1536	 Dynamic Computation of Derivatives	 It is shown how Wengert s procedure for computation of derivatives can be implemented conveniently by use of compiler-generated complex addition subtraction and linkage to complex arithmetic subroutines. Evaluation of a function and derivative proceed in parallel as in Wengert s procedure but with the imaginary parts of variables declared complex bearing the values of the derivatives of the real parts. This technique provides a simple way to compute the derivatives of a function without the need for deriving and programming the evaluation of explicit formulas for the derivatives.
