topic Re: Can eval evaluate Cosines? in Splunk Search

Can eval evaluate Cosines?

davecroto — Thu, 16 Jun 2011 12:49:01 GMT

Can eval evaluate Cosines?

Re: Can eval evaluate Cosines?

Ayn — Thu, 16 Jun 2011 14:00:26 GMT

No, it cannot.

A complete list of commands supported by eval is available here: http://www.splunk.com/base/Documentation/latest/SearchReference/CommonEvalFunctions

Re: Can eval evaluate Cosines?

dwaddle — Thu, 16 Jun 2011 15:15:25 GMT

This could be a good candidate for a custom search command. See http://www.splunk.com/base/Documentation/latest/SearchReference/Aboutcustomsearchcommands for info on how to roll your own.

Something else to consider is filing an ER (Enhancement request) for either providing additional mathematical functions in eval (If you're going to do cosine -- you might as well do sine, secant, and tangent) or providing a way to create user-defined eval functions. (Assuming, of course, that the API for an eval UDF would have any benefit at all over a custom search command. I am not certain if this is the case or not)

Re: Can eval evaluate Cosines?

sdorich — Mon, 28 Sep 2020 15:49:19 GMT

Approximate functions like cosine or sine using its Taylor series!

http://www.math.sc.edu/~girardi/m142/handouts/10sTaylorPolySeries.pdf

Write a stanza in macros.conf that defines cosine as an approximation using its Taylor series.

Ex:

[cosine(1)]
args=x
description = calculates an approximate value for cosine of x
definition = eval cosineX=(1 - ((x*x)/2) + ((x*x*x*x)/(4*3*2)) - ....)

And add as many terms as you'd like - as you add more terms your approximation of cosine of x will start to converge to the actual value.

Re: Can eval evaluate Cosines?

sdorich — Thu, 06 Feb 2014 22:32:51 GMT

I forgot to add money signs around all the x terms in the definition above - each x should be surrounded (i.e. $x$*$x$...)

Re: Can eval evaluate Cosines?

sdorich — Thu, 06 Feb 2014 22:35:23 GMT

By the way, I haven't actually tried this so my above answer may need some tweaking.

Re: Can eval evaluate Cosines?

aljohnson_splun — Thu, 21 Jul 2016 22:01:23 GMT

Basic trigonometric eval functions got added in 6.4.

http://docs.splunk.com/Documentation/Splunk/latest/SearchReference/CommonEvalFunctions#Trigonometry_and_Hyperbolic_functions