Hi, In MKL documentaion (http://software.intel.com/sites/products/documentation/hpc/mkl/mklman/GUID-78250DC6-6203-42B5-B46E-638CE1BC5D88.htm#TBL17-8), 'Boundary Conditions Supported by Data Fitting Functions' says 'DF_BC_1ST_LEFT_DER' is 'The first derivative at the left endpoint is zero.'. Then what does this 'is zero' mean ?
I actually tried NATURAL spline with DF_BC_1ST_LEFT_DER|DF_BC_1ST_RIGHT_DER options(etc),and got different results for non zero boundary values.
I also tried LINEAR spline with/without PERIODIC option, and it showed no difference even in the region outside of specified x-range.
# I got these results from 'Math Kernel Library Version 10.3.11 Product Build 20120606 for 32-bit applications' on Windows 7.