Averaging 'blocks' of data
I'm not sure I exactly understand your problem, but if you are looking for a recursive algorithm for calculating the average by addition of one record only at a time, consider: y[k] = y[k-1] + (x[k] - y[k-1])/k, where y(0) = 0, k = 1, 2, ... At each stage, y[k] = (x[1]+...+x[k])/k.
At 04:46 PM 9/7/2008, Steve Murray wrote:
Gabor - thanks for your suggestion... I had checked the previous post, but I found (as a new user of R) this approach to be too complicated and I had problems gaining the correct output values. If there is a simpler way of doing this, then please feel free to let me know. Dylan - thanks, your approach is a good start. In answer to your questions, my data are 43200 columns and 16800 rows as a data frame - I will probably have to read the dataset in segments though, as it won't fit into the memory! I've been able to follow your example - how would I be able to apply this technique for finding the average of each 60 x 60 block? Any other suggestions are of course welcome! Many thanks again, Steve
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