Developer Reference

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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(
x
[
i
])|+|Im(
x
[
i
])|
for complex flavors.
index of the element with the smallest absolute value for real flavors, or the smallest sum
|Re(
x
[
i
])|+|Im(
x
[
i
])|
for complex flavors.
The result
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]
; the corresponding index in full-storage array is
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
.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.