- Performs
- An index file input line looks like:
<ID> <incX> <source file> <author name>

- For complex, if both vectors have unit stride, the real routine is called
with
`2*N`. - The user should be aware that this routine was originally added to the BLAS
mostly for
*accuracy*concerns, not for optimization. The simple implementation of this routine:for (nrm2=0.0, i=0; i < N; i++, X += incX) nrm2 += *X * *X; return(sqrt(nrm2));

will needlessly overflow for half of the exponent range. Thus, a good implementation must either use extended precision or a scaling algorithm (such as the sum of squares used in the reference BLAS) to prevent overflow in the squaring process.

Clint Whaley 2012-07-10