BLAS Level 1 Routines That Can Work With Sparse Vectors
The following BLAS Level 1 routines will give correct results when you pass to them a compressed-form array
:
x
(with the increment
incx
=1)- sum of absolute values of vector elements
- copying a vector
- Euclidean norm of a vector
- scaling a vector
- index of the element with the largest absolute value for real flavors, or the largest sum|Re(for complex flavors.x[i])|+|Im(x[i])|
- index of the element with the smallest absolute value for real flavors, or the smallest sum|Re(for complex flavors.x[i])|+|Im(x[i])|
The result
; the corresponding index in full-storage array is
.
i
returned by
i?amax
and
i?amin
should be interpreted as index in the compressed-form array, so that the largest (smallest) value is
x
[i
-1]indx
[i
-1]You can also call
cblas_?rotg
to compute the parameters of Givens rotation and then pass these parameters to the Sparse BLAS routines
cblas_?roti
.