Robert, Transforming your matrix to a list before computation isn't very efficient. If you do need some extra parameters in your __init__ to be compatible with other functions such as asmatrix, well, just add them, or use a coverall **kwargs def __init__(self, instruments, **kwargs) No guarantee it'll work all the time.
Otherwise, please have a look at: http://docs.scipy.org/doc/numpy/user/basics.subclassing.html and the other link at the top of that page. In your case, I'd try to put the initialization in the __array_finalize__. On Dec 10, 2008, at 7:15 AM, <[EMAIL PROTECTED]> <[EMAIL PROTECTED] > wrote: > Hello, > > I'm using numpy-1.1.1 for Python 2.3. I'm trying to create a class > that acts just like the numpy.matrix class with my own added methods > and attributes. I want to pass my class a list of custom > "instrument" objects and do some math based on these objects to set > the matrix. To this end I've done the following: > > from numpy import matrix > > class rcMatrix(matrix): > def __init__(self,instruments): > """Do some calculations and set the values of the matrix.""" > self[0,0] = 100 # Just an example > self[0,1] = 100 # The real init method > self[1,0] = 200 # Does some math based on the input objects > self[1,1] = 300 # > def __new__(cls,instruments): > """When creating a new instance begin by creating an NxN > matrix of > zeroes.""" > len_ = len(instruments) > return matrix.__new__(cls,[[0.0]*len_]*len_) > > It works great and I can, for example, multiply two of my custom > matrices seamlessly. I can also get the transpose. However, when I > try to get the inverse I get an error: > >> rcm = rcMatrix(['instrument1','instrument2']) >> print rcm > [[ 100. 100.] > [ 200. 300.]] >> print rcm.T > [[ 100. 200.] > [ 100. 300.]] >> print [5,10] * rcm > [[ 2500. 3500.]] >> print rcm.I > Traceback (most recent call last): > File "[Standard]/deleteme", line 29, in ? > File "C:\Python23\Lib\site-packages\numpy\core\defmatrix.py", line > 492, in getI > return asmatrix(func(self)) > File "C:\Python23\Lib\site-packages\numpy\core\defmatrix.py", line > 52, in asmatrix > return matrix(data, dtype=dtype, copy=False) > TypeError: __init__() got an unexpected keyword argument 'dtype' > > > > I've had to overwrite the getI function in order for things to work > out: > > def getI(self): return matrix(self.tolist()).I > I = property(getI, None, doc="inverse") > > Is this the correct way to achieve my goals? > > Please let me know if anything is unclear. > > Thanks, > > Robert Conde > > > _______________________________________________ > Numpy-discussion mailing list > Numpy-discussion@scipy.org > http://projects.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
