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# scipy.sparse.bmat

`scipy.sparse.``bmat`(blocks, format=None, dtype=None)

  Build a sparse matrix from sparse sub-blocks

  Parameters : | blocks : array_like Grid of sparse matrices with compatible shapes. An entry of None implies an all-zero matrix. format : {‘bsr’, ‘coo’, ‘csc’, ‘csr’, ‘dia’, ‘dok’, ‘lil’}, optional The sparse format of the result (e.g. “csr”). If not given, the matrix is returned in “coo” format. dtype : dtype specifier, optional The data-type of the output matrix. If not given, the dtype is determined from that of blocks.
  Returns : | bmat : sparse matrix A “coo” sparse matrix or type of sparse matrix identified by format.

  See also

  `block_diag`, `diags`

  Examples

      >>> from scipy.sparse import coo_matrix, bmat
      >>> A = coo_matrix([[1,2],[3,4]])
      >>> B = coo_matrix([[5],[6]])
      >>> C = coo_matrix([[7]])
      >>> bmat( [[A,B],[None,C]] ).todense()
      matrix([[1, 2, 5],
              [3, 4, 6],
              [0, 0, 7]])

      >>> bmat( [[A,None],[None,C]] ).todense()
      matrix([[1, 2, 0],
              [3, 4, 0],
              [0, 0, 7]])

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