HvD: Adding the Heaviside function trick to deal with piecewise defined functions. This simply requires specifying that the derivatives of the Heaviside function are zero, and adding the appropriate function declarations to the generated Fortran code.  Also, one partial derivative was missed out. I have added that one as well.
HvD: Adding the Heaviside function trick to deal with piecewise defined
functions. This simply requires specifying that the derivatives of the
Heaviside function are zero, and adding the appropriate function declarations
to the generated Fortran code. 
Also, one partial derivative was missed out. I have added that one as well.





rangsimanketkaew/NWChem