/*
Copyright © 2026 filifa

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package lib

func DirichletConvolve(a, b []complex128) []complex128 {
	c := make([]complex128, min(len(a), len(b)))
	for i, x := range a {
		for j, y := range b {
			if i*j >= len(c) {
				break
			}

			c[i*j] += x * y
		}
	}

	return c
}