Avoid mixing integer and floating-point (REAL) data in the same computation. Expressing all numbers in a floating-point arithmetic expression (assignment statement) as floating-point values eliminates the need to convert data between fixed and floating-point formats. Expressing all numbers in an integer arithmetic expression as integer values also achieves this. This improves run-time performance.
For example, assuming that I and J are both INTEGER variables, expressing a constant number (2.) as an integer value (2) eliminates the need to convert the data:
| Original Code: | INTEGER I, J
I= J / 2. |
| Efficient Code: | INTEGER I, J
I= J / 2 |
For applications with numerous floating-point operations, consider using the /assume: accuracy_sensitive option (see Arithmetic Reordering Optimizations) if a small difference in the result is acceptable.
You can use different sizes of the same general data type in an expression with minimal or no effect on run-time performance. For example, using REAL, DOUBLE PRECISION, and COMPLEX floating-point numbers in the same floating-point arithmetic expression has minimal or no effect on run-time performance.