21 lines
498 B
R
21 lines
498 B
R
# compute the mean of the columns and the rows of a matrix
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library(foreach)
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# generate the input matrix
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x <- matrix(rnorm(100 * 100), 100)
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# compute the mean of each column of x
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cmeans <- foreach(i=1:ncol(x), .combine=c) %do% mean(x[,i])
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# check the results
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expected <- colMeans(x)
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print(all.equal(cmeans, expected))
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# compute the mean of each row of x
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rmeans <- foreach(i=1:nrow(x), .combine=c) %do% mean(x[i,])
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# check the results
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expected <- rowMeans(x)
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print(all.equal(rmeans, expected))
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