added matrix power

Author: Phionx

README.md

@@ -30,9 +30,9 @@ pip install git+https://github.com/EQuS/jaxquantum.git
 
 If you are interested in contributing to the package, please clone this repository and install this package in editable mode after changing into the root directory of this repository:
 ```
-pip install -e ".[dev]"
+pip install -e ".[dev,docs]"
 ```
-This will also install extras from the `dev` flag, which can be useful when developing the package. Since this is installed in editable mode, the package will automatically be updated after pulling new changes in the repository. 
+This will also install extras from the `dev` and `docs` flags, which can be useful when developing the package. Since this is installed in editable mode, the package will automatically be updated after pulling new changes in the repository. 
 
 ### Installing from PyPI (not recommended)
 

docs/getting_started/installation.md

@@ -1,40 +1,30 @@
-# Installation
+## Installation
 
-*Conda users, please make sure to `conda install pip` before running any pip installation if you want to install `jaxquantum` into your conda environment.*
 
-`jaxquantum` is published on PyPI. So, to install the latest version from PyPI, simply run the following code to install the package:
+### Installing from source (recommended)
 
-```bash
-pip install jaxquantum
+**Recommended:** As this is a rapidly evolving project, we recommend installing the latest version of `jaxquantum` from source as follows:
+```
+pip install git+https://github.com/EQuS/jaxquantum.git
 ```
-If you also want to download the dependencies needed to run optional tutorials, please use `pip install jaxquantum[dev,docs]` or `pip install 'jaxquantum[dev,docs]'` (for `zsh` users).
-
-#### Building from source
 
-To build `jaxquantum` from source, pip install using:
+### Installing from source in editable mode (recommended for developers)
 
-```bash
-git clone git@github.com:EQuS/jaxquantum.git jaxquantum
-cd jaxquantum
-pip install --upgrade .
+If you are interested in contributing to the package, please clone this repository and install this package in editable mode after changing into the root directory of this repository:
 ```
+pip install -e ".[dev,docs]"
+```
+This will also install extras from the `dev` and `docs` flags, which can be useful when developing the package. Since this is installed in editable mode, the package will automatically be updated after pulling new changes in the repository. 
 
-If you also want to download the dependencies needed to run optional tutorials, please use `pip install --upgrade .[dev,docs]` or `pip install --upgrade '.[dev,docs]'` (for `zsh` users).
+### Installing from PyPI (not recommended)
 
-#### Installation for Devs
+`jaxquantum` is also published on PyPI. Simply run the following code to install the package:
 
-If you intend to contribute to this project, please install `jaxquantum` in editable mode as follows:
 ```bash
-git clone git@github.com:EQuS/jaxquantum.git jaxquantum
-cd jaxquantum
-pip install -e .[dev, docs]
+pip install jaxquantum
 ```
 
-Please use `pip install -e '.[dev, docs]'` if you are a `zsh` user.
-
-Installing the package in the usual non-editable mode would require a developer to upgrade their pip installation (i.e. run `pip install --upgrade .`) every time they update the package source code.
-
-#### Install with GPU support (Linux)
+### Install with GPU support (Linux)
 
 For linux users who wish to enable Nvidia GPU support, here are some steps ([ref](https://jax.readthedocs.io/en/latest/installation.html#nvidia-gpu)):
 

jaxquantum/core/qarray.py

@@ -200,6 +200,12 @@ def __mul__(self, other):
             self.data * multiplier,
             dims=self._qdims.dims,
         )
+
+    def __pow__(self, other):
+        if not isinstance(other, int):
+            return NotImplemented
+        
+        return powm(self, other)
 
     def __rmul__(self, other):
         return self.__mul__(other)
@@ -247,7 +253,6 @@ def space_dims(self):
         else:
             raise ValueError("Unsupported qtype.")
 
-    
     @property
     def data(self):
         return self._data
@@ -320,7 +325,7 @@ def keep_only_diag_elements(self):
 
 
 # Qarray operations ---------------------------------------------------------------------
-    
+
 def unit(qarr: Qarray) -> Qarray:
     """Normalize the quantum array.
 
@@ -390,6 +395,18 @@ def expm(qarr: Qarray, **kwargs) -> Qarray:
     data = expm_data(qarr.data, **kwargs)
     return Qarray.create(data, dims=dims)
 
+def powm(qarr: Qarray, n: int) -> Qarray:
+    """Matrix power.
+
+    Args:
+        qarr (Qarray): quantum array
+        n (int): power
+
+    Returns:
+        matrix power
+    """
+    data = jnp.linalg.matrix_power(qarr.data, n)
+    return Qarray.create(data, dims=qarr.dims)
 
 def cosm_data(data: Array, **kwargs) -> Array:
     """Matrix cosine wrapper.