topic Hello, in Intel® Integrated Performance Primitives

Standard deviation in MeanStdDev doesn't return the result according to the documentation

Duverney-Prêt__Pierr — Tue, 24 Dec 2019 14:51:50 GMT

Hello,

It seems than the MeanStdDev function doesn't calculate the standard deviation following the documentation. After doing a simple test I noticed that the result value is divided by the length of the imput vector and not "length - 1" as it was written on the documentation.

I used the following vector for my test: vec[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

I'm using IPP version 2019.0.5

Is it a known issue?

Hello,

Gennady_F_Intel — Wed, 25 Dec 2019 08:09:00 GMT

Hello,

the quick checking with the current ( latest) IPP 2020 shown the following results with ippsMeanStdDev_64f function.

>_tese.exe
========================================================================
version of IPP is: ippIP AVX2 (l9) 2020.0.0 Gold (r0x0f66e7e3) 2020.0.0.258402275
========================================================================
... ippsMeanStdDev_64f PASSED ...
...Mean == 4.500000, ... StdDev == 3.027650 ...
Do you see the same outputs?

-Gennady

My outputs are: Mean = 4

Duverney-Prêt__Pierr — Thu, 02 Jan 2020 08:18:35 GMT

My outputs are: Mean = 4.500000, StdDev = 2.8722813232690143 .

I'm expected the same outputs as yours so I will update my version.

Thanks for your help =)

Cheers,

Pierre