/usr/include/ is in libeinspline-dev 0.9.2-2.
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..
/usr/include/einspline/
/usr/include/einspline/bspline_eval_cuda.h
/usr/include/einspline/bspline_create.h
/usr/include/einspline/bspline_eval_sse_d.h
/usr/include/einspline/multi_bspline_eval_z.h
/usr/include/einspline/multi_nubspline_create.h
/usr/include/einspline/multi_bspline_structs_cuda.h
/usr/include/einspline/multi_nubspline_eval_d.h
/usr/include/einspline/nubspline_eval_std_s.h
/usr/include/einspline/nubspline_eval_sse_d.h
/usr/include/einspline/nubasis.h
/usr/include/einspline/multi_bspline_eval_d.h
/usr/include/einspline/multi_bspline_eval_c.h
/usr/include/einspline/bspline_eval_std_d.h
/usr/include/einspline/bspline_eval_sse_s.h
/usr/include/einspline/multi_bspline_create_cuda.h
/usr/include/einspline/multi_nubspline.h
/usr/include/einspline/nubspline_eval_std_d.h
/usr/include/einspline/multi_nubspline_eval_c.h
/usr/include/einspline/nugrid.h
/usr/include/einspline/bspline.h
/usr/include/einspline/bspline_eval_std_s.h
/usr/include/einspline/multi_bspline_create.h
/usr/include/einspline/multi_nubspline_eval_s.h
/usr/include/einspline/multi_bspline_eval_s.h
/usr/include/einspline/multi_bspline.h
/usr/include/einspline/bspline_eval_sse_c.h
/usr/include/einspline/bspline_create_cuda.h
/usr/include/einspline/fbspline.h
/usr/include/einspline/bspline_structs.h
/usr/include/einspline/nubspline_structs.h
/usr/include/einspline/multi_nubspline_eval_z.h
/usr/include/einspline/fmulti_bspline.h
/usr/include/einspline/multi_bspline_eval_cuda.h
/usr/include/einspline/nubspline_eval_sse_c.h
/usr/include/einspline/bspline_eval_std_c.h
/usr/include/einspline/multi_nubspline_structs.h
/usr/include/einspline/nubspline_base.h
/usr/include/einspline/multi_bspline_structs.h
/usr/include/einspline/nubspline_eval_sse_z.h
/usr/include/einspline/bspline_base.h
/usr/include/einspline/nubspline_create.h
/usr/include/einspline/bspline_eval_sse_z.h
/usr/include/einspline/bspline_structs_cuda.h
/usr/include/einspline/fnubspline.h
/usr/include/einspline/bspline_eval_std_z.h
/usr/include/einspline/nubspline_eval_sse_s.h
/usr/include/einspline/nubspline_eval_std_z.h
/usr/include/einspline/config.h
/usr/include/einspline/nubspline.h
/usr/include/einspline/nubspline_eval_std_c.h