Efficient algorithm for online Variance over image batches Question: I have a large amount of images and want to calculate the variance (of each channel) across all of them. I’m having problem finding an efficient algorithm / setup for that. I read on of the Welford’s online algorithm but it is way to slow as …
Calculate the mean and variance by element by element of multiple arrays in Python Question: I have a block of code that provides five arrays: for i in range(10): x = pic[10,15+i] This produces the following ten arrays: [504 591 471 … 0 0 0] [748 753 658 … 94 138 101] [814 781 710 …
calculate aggregated variance for each group in python Question: I have a data frame (df) with these columns: user, vector, and group. df = pd.DataFrame({‘user’: [‘user_1’, ‘user_2’, ‘user_3’, ‘user_4’, ‘user_5’, ‘user_6’], ‘vector’: [[1, 0, 2, 0], [1, 8, 0, 2],[6, 2, 0, 0], [5, 0, 2, 2], [3, 8, 0, 0],[6, 0, 0, 2]], ‘group’: …
How can I calculate the variance of a list in python? Question: If I have a list like this: results=[-14.82381293, -0.29423447, -13.56067979, -1.6288903, -0.31632439, 0.53459687, -1.34069996, -1.61042692, -4.03220519, -0.24332097] I want to calculate the variance of this list in Python which is the average of the squared differences from the mean. How can I go …
variance vs coefficient of variation Question: I need to identify which statistic let me to find on digital image which line has the highest variation. I am using Variance (square units, calculated as numpy.var(x)) and Coefficient of Variation (unitless, calculated as numpy.sd(x)/numpy.mean(x)), but I got different values, as here: v1 = line(VAR(x)) v2 = line(CV(x)) …
Python: Variance of a list of defined numbers Question: I am trying to make a function that prints the variance of a list of defined numbers: grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5] So far, I have tried proceeding on making these three functions: def grades_sum(my_list): total …
