ToolPythonIntermediate Poisson's equation with scipy.sparse: two plates in a grounded box return sp.kron(D, I) + sp.kron(I, D)
ToolPythonIntermediate Sparse eigenvalues with scipy.sparse.linalg.eigsh: the tones of a drum return (-(sp.kron(D2, I) + sp.kron(I, D2))).tocsr()print("format of one kron:", sp.kron(D2, I).format, " of the sum:", (sp.kron(D2, I) + sp.kron(I, D2)).format)