## Aim¶

Minimize $$\sum_i \mathrm{distance}^2(\vec r_i, \mathrm{line})=\sum_i (\vec r_i\cdot \hat n-\rho)^2$$ for line $\vec r\cdot \hat n-\rho=0$. It is equivalent …

## Convert str(array) back to numpy array

If we print a numpy array, which actually use str(), we will find it almost irreversible.

In [5]:
l=arange(16).reshape(4,4)
print('l is printed as:\n …

## 数据分析¶

In [2]:
import pandas as pd
from functools import …

## Reduced density matrix and partial trace

The reduced matrix is defined as the partial trace of the density matrix. In linear algebra and functional analysis, the partial trace is a generalization of the trace. Whereas the trace is a scalar valued function on operators, the partial trace is an operator-valued function. The partial trace has applications in quantum information and decoherence which is relevant for quantum measurement and thereby to the decoherent approaches to interpretations of quantum mechanics, including consistent histories and the relative state interpretation.

## ipynb2pelican Plugin released!

Yet another Pelican Plugin for blogging with Jupyter Notebooks using MetaCell to store metadata.

Thanks to super cow power of python, we can finally publish ipynb easily! Below is the …

## Next Permutation

Aim: Find a larger permutation

We must move a larger number forward. So we should go from the tail to find any new number is smaller than a number behind …