bugGNU Scientific Library - Bugs: bug #52351, akima.c array indexing


You are not allowed to post comments on this tracker with your current authentication level.

bug #52351: akima.c array indexing

Submitter:  Patrick Alken <psa>
Submitted:  Mon 06 Nov 2017 01:51:04 PM UTC
Category:  Runtime error Severity:  3 - Normal
Operating System:  Status:  None
Assigned to:  None Open/Closed:  Open

Mon 06 Nov 2017 01:51:04 PM UTC, original submission:  

from th =dot= walter42 =at= gmx =dot= de

On the other hand, I think I found the root cause of the misbehavior of the akima algorithm.
It is located in function akima_calc() in the block

if (NE_next == 0.0)
              tL_ip1 = m[i+1]; /* here '+1' was missing; because after adding, the graph looks much better */

All variables related to the next with indices have a '+1' except 'tl_ip1'.
Replacing 'm[i]' by 'm[i+1]' results in a smooth spline curve.


sorry for not being exact enough.
I refer to the demo2.c example living in the sub-directory "interpolation".
If the plotutils are available then visualization can be done via

    ./demo2 | graph -T X

With Kind Regards,

Patrick Alken <psa>
Group administrator


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

No files currently attached


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by psa (Submitted the item)

    No changes have been made to this item

    Back to the top

    Powered by Savane 3.13-b921.
    Corresponding source code