Slycot fails to import when using control - python-3.x

Question

I cannot seem to get the control.ss2tf() function to work for state space MIMO system. The function works perfectly for a SISO system.
The following code is used to run the module:
control.ss2tf(A,B,C,D)
The resulting output indicated that the slycot module was not installed.
I then tried installing slycot with
pip install slycot
This command gave the following output:
Failed building wheel for slycot
Running setup.py clean for slycot
Failed to build slycot
Installing collected packages: slycot
Running setup.py install for slycot ... error
Complete output from command c:\users\wian\anaconda3\python.exe -u -c "import setuptools, tokenize;__file__='C:\\Users\\Wian\\AppData\\Local\\Temp\\pip-install-cmcxwtts\\slycot\\setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record C:\Users\Wian\AppData\Local\Temp\pip-record-_n6gj2yv\install-record.txt --single-version-externally-managed --compile:
Running from numpy source directory.
running install
running build
running config_cc
unifing config_cc, config, build_clib, build_ext, build commands --compiler options
running config_fc
unifing config_fc, config, build_clib, build_ext, build commands --fcompiler options
running build_src
build_src
building py_modules sources
building extension "slycot._wrapper" sources
f2py options: []
adding 'build\src.win-amd64-3.6\build\src.win-amd64-3.6\slycot\src\fortranobject.c' to sources.
adding 'build\src.win-amd64-3.6\build\src.win-amd64-3.6\slycot\src' to include_dirs.
adding 'build\src.win-amd64-3.6\slycot\src\_wrapper-f2pywrappers.f' to sources.
build_src: building npy-pkg config files
running build_py
copying slycot\version.py -> build\lib.win-amd64-3.6\slycot
copying build\src.win-amd64-3.6\slycot\__config__.py -> build\lib.win-amd64-3.6\slycot
running build_ext
Looking for python36.dll
Building import library (arch=AMD64): "c:\users\wian\anaconda3\libs\libpython36.a" (from c:\users\wian\anaconda3\python36.dll)
objdump.exe: c:\users\wian\anaconda3\python36.dll: file format not recognized
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\Wian\AppData\Local\Temp\pip-install-cmcxwtts\slycot\setup.py", line 241, in <module>
setup_package()
File "C:\Users\Wian\AppData\Local\Temp\pip-install-cmcxwtts\slycot\setup.py", line 233, in setup_package
setup(**metadata)
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\core.py", line 171, in setup
return old_setup(**new_attr)
File "c:\users\wian\anaconda3\lib\site-packages\setuptools\__init__.py", line 145, in setup
return distutils.core.setup(**attrs)
File "c:\users\wian\anaconda3\lib\distutils\core.py", line 148, in setup
dist.run_commands()
File "c:\users\wian\anaconda3\lib\distutils\dist.py", line 955, in run_commands
self.run_command(cmd)
File "c:\users\wian\anaconda3\lib\distutils\dist.py", line 974, in run_command
cmd_obj.run()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\command\install.py", line 62, in run
r = self.setuptools_run()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\command\install.py", line 36, in setuptools_run
return distutils_install.run(self)
File "c:\users\wian\anaconda3\lib\distutils\command\install.py", line 545, in run
self.run_command('build')
File "c:\users\wian\anaconda3\lib\distutils\cmd.py", line 313, in run_command
self.distribution.run_command(command)
File "c:\users\wian\anaconda3\lib\distutils\dist.py", line 974, in run_command
cmd_obj.run()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\command\build.py", line 47, in run
old_build.run(self)
File "c:\users\wian\anaconda3\lib\distutils\command\build.py", line 135, in run
self.run_command(cmd_name)
File "c:\users\wian\anaconda3\lib\distutils\cmd.py", line 313, in run_command
self.distribution.run_command(command)
File "c:\users\wian\anaconda3\lib\distutils\dist.py", line 974, in run_command
cmd_obj.run()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\command\build_ext.py", line 116, in run
force=self.force)
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\ccompiler.py", line 765, in new_compiler
compiler = klass(None, dry_run, force)
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\mingw32ccompiler.py", line 103, in __init__
build_import_library()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\mingw32ccompiler.py", line 415, in build_import_library
return _build_import_library_amd64()
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\mingw32ccompiler.py", line 471, in _build_import_library_amd64
generate_def(dll_file, def_file)
File "c:\users\wian\anaconda3\lib\site-packages\numpy\distutils\mingw32ccompiler.py", line 301, in generate_def
raise ValueError("Symbol table not found")
ValueError: Symbol table not found
I read that this is due to a FORTRAN compiler not installed on the system. I therefore installed gfortran with Ming32. To verify the install I ran the following:
(base) C:\WINDOWS\system32>gfortran
gfortran: fatal error: no input files
compilation terminated.
So gfortran is installed as a compiler, but yet pip remain unable to install slycot. I have also installed Microsoft Visual Studio 2017.
At this point I went to PyPi library to download the compiled binary of the slycot module. https://www.lfd.uci.edu/~gohlke/pythonlibs/
Here I downloaded the correct .whl file for my system (64 bit Python 3.6), and installed it with pip.
pip install "C:\Users\Wian\Desktop\slycot-0.3.3-cp36-cp36m-win_amd64.whl"
Using this command slycot 0.3.3 was installed successfully. However, when i run the command
control.ss2tf(A,B,C,D)
I get the following output
---------------------------------------------------------------------------
ImportError Traceback (most recent call last)
~\Anaconda3\lib\site-packages\control\xferfcn.py in _convertToTransferFunction(sys, **kw)
1089 try:
-> 1090 from slycot import tb04ad
1091 if len(kw):
ImportError: cannot import name 'tb04ad'
During handling of the above exception, another exception occurred:
TypeError Traceback (most recent call last)
<ipython-input-8-2b014ac15956> in <module>()
----> 1 control.ss2tf(Model)
~\Anaconda3\lib\site-packages\control\xferfcn.py in ss2tf(*args)
1315 sys = args[0]
1316 if isinstance(sys, StateSpace):
-> 1317 return _convertToTransferFunction(sys)
1318 else:
1319 raise TypeError("ss2tf(sys): sys must be a StateSpace object. It \
~\Anaconda3\lib\site-packages\control\xferfcn.py in _convertToTransferFunction(sys, **kw)
1113 # If slycot is not available, use signal.lti (SISO only)
1114 if (sys.inputs != 1 or sys.outputs != 1):
-> 1115 raise TypeError("No support for MIMO without slycot")
1116
1117 # Do the conversion using sp.signal.ss2tf
TypeError: No support for MIMO without slycot
When I try to import slycot in Python, I get the following result:
>>> import slycot
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Users\Wian\Anaconda3\lib\site-packages\slycot\__init__.py", line 18, in <module>
from .analysis import ab01nd,ab05md,ab05nd,ab07nd,ab08nd, \
File "C:\Users\Wian\Anaconda3\lib\site-packages\slycot\analysis.py", line 21, in <module>
from . import _wrapper
ImportError: DLL load failed: The specified module could not be found.
There is a _wrapper.pyd file in the Slycot directory (under Anaconda3\Libs\site-packages).
This is where I am currently stuck, and I cannot get Slycot to import correctly.
Your help is greatly appreciated!