GEMV[ts,α,a,x,β,y]
computes the matrix-vector multiplication α opts[a].x +β y and resets y to the result.
GEMV
GEMV[ts,α,a,x,β,y]
computes the matrix-vector multiplication α opts[a].x +β y and resets y to the result.
Details and Options
- To use GEMV, you first need to load the BLAS Package using Needs ["LinearAlgebra`BLAS`"].
- The following arguments must be given:
-
ts input string transposition stringα input expression scalar mutliplea input expression rectangular matrixx input expression vectorβ input expression scalar multipley input/output symbol vector; the symbol value is modified in place
- The transposition string ts describes the operator opts and may be specified as:
-
"N" no transposition"T" transpose"C" conjugate transpose
- Dimensions of the matrix and vector arguments must be such that the dot product and addition are well defined.
Examples
open all close allBasic Examples (1)
Load the BLAS package:
Compute a.x+2 y and save it in y:
Scope (4)
Real matrix and vectors:
Complex matrix and vectors:
Arbitrary-precision matrix and vectors:
Symbolic matrix and vectors:
Properties & Relations (3)
GEMV["N",α,a,x,β,y] is equivalent to y=α a.x+β y:
GEMV["T",α,a,x,β,y] is equivalent to y=α Transpose[a].x+β y:
GEMV["C",α,a,x,β,y] is equivalent to y=α ConjugateTranspose[a].x+β y:
Possible Issues (2)
The last argument must be a symbol:
If the last argument is not a symbol initialized to a vector then an error message is issued:
Related Guides
Text
Wolfram Research (2017), GEMV, Wolfram Language function, https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/GEMV.html.
CMS
Wolfram Language. 2017. "GEMV." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/GEMV.html.
APA
Wolfram Language. (2017). GEMV. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/GEMV.html
BibTeX
@misc{reference.wolfram_2025_gemv, author="Wolfram Research", title="{GEMV}", year="2017", howpublished="\url{https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/GEMV.html}", note=[Accessed: 16-November-2025]}
BibLaTeX
@online{reference.wolfram_2025_gemv, organization={Wolfram Research}, title={GEMV}, year={2017}, url={https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/GEMV.html}, note=[Accessed: 16-November-2025]}