nx

=n_elements(x) − 1

na

=n_elements(a) − 1

y0

=replicate (0., nx + 1)

y1

=replicate (0., nx + 1)

y2

=replicate (0., nx + 1)

y3

=replicate (0., nx + 1)

y4

=replicate (0., nx + 1)

case label of

……

k: begin

……

goto, ret

end

……

endcase

ret: struct = create_struct('fit function label', label, $

'fit constants', a,'fit parameters, b,'variable', x,$

'y(T) at x', y0,'dy/dT', y1,'d²y/dT²', y2, $

'd³y/dT³', y3,'integral y(T) dT', y4)

return, struct

END