1. A system for providing an interactive visualization of a convolutional neural network, the system comprising: a processing device; and a memory device on which instructions executable by the processing device are stored for causing the processing device to: display, via a display device, a graphical user interface comprising a matrix having rows and columns of symbols indicating feature-map values that represent likelihoods of particular features being present or absent at various locations in an input to a convolutional neural network, each column in the matrix having feature-map values generated by convolving the input to the convolutional neural network with a respective filter for identifying a particular feature in the input; detect, via an input device, an interaction with the graphical user interface indicating that the columns in the matrix are to be combined into a particular number of groups; and in response to detecting the interaction: cluster the columns into the particular number of groups using a clustering method; for each group of columns, determine a plurality of average feature-map values, each average feature-map value being determined by averaging the feature-map values represented in a respective row of the columns; and display an updated version of the matrix within the graphical user interface by visually representing each respective group of columns as a single column of symbols within the matrix, each symbol in the single column of symbols having visual characteristics representing an average feature-map value, from among the plurality of average feature-map values, that corresponds to a row in which the symbol is positioned.