xrotor 0.0.16

Stripped down version of XROTOR as compiled python module

General
-------
This is a stripped down version of XROTOR. All the modification, design, and graphical functionality has
been removed. The only main menu options that are available in this stripped down version are:
* OPER, which allows for the calculation of performance characteristics at given operating conditions;
* BEND, which allows for the calculation of structural loads and deformations;
* NOIS, which allows for the calculation of the acoustic signature;
* LOAD, which loads a propeller definition file from the disk;
* SAVE, which saves a propeller definition file to the disk; and
* DISP, which displays the current propeller characteristics data onscreen.

Building and Installing the Python Module
-----------------------------------------
To successfully build and install the Python module a few prerequisites have to be present on your system. First of all,
a working installation of Python is required, of course. The module targets Python 3, and does NOT support Python 2.
Furthermore, working compilers for C and Fortran have to be installed and on the PATH. On Windows, the build and
installation have ONLY been tested with MinGW, using gcc and gfortran.

Then, installing XRotor should be as simple as running:

```bash
pip install xrotor
```

Or, from the root of the downloaded repository:

```bash
pip install .
```

On Windows, you may have to force the system to use MinGW. To do so, create a file named `distutils.cfg` in
`PYTHONPATH\Lib\distutils` with the following contents:

```INI
[build]
compiler=mingw32
```

If you are not able to create this file for your Python environment, it is also possible to force the use of MinGW
directly when invoking `pip` by calling:

```bash
pip install --global-option build_ext --global-option --compiler=mingw32 xrotor
```

Using the Module
----------------
All XRotor operations are performed using the `XRotor` class. So the first step when using this module is to create an
instance of this class:

```pycon
>>> from xrotor import XRotor
>>> xr = XRotor()
```

If this does not produce any errors, the installtion should be functioning properly.
A test case is installed along with the module. To run it in XRotor, execute the following commands in the same python
console:

```pycon
>>> from xrotor.model import Case
>>> from xrotor.test import case
>>> xr.case = Case.from_dict(case)
>>> xr.operate(1, 2000)

Iter dGmax @Imax gGrms Av Aw Be rlx
1 0.397E-01 1 0.167E-02 0.1553 0.1750 9.966 0.2000
2 0.225E-01 1 0.103E-02 0.1553 0.1764 9.966 0.2000
3 0.154E-01 1 0.733E-03 0.1553 0.1776 9.966 0.2000
4 0.116E-01 1 0.559E-03 0.1553 0.1824 9.966 1.0000
5 0.514E-03 29 0.224E-04 0.1553 0.1825 9.966 0.2000
6 0.412E-03 29 0.179E-04 0.1553 0.1825 9.966 1.0000
7 0.227E-05 29 0.742E-07 0.1553 0.1825 9.966 0.2000

