title: Dimension reduction Using PCA while preserving variance in percentage
body: <p>i am  trying to reduce the dimensions of MNIST dataset using PCA. Trick is, i have to preserve the certain percentage of variance(say 80%) while reducing the dimension. I am using Scikit learn. I am doing pca.get_variance <em>ratio</em> but it gives me same values with different dot location like 9.7 or .97 or .097. i am also tried pca.get_variance() but i assume that's not the answer. My question is how to ensure that i have reduce the dimension with certain variance percentage preserve?</p>