How to construct a division constraint

[Ranganhar Guo]

Now I have an isl_map, which prints out as follows: { S_7[k, i, j] -> C[o0, o1] }.
I want to construct a constraint that ideally should look like this: {S_7[k, i, j] -> C[o0, o1]: i / j = o0}.
How can I use isl_val / isl_aff / isl_constraint to construct this constraint?
 
I tried using isl_aff_var_on_domain to perform arithmetic operations between isl_aff variables, but when using isl_div, the second operand must be a constant, which seems unfeasible. Are there any other methods (besides reading from a string)?

Thanks for your help.

Below is my code implementation.

int lhs_pos = comp->get_loop_level_number_from_dimension_name(lhs.get_name());

int rhs_pos = comp->get_loop_level_number_from_dimension_name(rhs.get_name());

auto sp = isl_map_get_space(map);

isl_local_space *ls = isl_local_space_from_space(sp);

isl_aff* lhs_var = isl_aff_var_on_domain(isl_local_space_copy(ls), isl_dim_in, lhs_pos);

isl_aff* rhs_var = isl_aff_var_on_domain(isl_local_space_copy(ls), isl_dim_in, rhs_pos);

isl_aff* out_var = isl_aff_var_on_domain(isl_local_space_copy(ls), isl_dim_out, i);

isl_aff* result = isl_aff_mul(lhs_var, rhs_var);

result = isl_aff_sub(result, out_var);

cst = isl_equality_from_aff(result);

map = isl_map_add_constraint(map, cst);

[Sven Verdoolaege]

On Mon, Jun 16, 2025 at 07:30:14PM -0700, Ranganhar Guo wrote:
> Now I have an isl_map, which prints out as follows: { S_7[k, i, j] -> C[o0,
> o1] }.
> I want to construct a constraint that ideally should look like this:
> {S_7[k, i, j] -> C[o0, o1]: i / j = o0}.
> How can I use isl_val / isl_aff / isl_constraint to construct this
> constraint?

This is a non-affine constraint, so you can't represent it in isl.

skimo