diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/proj_4D_api.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/src/proj_4D_api.c b/src/proj_4D_api.c index fa24c430..6654522c 100644 --- a/src/proj_4D_api.c +++ b/src/proj_4D_api.c @@ -100,7 +100,7 @@ double proj_xyz_dist (XYZ a, XYZ b) { /* Measure numerical deviation after n roundtrips fwd-inv (or inv-fwd) */ double proj_roundtrip (PJ *P, PJ_DIRECTION direction, int n, PJ_COORD *coo) { int i; - PJ_COORD o, u, org; + PJ_COORD t, org; if (0==P) return HUGE_VAL; @@ -111,23 +111,23 @@ double proj_roundtrip (PJ *P, PJ_DIRECTION direction, int n, PJ_COORD *coo) { } /* in the first half-step, we generate the output value */ - u = org = *coo; - o = *coo = proj_trans (P, direction, u); + org = *coo; + *coo = proj_trans (P, direction, org); + t = *coo; - /* now we take n-1 full steps */ - for (i = 0; i < n - 1; i++) { - u = proj_trans (P, -direction, o); - o = proj_trans (P, direction, u); - } + /* now we take n-1 full steps in inverse direction: We are */ + /* out of phase due to the half step already taken */ + for (i = 0; i < n - 1; i++) + t = proj_trans (P, direction, proj_trans (P, -direction, t) ); /* finally, we take the last half-step */ - u = proj_trans (P, -direction, o); + t = proj_trans (P, -direction, t); /* checking for angular *input* since we do a roundtrip, and end where we begin */ if (proj_angular_input (P, direction)) - return proj_lpz_dist (P, org.lpz, u.lpz); + return proj_lpz_dist (P, org.lpz, t.lpz); - return proj_xyz_dist (org.xyz, u.xyz); + return proj_xyz_dist (org.xyz, t.xyz); } |