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

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804