PRO gfunct, $
; inputs:
X, $ ; independent variable
A, $ ; coefficients
; outputs :
F, $ ; dependent variable
pder ; partial derivatives

F = A[0] * EXP(A[1] * X) + A[2]
pder = [[EXP(A[1] * X)], [A[0] * X * EXP(A[1] * X)], [replicate(1.0, N_ELEMENTS(X))]]

END