def __get_blob_dimensions(self, chunk_dim):
<EOL>if self.selection_shape[self.freq_axis] > chunk_dim[self.freq_axis]*MAX_BLOB_MB:<EOL><INDENT>freq_axis_size = self.selection_shape[self.freq_axis]<EOL><INDENT>while freq_axis_size > chunk_dim[self.freq_axis]*MAX_BLOB_MB:<EOL><INDENT>freq_axis_size /= <NUM_LIT:2><EOL><DEDENT><DEDENT>time_axis_size = <NUM_LIT:1><EOL><DEDENT>else:<EOL><INDENT>freq_axis_size = self.selection_shape[self.freq_axis]<EOL>time_axis_size = np.min([chunk_dim[self.time_axis] * MAX_BLOB_MB * chunk_dim[self.freq_axis] / freq_axis_size, self.selection_shape[self.time_axis]])<EOL><DEDENT>blob_dim = (int(time_axis_size), <NUM_LIT:1>, freq_axis_size)<EOL>return blob_dim<EOL>
Sets the blob dimmentions, trying to read around 1024 MiB at a time.
            This is assuming a chunk is about 1 MiB.