about using math
about using math
Postby tinhaode » Wed Jan 31, 2018 10:16 am
I would like to use some of math related function calls like pow, sin, sqrt...
But it seems math function doesn't work with SDK.
Either #include<math.h> on user_main or -lm on the Linker doesn't work too.
Do you have any idea to work them out?
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Re: about using math
Postby AgentSmithers » Thu Feb 01, 2018 8:20 am
http://moishelettvin.blogspot.com/2005/ ... posed.html
Indirectly it may relate to your question.
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Re: about using math
Postby AgentSmithers » Fri Feb 09, 2018 12:37 am
tinhaode wrote:sorry I can't open the url. could you copy some word?
What math functions would you like, How fast do they need to be?
Functions like Sin I think is 1 = x^2 + y^2 so I think if you take an argument you just do 1 - (arg)^2 = Value then SquareRoot that I think. Sorry I took trig like a year ago and it's already gone XD
Re: about using math
Postby Pato » Sat Mar 24, 2018 1:02 am
@AgentSmithers: Indeed a kind of last resort solution would be to re-write the math functions (e.g. with Taylors series approximations, it's in the idea of what you proposed

@tinhaode: did you managed to fin a solution ? I'm also trying to experiment with math functions, but I got linker errors. Maybe try using the limirom.a from the RTOS_SDK, it seemed to work for some folks...
https://bbs.espressif.com/viewtopic.php ... math#p3215
(failed with same error for me. I use a custom toolchain inspired from esp-open-sdk)
Re: about using math
Postby Pato » Tue May 15, 2018 11:59 pm
https://bbs.espressif.com/viewtopic.php?f=7&t=9432
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about using math
Postby andreysnug » Fri May 25, 2018 2:12 pm
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