标准偏差方程
Result = sqrt((sumOfSquares - sum<sup>2</sup> / blockSize) / (blockSize - 1))
sumOfSquares = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]
sum = pSrc[0] + pSrc[1] + pSrc[2] + ... + pSrc[blockSize-1]
这里sum<sup>2</sup>是表示sum^2 |