Restructuring the BLAS Level 1 Routine for Computing the Modified Givens Transformation

We look at how both logical restructuring and improvements available from successive versions of Fortran allow us to reduce the complexity (measured by a number of the commonly used software metrics) of the Level 1 BLAS code used to compute the modified Givens transformation. With these reductions in complexity we claim that we have improved both the maintainability and clarity of the code; in addition, we report a fix to a minor problem with the original code. The performance of two commercial Fortran restructuring tools is also reported.