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 [PDF](https://powersasm.readthedocs.io/_/downloads/en/latest/pdf/)
 
+### What is PowerSAS.m?
+
 **PowerSAS.m** is a robust, efficient and scalable power grid analysis framework based on semi-analytical solutions (SAS) technology. The **PowerSAS.m** is the version for MATLAB/Octave users. It currently provides the following functionalities (more coming soon!):
 
 * **Steady-state analysis**, including power flow (PF), continuation power flow (CPF), contingency analysis.
@@ -16,3 +18,24 @@
 * **Enhanced computational performance.** Due to the analytical nature, PowerSAS provides model-adaptive high-accuracy approximation, which brings significantly extended effective range and much larger steps for steady-state/dynamic analysis. PowerSAS has been used to solve large-scale system cases with 200,000+ buses.
 * **Customizable and extensible.** PowerSAS supports flexible customization of grid analysis scenarios, including complex event sequences in extended simulation term.  
 
+### Installation
+#### 1. System requirements
+Matlab (7.1 or later) or GNU Octave (4.0.0 or later).
+
+#### 2. Installation
+ * Extract source code to a directory.
+ * Enter the directory in Matlab or GNU Octave.
+ * Execute command `setup`. You will see the following sub-directories:
+    * `/data`: Stores test system data, simulation settings data, etc.
+    * `/example`: Some examples of using PowerSAS.m.
+    * `/output`: Stores test result data.
+    * `/internal`: Internal functions of PowerSAS.m computation core.
+    * `/util`: Auxiliary functions including data I/O, plotting, data conversion, etc.
+    * `/logging`: Built-in logging system.
+    * `/doc`: Documentation.
+
+#### 3. Test
+ * Execute command `initpowersas` to initialize the environment, then execute `test_powersas` to run tests. You should expect all tests to pass.
+
+#### 4. Initialization
+To initialize PowerSAS.m, add the main directory of PowerSAS.m to your Matlab or GNU Octave path and run the command `initpowersas`. This will ensure that all the functions of PowerSAS.m are added to the path and thus callable.
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