Question

如何以元素方式将scipy.sparse矩阵提升为幂？根据{{3}}，numpy.power应该这样做，但它在稀疏矩阵上失败了：

>>> X
<1353x32100 sparse matrix of type '<type 'numpy.float64'>'
        with 144875 stored elements in Compressed Sparse Row format>

>>> np.power(X, 2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../scipy/sparse/base.py", line 347, in __pow__
    raise TypeError('matrix is not square')
TypeError: matrix is not square

与X**2相同的问题。转换为密集阵列有效，但浪费了宝贵的时间。

我遇到np.multiply同样的问题，我使用稀疏矩阵的multiply方法解决了这个问题，但似乎没有pow方法。

Answer 1

这有点低级，但对于元素操作，您可以直接使用基础数据数组：

>>> import scipy.sparse
>>> X = scipy.sparse.rand(1000,1000, density=0.003)
>>> X = scipy.sparse.csr_matrix(X)
>>> Y = X.copy()
>>> Y.data **= 3
>>> 
>>> abs((X.toarray()**3-Y.toarray())).max()
0.0

Answer 2

我刚遇到同样的问题，发现稀疏矩阵现在支持元素功率。对于上述情况，它应该是：

private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new 
ViewPagerAdapter(getSupportFragmentManager());

 //change the fragmentName as per your need

    adapter.addFragment(new FirstFragment(), "OVERVIEW");
    adapter.addFragment(new Secondfragment(), "TRAILER");
    adapter.addFragment(new thirdFragment(), "ORDERS");
    viewPager.setAdapter(adapter);
}

class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragmentList.get(position);
    }

    @Override
    public int getCount() {
        return mFragmentList.size();
    }

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }


}

scipy.sparse矩阵的元素功效

2 个答案: