# Sparse : Python basic dictionary sparse matrix

# Copyright (c) 2007, Stuart Mitchell (s.mitchell@auckland.ac.nz)
# $Id: sparse.py 1704 2007-12-20 21:56:14Z smit023 $

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"""
sparse this module provides basic pure python sparse matrix implementation
notably this allows the sparse matrix to be output in various formats
"""


class Matrix(dict):
    """This is a dictionary based sparse matrix class"""

    def __init__(self, rows, cols):
        """initialises the class by creating a matrix that will have the given
        rows and columns
        """
        self.rows = rows
        self.cols = cols
        self.rowdict = dict([(row, {}) for row in rows])
        self.coldict = dict([(col, {}) for col in cols])

    def add(self, row, col, item, colcheck=False, rowcheck=False):
        if not (rowcheck and row not in self.rows):
            if not (colcheck and col not in self.cols):
                dict.__setitem__(self, (row, col), item)
                self.rowdict[row][col] = item
                self.coldict[col][row] = item
            else:
                print(self.cols)
                raise RuntimeError("col %s is not in the matrix columns" % col)
        else:
            raise RuntimeError("row %s is not in the matrix rows" % row)

    def addcol(self, col, rowitems):
        """adds a column"""
        if col in self.cols:
            for row, item in rowitems.items():
                self.add(row, col, item, colcheck=False)
        else:
            raise RuntimeError("col is not in the matrix columns")

    def get(self, k, d=0):
        return dict.get(self, k, d)

    def col_based_arrays(self):
        numEls = len(self)
        elemBase = []
        startsBase = []
        indBase = []
        lenBase = []
        for i, col in enumerate(self.cols):
            startsBase.append(len(elemBase))
            elemBase.extend(list(self.coldict[col].values()))
            indBase.extend(list(self.coldict[col].keys()))
            lenBase.append(len(elemBase) - startsBase[-1])
        startsBase.append(len(elemBase))
        return numEls, startsBase, lenBase, indBase, elemBase


if __name__ == "__main__":
    """unit test"""
    rows = list(range(10))
    cols = list(range(50, 60))
    mat = Matrix(rows, cols)
    mat.add(1, 52, "item")
    mat.add(2, 54, "stuff")
    print(mat.col_based_arrays())
