You can skip the next section if you want, but linear systems and Gaussians are so friendly that Dr. For the sake of higher performance the index range checks are only performed in Debug conguration. This particular version is for accessing a one-dimensional array. Here, the usual screen coordinate system is assumed - the origin is at the top-left corner, x axis is oriented to the right, and y axis is oriented downwards. Its up to the user to detect such elements and delete them using SparseMat::erase.
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