# mxnet.test_utils.var_check¶

mxnet.test_utils.var_check(generator, sigma, nsamples=1000000)[source]

Test the generator by matching the variance. It will need a large number of samples and is not recommended to use

We test the sample variance by checking if it falls inside the range

(sigma^2 - 3 * sqrt(2 * sigma^4 / (n-1)), sigma^2 + 3 * sqrt(2 * sigma^4 / (n-1)))

References:

@incollection{goucher2009beautiful,
title={Beautiful Testing: Leading Professionals Reveal How They Improve Software},
author={Goucher, Adam and Riley, Tim},
year={2009},
chapter=10
}


Examples:

generator = lambda x: np.random.normal(0, 1.0, size=x)
var_check_ret = var_check(generator, 0, 1.0)

Parameters
• generator (function) – The generator function. It’s expected to generate N i.i.d samples by calling generator(N).

• sigma (float) –

• nsamples (int) –

Returns

ret – Whether the variance test succeeds

Return type

bool