IAMAX[x]
gives the position of the element with the maximum absolute value in a vector x.


IAMAX
IAMAX[x]
gives the position of the element with the maximum absolute value in a vector x.
Details and Options
- To use IAMAX, you first need to load the BLAS Package using Needs["LinearAlgebra`BLAS`"].
- The following argument must be given:
-
x input expression vector - For complex vectors x, IAMAX locates the element with the greatest sum of absolute values of the real and imaginary parts.
- If x contains non-numeric elements, then IAMAX[x] always returns $Failed.
- For duplicate entries the first position found is returned.
Examples
open all close allBasic Examples (1)
Scope (4)
An arbitrary-precision vector:
Vectors with symbolic entries will return $Failed:
Properties & Relations (1)
Possible Issues (2)
If there are multiple elements with the same maximum absolute value, the position of the first one is returned:
If a vector contains a symbol, IAMAX returns $Failed:
Related Guides
Text
Wolfram Research (2017), IAMAX, Wolfram Language function, https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/IAMAX.html.
CMS
Wolfram Language. 2017. "IAMAX." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/IAMAX.html.
APA
Wolfram Language. (2017). IAMAX. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/IAMAX.html
BibTeX
@misc{reference.wolfram_2025_iamax, author="Wolfram Research", title="{IAMAX}", year="2017", howpublished="\url{https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/IAMAX.html}", note=[Accessed: 04-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_iamax, organization={Wolfram Research}, title={IAMAX}, year={2017}, url={https://reference.wolfram.com/language/LowLevelLinearAlgebra/ref/IAMAX.html}, note=[Accessed: 04-August-2025]}