# Speedup Python with Cython, compared with Python C API and Julia and Dlang

Recently I read a wonderful series of posts about using Python C API to speedup python scripts. But I'm not a C fun and I used Cython to ease the work. So I wonder how much could I get using Cython instead of Python C API?

On the last post of the series, I found a Cython version implemented by Matthew Honnibal here. It is very fast but too *C++*. I hope I can write another but more *python* version.

At last, I got an cython implementation that operates on numpy ndarrays. The speed is comparable to Matthew's work, but looks more streight forward. I put the result below with no explaintion, but `Cython`

corresponds to Matthew's implementation and Cython PR is my *pythonic* implementation.

Also I tried the sample problem in both Julia and D lang. These languages are expected to achieve similar performance compared to C, but the implementations are maybe too naive to accomplish their top efficiency. These languages looks quite attractive and I spent hands of hours to read them but obviously not enough.

I plan to write a post about this when have time.

```
Cython PR (1): 8012 steps/sec
max(delta r): 0.0
max(delta v): 8.7e-18
max(delta F): 8.9e-16
Python (1): 125 steps/sec
max(delta r): 0.0
max(delta v): 0.0
max(delta F): 0.0
C Simple 1 (1): 6177 steps/sec
max(delta r): 0.0
max(delta v): 2.2e-16
max(delta F): 1.8e-15
C Simple 2 (1): 9158 steps/sec
max(delta r): 0.0
max(delta v): 0.0
max(delta F): 4.4e-16
C SIMD 1 (1): 9057 steps/sec
max(delta r): 0.0
max(delta v): 0.0
max(delta F): 6.7e-16
Cython (1): 8198 steps/sec
Cython PR (1): 8012 steps/sec
max(delta r): 0.0
max(delta v): 8.7e-18
max(delta F): 8.9e-16
Cython PR1d (1): 7448 steps/sec
max(delta r): 0.0
max(delta v): 4.4e-16
max(delta F): 8.9e-16
Cython PR1dV (1): 7546 steps/sec
max(delta r): 0.0
max(delta v): 2.8e-17
max(delta F): 1.8e-15
C OpenMP 1 (1): 8255 steps/sec
max(delta r): 0.0
max(delta v): 5.6e-17
max(delta F): 1.8e-15
C SIMD OpenMP 1 (1): 8283 steps/sec
max(delta r): 0.0
max(delta v): 1.4e-17
max(delta F): 8.9e-16
C OpenMP 1 (2): 12287 steps/sec
max(delta r): 0.0
max(delta v): 8.9e-16
max(delta F): 7.1e-15
C SIMD OpenMP 1 (2): 12209 steps/sec
max(delta r): 0.0
max(delta v): 2.2e-16
max(delta F): 1.8e-15
C OpenMP 1 (3): 7845 steps/sec
max(delta r): 2.2e-16
max(delta v): 2.2e-16
max(delta F): 4.4e-16
C SIMD OpenMP 1 (3): 6903 steps/sec
max(delta r): 0.0
max(delta v): 1.4e-17
max(delta F): 1.3e-15
C OpenMP 1 (4): 7085 steps/sec
max(delta r): 0.0
max(delta v): 2.2e-16
max(delta F): 1.4e-14
C SIMD OpenMP 1 (4): 6983 steps/sec
max(delta r): 0.0
max(delta v): 2.2e-16
max(delta F): 7.1e-15
```