```

These commands initialize a sample propeller definition in XRotor and operate it at a fixed RPM of 2000 rev/min. The
output from the last function should be familiar to anyone who has used the original XRotor console application before:
it is the convergence history of the OPER command. The familiar solution results can also be printed to the screen with
the following command:

```pycon
>>> xr.print_case()

===========================================================================
Free Tip Potential Formulation Solution:
Wake adv. ratio: 0.18252
no. blades : 2 radius(m) : 0.8300 adv. ratio: 0.15532
thrust(n) : 481. power(w) : 0.219E+05 torque(n-m): 105.
Efficiency : 0.5929 speed(m/s) : 27.000 rpm : 2000.000
Eff induced: 0.8510 Eff ideal : 0.8993 Tcoef : 0.4981
Tnacel(n) : 0.0132 hub rad.(m): 0.0600 disp. rad. : 0.0000
Tvisc(n) : -15.5982 Pvisc(w) : 0.615E+04
rho(kg/m3) : 1.22500 Vsound(m/s): 340.000 mu(kg/m-s) : 0.1789E-04
---------------------------------------------------------------------------
Sigma: NaN
Ct: 0.04658 Cp: 0.03833 j: 0.48795
Tc: 0.49815 Pc: 0.84023 adv: 0.15532

i r/r c/r beta(deg) cl Cd rEx10^6 Mach effi effp na.u/u
1 0.081 0.1458 59.81 0.433 0.0934 0.25 0.090 3.944 0.555 0.000
2 0.108 0.1475 56.04 0.501 0.0799 0.28 0.097 1.343 0.691 0.000
3 0.149 0.1500 50.09 0.602 0.0720 0.32 0.110 1.036 0.782 0.000
4 0.196 0.1527 43.42 0.642 0.0687 0.38 0.127 0.953 0.808 0.000
5 0.244 0.1558 36.98 0.624 0.0620 0.44 0.147 0.933 0.816 0.000
6 0.292 0.1594 31.45 0.581 0.0559 0.52 0.169 0.933 0.811 0.000
7 0.341 0.1634 27.32 0.544 0.0521 0.60 0.191 0.928 0.800 0.000
8 0.388 0.1672 24.38 0.521 0.0495 0.69 0.214 0.914 0.789 0.000
9 0.435 0.1697 22.20 0.506 0.0474 0.77 0.236 0.896 0.781 0.000
10 0.481 0.1699 20.38 0.494 0.0459 0.85 0.258 0.882 0.772 0.000
11 0.526 0.1679 18.76 0.484 0.0450 0.91 0.280 0.875 0.761 0.000
12 0.569 0.1639 17.37 0.476 0.0444 0.95 0.301 0.871 0.749 0.000
13 0.611 0.1583 16.20 0.471 0.0440 0.99 0.322 0.867 0.738 0.000
14 0.652 0.1515 15.24 0.470 0.0438 1.00 0.342 0.864 0.729 0.000
15 0.690 0.1438 14.45 0.471 0.0436 1.00 0.361 0.860 0.722 0.000
16 0.727 0.1356 13.78 0.475 0.0436 0.99 0.380 0.856 0.715 0.000
17 0.762 0.1271 13.22 0.479 0.0438 0.98 0.397 0.853 0.709 0.000
18 0.794 0.1188 12.73 0.483 0.0441 0.95 0.414 0.849 0.702 0.000
19 0.825 0.1106 12.29 0.486 0.0447 0.92 0.429 0.846 0.694 0.000
20 0.853 0.1029 11.91 0.487 0.0455 0.88 0.443 0.843 0.685 0.000
21 0.879 0.0958 11.57 0.485 0.0466 0.84 0.456 0.838 0.673 0.000
22 0.903 0.0892 11.26 0.479 0.0481 0.81 0.468 0.832 0.660 0.000
23 0.924 0.0834 10.99 0.468 0.0501 0.77 0.479 0.824 0.642 0.000
24 0.943 0.0782 10.74 0.450 0.0529 0.74 0.488 0.813 0.618 0.000
25 0.959 0.0738 10.53 0.423 0.0570 0.71 0.496 0.796 0.585 0.000
26 0.972 0.0701 10.35 0.385 0.0635 0.68 0.503 0.775 0.537 0.000
27 0.983 0.0672 10.20 0.335 0.0740 0.66 0.509 0.747 0.467 0.000
28 0.991 0.0651 10.08 0.270 0.0913 0.65 0.513 0.713 0.365 0.000
29 0.997 0.0636 10.01 0.193 0.1177 0.63 0.516 0.675 0.236 0.000
30 0.999 0.0629 9.97 0.125 0.1467 0.63 0.518 0.642 0.123 0.000
```

If the module is working as it should, the output should match the output shown above.

At the time of writing, the only the two operating modes available are fixed RPM and fixed thrust with fixed blade pitch.
Both can be invoked by calling the `operate` member function on an instance of the `XRotor` class. The first argument
to this function specifies which mode is used: 1 for fixed RPM, as was demonstrated above; 2 for fixed thrust at fixed
blade pitch. The second argument to the function specifies the value for the RPM/thrust.

See the documentation for more detailed explanation of how to use the API.