# Piecewise linear approximation
# Oscar Gustafsson, address@hidden

param inputbits := 12;
param partitionbits := 5;
param coeffbits := 12;

set Y := {0..(2^partitionbits-1)};
set Z := {0..(2^(inputbits-partitionbits)-1)};
param X{y in Y, z in Z} := (2^(inputbits-partitionbits)*y + z)/2^inputbits;

var p{y in Y} integer;
var q{y in Y} integer;

var error>=0;


s.t. postive{y in Y, z in Z}: (p[y] + z*q[y]/2^(inputbits))/2^coeffbits - cos(X[y,z]) <= error;

s.t. negative{y in Y, z in Z}: -((p[y] + z*q[y]/2^(inputbits))/2^coeffbits - cos(X[y,z])) <= error;

minimize e: error;
solve;

printf "p = [" ;
for {y in Y} 
{
	printf " %d", p[y] ;
}
printf("];\n");
printf("q = [");
for {y in Y} 
{
	printf "%d ", q[y];
}
printf("];\n");
end;