# FD logic doesn't always return all solutions

Given the following code

(run* [x11 x12 x13
x21 x22     x24
x31     x33 x34
x42 x43 x44]
(fd/in x11 x12 x13 x21 x22 x24 x31 x33 x34 x42 x43 x44 (fd/interval 1 9))
(fd/eq (= (+ x11 (/ x12 x13))   5)
(= (+ x21 (/ x22   2)) x24)
(= (+ x31 (/   6 x33)) x34)
(= (+   4 (/ x42 x43)) x44)
(= (+ x11 (/ x21 x31))   4)
(= (* x12 (/ x22   6)) x42)
(= (+ x13 (-   2 x33)) x43)
(= (+ (-  5 x24) x34)  x44)))

I have {{([1 4 1 3 6 6 1 1 7 4 2 6] [2 6 2 4 6 7 2 1 8 6 3 6])}} as a result.

However, as soon as I change {{(fd/interval 1 9)}} to {{(fd/interval 0 9)}}, the result becomes an empty sequence. However, I expect it to include at least the two aforementioned solutions.

by

It would help if you could confirm that the issue is present without using {{fd/eq}} - which is just macro sugar. Writing out the long form is tedious but it will help isolate the issue. Thanks.

by

I actually suspect that the bug is in `fd/eq`. Here is a smaller test case:

```
(run* [q]

``````  (fd/in q (fd/interval 1 2))
(fd/eq (= (/ q q) 1)))
``````

```

It returns `(1 2)` as expected, but as soon as I change `fd/interval` to `0 2`, it returns an empty seq.

by