I have a matlab function file called 'calculate_K_matrix.m ' which contains the following code:
function K = calculate_K_matrix(A, B, n)
K = place(A, B, eigs(A)*n)
end
I can call this from matlab like so:
addpath('/home/ash/Dropbox/SimulationNotebooks/Control')
A = [0 1 ;-100 -5]
B = [0 ; 7]
n = 1.1 % how aggressive feedback is
K = calculate_K_matrix(A, B, n)
but when I try to call this from python using the matlab engine API like so:
import matlab
import matlab.engine
eng = matlab.engine.start_matlab()
A = matlab.double([[0, 1],[-100, -5]])
B = matlab.double([[0],[7]])
n = 1.1 double(param initializer=None, param size=None, param is_complex=False)
n_matlab = matlab.double([n])
eng.addpath(r'/home/ash/Dropbox/SimulationNotebooks/Control')
K = eng.calculate_K_matrix(A, B, n_matlab)
Then I get the following error:
In [17]: run test.py
Attempt to execute SCRIPT calculate_K_matrix as a function:
/home/ash/Dropbox/SimulationNotebooks/Control/calculate_K_matrix.m
---------------------------------------------------------------------------
MatlabExecutionError Traceback (most recent call last)
/home/ash/Dropbox/SimulationNotebooks/Control/test.py in <module>()
10
11 eng.addpath(r'/home/ash/Dropbox/SimulationNotebooks/Control')
---> 12 K = eng.calculate_K_matrix(A, B, n_matlab)
/home/ash/anaconda2/envs/python3/lib/python3.5/site-packages/matlab/engine/matlabengine.py in __call__(self, *args, **kwargs)
76 else:
77 return FutureResult(self._engine(), future, nargs, _stdout,
---> 78 _stderr, feval=True).result()
79
80 def __validate_engine(self):
/home/ash/anaconda2/envs/python3/lib/python3.5/site-packages/matlab/engine/futureresult.py in result(self, timeout)
66 raise TypeError(pythonengine.getMessage('TimeoutCannotBeNegative'))
67
---> 68 return self.__future.result(timeout)
69
70 def cancel(self):
/home/ash/anaconda2/envs/python3/lib/python3.5/site-packages/matlab/engine/fevalfuture.py in result(self, timeout)
80 raise TimeoutError(pythonengine.getMessage('MatlabFunctionTimeout'))
81
---> 82 self._result = pythonengine.getFEvalResult(self._future,self._nargout, None, out=self._out, err=self._err)
83 self._retrieved = True
84 return self._result
MatlabExecutionError: Attempt to execute SCRIPT calculate_K_matrix as a function:
/home/ash/Dropbox/SimulationNotebooks/Control/calculate_K_matrix.m
How can I solve this issue?
Use getattr, like:
import matlab.engine
engine = matlab.engine.start_matlab()
engine.cd('<your path>')
getattr(engine, 'calculate_K_matrix')(A, B, n, nargout=0)
Thats how I do it:
import matlab.engine, sys, cmd, logging
class MatlabShell(cmd.Cmd):
prompt = '>>> '
file = None
def __init__(self, engine = None, completekey='tab', stdin=None, stdout=None):
if stdin is not None:
self.stdin = stdin
else:
self.stdin = sys.stdin
if stdout is not None:
self.stdout = stdout
else:
self.stdout = sys.stdout
self.cmdqueue = []
self.completekey = completekey
if engine == None:
try:
print('Matlab Shell v.1.0')
print('Starting matlab...')
self.engine = matlab.engine.start_matlab()
print('\n')
except:
logging.exception('>>> STARTUP FAILED')
input()
else:
self.engine = engine
self.cmdloop()
def do_run(self, line):
try:
getattr(self.engine, line)(nargout=0)
except matlab.engine.MatlabExecutionError:
pass
def default(self, line):
try:
getattr(self.engine, 'eval')(line, nargout=0)
except matlab.engine.MatlabExecutionError:
pass
if __name__ == "__main__":
MatlabShell()
