value value_drop(value op, value n)
{
if (op.type == VALUE_NIL) {
return value_init_nil();
} else if (op.type == VALUE_ARY) {
if (n.type == VALUE_MPZ) {
value length = value_set_long(op.core.u_a.length);
value res = value_range(op, n, length);
value_clear(&length);
return res;
}
} else if (op.type == VALUE_LST) {
if (n.type == VALUE_MPZ) {
if (value_lt(n, value_zero)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (>= 0 expected).", n);
return value_init_error();
} else if (value_gt(n, value_int_max)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (<= %s expected).", n, value_int_max);
return value_init_error();
}
size_t i, max = value_get_long(n);
value ptr = op;
for (i = 0; i < max && ptr.type == VALUE_LST; ++i) {
ptr = ptr.core.u_l[1];
}
return value_set(ptr);
}
} else if (op.type == VALUE_PAR) {
if (n.type == VALUE_MPZ) {
if (value_lt(n, value_zero)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (>= 0 expected).", n);
return value_init_error();
} else if (value_gt(n, value_int_max)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (<= %s expected).", n, value_int_max);
return value_init_error();
}
size_t i, max = value_get_long(n);
value ptr = op;
for (i = 0; i < max && ptr.type == VALUE_PAR; ++i) {
ptr = ptr.core.u_p->tail;
}
return value_set(ptr);
}
} else {
value_error(1, "Type Error: drop() is undefined where op1 is %ts (array or list expected).", op);
if (n.type == VALUE_MPZ)
return value_init_error();
}
value_error(1, "Type Error: drop() is undefined where op2 is %ts (integer expected).", n);
return value_init_error();
}
enum lp_result PL_polyhedron_opt(Polyhedron *P, Value *obj, Value denom,
enum lp_dir dir, Value *opt)
{
int i;
int first = 1;
Value val, d;
enum lp_result res = lp_empty;
POL_ENSURE_VERTICES(P);
if (emptyQ(P))
return res;
value_init(val);
value_init(d);
for (i = 0; i < P->NbRays; ++ i) {
Inner_Product(P->Ray[i]+1, obj, P->Dimension+1, &val);
if (value_zero_p(P->Ray[i][0]) && value_notzero_p(val)) {
res = lp_unbounded;
break;
}
if (value_zero_p(P->Ray[i][1+P->Dimension])) {
if ((dir == lp_min && value_neg_p(val)) ||
(dir == lp_max && value_pos_p(val))) {
res = lp_unbounded;
break;
}
} else {
res = lp_ok;
value_multiply(d, denom, P->Ray[i][1+P->Dimension]);
if (dir == lp_min)
mpz_cdiv_q(val, val, d);
else
mpz_fdiv_q(val, val, d);
if (first || (dir == lp_min ? value_lt(val, *opt) :
value_gt(val, *opt)))
value_assign(*opt, val);
first = 0;
}
}
value_clear(d);
value_clear(val);
return res;
}
value value_take(value op, value n)
{
if (op.type == VALUE_NIL) {
return value_init_nil();
} else if (op.type == VALUE_ARY) {
if (n.type == VALUE_MPZ) {
value start = value_set_long(0);
value res = value_range(op, start, n);
value_clear(&start);
return res;
}
} else if (op.type == VALUE_LST) {
if (n.type == VALUE_MPZ) {
if (value_lt(n, value_zero)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (>= 0 expected).", n);
return value_init_error();
} else if (value_gt(n, value_int_max)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (<= %s expected).", n, value_int_max);
return value_init_error();
}
value res = value_init_nil();
size_t i, max = value_get_long(n);
value ptr = op;
for (i = 0; i < max && ptr.type == VALUE_LST; ++i) {
value_cons_now(ptr.core.u_l[0], &res);
ptr = ptr.core.u_l[1];
}
value_reverse_now(&res);
return res;
}
} else if (op.type == VALUE_PAR) {
if (n.type == VALUE_MPZ) {
if (value_lt(n, value_zero)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (>= 0 expected).", n);
return value_init_error();
} else if (value_gt(n, value_int_max)) {
value_error(1, "Domain Error: drop() is undefined where n is %s (<= %s expected).", n, value_int_max);
return value_init_error();
}
value res = value_init_nil();
size_t i, max = value_get_long(n);
value ptr = op;
for (i = 0; i < max && ptr.type == VALUE_PAR; ++i) {
value_cons_now(ptr.core.u_p->tail, &res);
ptr = ptr.core.u_p->tail;
}
value_reverse_now(&res);
return res;
}
} else {
value_error(1, "Type Error: take() is undefined where op is %ts (array or list expected).", op);
if (n.type == VALUE_MPZ)
return value_init_error();
}
value_error(1, "Type Error: drop() is undefined where n is %ts (integer expected).", n);
return value_init_error();
}
