new RST files for doc update

added new files for docs update

fixed cell for topfarm installation

new RST files for doc update

added new files for docs update

fixed cell for topfarm installation

fixed cost models and problems notebook

updated cost component API reference

new RST files for doc update

added new files for docs update

fixed cell for topfarm installation

new RST files for doc update

added new files for docs update

fixed cell for topfarm installation

fixed cost models and problems notebook

updated cost component API reference

updating cost component API reference

updating cost component API reference

fixed typo in cost model api reference

updating docs

fixed some typos

docs/source/installation.rst

 .. _installation:
 
-Installation
+Installation Guide
 ===========================
 
 
 Pre-Installation
 ----------------------------
+Before you can install the software, you must first have a working Python distribution with a package manager. For all platforms we recommend that you download and install Anaconda - a professional grade, full-blown scientific Python distribution.
 
-Before you can install the software, you must first have a working Python
-distribution with a package manager. For all platforms we recommend that you
-download and install Anaconda - a professional grade, full-blown scientific
-Python distribution.
-
-Install Anaconda, activate root environment:
+To set up Anaconda, you should:
 
     * Download and install Anaconda (Python 3.x version, 64 bit installer is recommended) from https://www.continuum.io/downloads
     
@@ -24,23 +20,23 @@ Install Anaconda, activate root environment:
         
         ``>> activate``
 
-If you have other Python programs besides TOPFARM, it is a good idea to install
-each program in its own environment to ensure that the dependencies for the
-different packages do not conflict with one another. The commands to create and
-then activate an environment in an Anaconda prompt are::
+It is recommended to create a new environment to install TOPFARM if you have other Python programs. This ensures that the dependencies for the different packages do not conflict with one another. In the command prompt, create and active an environment with::
 
-   conda create --name topfarm python=3.6
+   conda create --name topfarm python=3.8
    activate topfarm
 
 
 Simple Installation
 ----------------------------
 
+TOPFARM’s base code is open-sourced and freely available on `GitLab 
+<https://gitlab.windenergy.dtu.dk/TOPFARM/TopFarm2>`_ (MIT license).
+
 * Install from PyPi.org (official releases)::
   
     pip install topfarm
 
-* Install from GitLab  (includes any recent updates)::
+* Install from GitLab  (includes latest updates)::
   
     pip install git+https://gitlab.windenergy.dtu.dk/TOPFARM/TopFarm2.git
         
@@ -49,10 +45,7 @@ Simple Installation
 Developer Installation
 -------------------------------
 
-We highly recommend developers install TOPFARM into its own environment. (See
-instructions above.) The commands to clone and install TOPFARM with developer
-options into the current active environment in an Anaconda Prommpt are as
-follows::
+We highly recommend developers to install TOPFARM into the environment created previously. The commands to clone and install TOPFARM with developer options into the current active environment in an Anaconda Prompt are as follows::
 
    git clone https://gitlab.windenergy.dtu.dk/TOPFARM/TopFarm2.git
    cd TopFarm2

topfarm/cost_models/py_wake_wrapper.py

@@ -9,11 +9,10 @@ from topfarm.drivers.random_search_driver import RandomizeTurbinePosition_Circle
 from py_wake.deficit_models.gaussian import IEA37SimpleBastankhahGaussian
 import topfarm
 import numpy as np
-
+from scipy.interpolate import RegularGridInterpolator
 import warnings
 from py_wake.flow_map import Points
 from py_wake.utils.gradients import autograd
-from scipy.interpolate import RegularGridInterpolator
 
 
 class PyWakeAEP(AEPCalculator):