mat4 inverse precision

[recp]

Hello,

Recently I have written a test to compare mat4 results in cglm repo (http://github.com/recp/cglm),
but I've precision problem, related test fails. What I'm trying to do is:

A = random matrix
B = inv(A)
C = inv(B)

assert(A == C)

I'm comparing float values via FLT_EPSILON (I guess it is 0.000001) but it doesn't seem to right value to compare?

I have tested the same with original glm but the result is same. Only this ( 0.0001) precision looks work :/

Test suite:

  ...
  glm::mat4 A = glm::make_mat4(cglm_matrix[0]);
  glm::mat4 B = glm::inverse(A);
  glm::mat4 C = glm::inverse(B);

  for (i = 0; i < m; i++) {
    for (j = 0; j < n; j++) {
      for (k = 0; k < m; k++) {
        /* fails  */
        assert(fabsf(A[i][j] - C[i][j]) <= FLT_EPSILON);

        /*
--------> this is always passing (on macos):
          assert(fabsf(A[i][j] - C[i][j]) <= 0.0001);
         */
      }
    }
  }
  ...

Any idea why the precision is too low (not FLT_EPSILON)? Or should I always use 0.0001 as epsilon to compare results?

[recp]

The random matrix was not an affine transform, now I tested with affine transform it looks good.

I'm closing this issue.