Before you modify source code to avoid slow arithmetic operators, be aware that optimizations convert many slow arithmetic operators to faster arithmetic operators. For example, the compiler optimizes the expression H=J**2 to be H=J*J.
Consider also whether replacing a slow arithmetic operator with a faster arithmetic operator will change the accuracy of the results or impact the maintainability (readability) of the source code.
Replacing slow arithmetic operators with faster ones should be reserved for critical code areas. The following hierarchy lists the Compaq Fortran arithmetic operators, from fastest to slowest: