m_p_l_e_m_e_n_t_a_t_i_o_n

                 'Invmod'  uses a variant of Euclid's greatest common divisor
                 algorithm.


            _B_u_g_s

                 Rational behavior for nonpositive  arguments  has  not  been
                 established.

                 Locally supported.


            _S_e_e _A_l_s_o

                 gcd (4)

























            invmod (4)                    - 1 -                    invmod (4)