histogram

Elsewhere on StackOverflow a question was asked regarding a depthbuffer histogram - Create depth buffer histogram texture with GLSL . I am writing an iOS image-processing app and am intrigued by this question but unclear on the answer provided. So, is it possible to create an image histogram using the GPU via GLSL? Yes, it is. It's not clearly the best approach, but it's indeed the best one available in iOS, since OpenCL is not supported. You'll lose elegance, and your code will probably not as straightforward, but almost all OpenCL features can be achieved with shaders. If it helps, DirectX11

I need some guidance in working out how to plot a block of histograms from grouped data in a pandas dataframe. Here's an example to illustrate my question: from pandas import DataFrame import numpy as np x = ['A']*300 + ['B']*400 + ['C']*300 y = np.random.randn(1000) df = DataFrame({'Letter':x, 'N':y}) grouped = df.groupby('Letter') In my ignorance I tried this code command: df.groupby('Letter').hist() which failed with the error message "TypeError: cannot concatenate 'str' and 'float' objects" Any help most appreciated. dreme I'm on a roll, just found an even simpler way to do it using the by

I am trying to implement histogram in Neon. Is it possible to vectorise ? Histogramming is almost impossible to vectorize, unfortunately. You can probably optimise the scalar code somewhat however - a common trick is to use two histograms and then combine them at the end. This allows you to overlap loads/increments/stores and thereby bury some of the serial dependencies and associated latencies. Pseudo code: init histogram 1 to all 0s init histogram 2 to all 0s loop get input value 1 get input value 2 load count for value 1 from histogram 1 load count for value 2 from histogram 2 increment

I have count data (a 100 of them), each correspond to a bin (0 to 99). I need to plot these data as histogram. However, histogram count those data and does not plot correctly because my data is already binned. import random import matplotlib.pyplot as plt x = random.sample(range(1000), 100) xbins = [0, len(x)] #plt.hist(x, bins=xbins, color = 'blue') #Does not make the histogram correct. It counts the occurances of the individual counts. plt.plot(x) #plot works but I need this in histogram format plt.show() redrah If I'm understanding what you want to achieve correctly then the following