use to solve this equation it will take too long and so what they did here was they used one of those solvers known PDE solvers to kind of solve those equations on kind of small domains small four-dimensional domains right because it's three dimensions of space and one dimensional time and they train a convolutional net to produce the same result but that convolutional net has a bigger grid right so a PDE solver basically takes one value when vauxhall okay four dimensional voxel if you want or 3-dimensional Vauxhall and then looks