AnsweredAssumed Answered

Standarddeviation using DSPLib returns 0

Question asked by dohr.martin.001 on Aug 19, 2015
Latest reply on Aug 20, 2015 by dohr.martin.001
Hi,

I have encountered the following problem on the STM32F4 using the CMSIS DSP Library V1.4.2:

When calculating the standard deviation using arm_std_f32() of the following values
        </colgroup>                                                                                                                                                                                                                                                                                                the result is 0. This has been verified using the CM4 implementation with FPU. Also, quite often I get results of exactly 2.0 or 4.0 which is very unlikely as my input values are noisy.
Can someone reproduce this behavior? Am I running into the limits of single precision floats?

thanks, Martin
7111.15283
7111.38672
7111.40527
7111.50684
7111.59375
7112.03369
7112.12793
7112.1416
7112.68164
7113.02783

Outcomes