On 2010-08-10 04:32, Frank Barknecht wrote:
Hi,
I made two generators for Gaussian white noise, one using DSP, the other as message based version. Both use the same algorithm, but the histogram analysis of both shows a defect with the message version: The histogram has a visible "valley" around the central expectation value, so it doesn't look like a real gaussian bell curve anymore.
The message version is based on [random] not [noise~], and I "faked" a true frand by taking and scaling random values from the range 0-100000. Could this be the reason for the valleys or is the reason the custom algorithm [random] uses or is it, that two [random]s are not sufficiently independent?
Yes it is the reason for the valleys. Your random is on [-0.5,0.5] instead of [-1,1]. The random needs to be multiplied by 2 million before subtracting one million then dividing by one million. Then it works. Also an uncertain execution order in the log divide part needs one of those [tff]s. The DSP version looks normal to me if I sample it a few times.
Martin