FUNCTION :  newxy - Compute new x,y mod N                            

CALLING SEQUENCE :  newxy()                                             
                    newxy(x,y,N)                                             

PARAMETERS :    x,y,N - integers such that N > 0 and (x,y,N)=1

SYNOPSIS :   Suppose (x,y,N)=1. This proc returns [x1,y1] such     
             (x1,y1)=1, x1 == x mod N and y1 == y mod N.             
             This function is used by cuspmake1. 

EXAMPLES :   

> with(thetaids):

> newxy();
---------------------------------------------------------
newxy(x,y,N)                                             
   Suppose (x,y,N)=1. This proc returns [x1,y1] such     
   (x1,y1), x1 == x mod N and y1 == y mod N.             
---------------------------------------------------------
> newxy(2,4,9);
                                     [2, 13]

DISCUSSION :  We see (2,13)=1 and 13==4 mod 9. 

SEE ALSO : cuspmake1