Hi,
I'm aware that this question is close to that being asked in: https://software.intel.com/en-us/forums/intel-math-kernel-library/topic/...
I'm using an older version of MKL, version 11.0.5, and I am having problems with the use of the Akima cubic spline that I can't find any concrete answer for in the documentation.
I'm using a combination of boundary conditions on the spline, depending on the case, of either a fixed value to the 1st or 2nd derivative at the left and right edge (both left and right BC are always defined). I don't define any internal conditions, and I use a non-uniform partition for the x breakpoints.
The problem I am encountering is that if there is <= 4 breakpoints, the dfdConstruct1D method will fail with the error 'Error: the number of breakpoints is invalid (code -1004).' At the moment, the code will enforce a linear interpolation of there are <= 2 breakpoints which I understood to be the minimum.
However, I can't seem to find anywhere in the documentation that the minimum number of breakpoints required for each cubic spline method is defined.
Can someone clarify what the minimum number of breakpoints required is for each of the methods, and how the BC's and/or IC's change this behaviour?
Thanks,
Ewan