2011/8/2 Yu Zhang <[email protected]>: > Dear Shavkat, > > Here is partial code from known_results.py. > > class sigma(Callback): > def __init__(self, sig): > Callback.__init__(self) > self.sig=sig > > def double_vec(self,r): > return self.sig > > s= structure(v, eps) > pol1 = sigma(7.63) > set_DBL1_Callback(pol1.__disown__()) > s.add_polarizability(DBL1, 0.3, 0.1) > > At your convenience, can you explain the following to me, > > 1) what is the variable DBL1 ? Does it store the sigmas for all cells ?
There are some requirements for callback functions (callback is python code which is called by C/C++ library). Details are complex and boring, you may look at SWIG documentation on particular details. In general, you can not callback python code directly within C++ library that expects pointer to a function to be passed. To overcome this a bunch of proxy functions are declared within SWIG and they are generally given names like EPS, MU, COND, SIGMA and as a spare DBL*, CMPL*. After that it became possible to pass a pointer to these functions as a callback functions, and these proxies are implemented so that they call python code. That is why it is strictly required to pass those proxies as a function pointer. pol1 = sigma(7.63) set_DBL1_Callback(pol1.__disown__()) This part creates a python class (sigma) and sets it as a callback to the DBL1 proxy. Now calls to DBL1 will result in call to the pol1.double_vec(). If callback is not set function will return 0, otherwise it will return some value. s.add_polarizability(DBL1, 0.3, 0.1) Now this DBL1 proxy function is passed to add_polarizability. And, as you have added it to the structure it will be called for the whole cell - it means at any grid point in the simulation cell, point vector is passed as a vector. You may want to look inside meep_common.i and custom.hpp for the details on implementation. > 2) what are the third and the second parameter in function > add_polarizability() (last line)? s.add_polarizability(DBL1, 0.3, 0.1) according to python-meep sources this call is overloaded and in this case meanings are: DBL1 - a pointer to function 0.3 - omega 0.1 - gamma. there is another sample in the python-meep sources - dispersive.py Strange, but looking into the latest meep sources I can not find add_polarizability anymore. Probably it is time for me to check how python-meep works with latest meep. They said that they will release a new version soon and it will be sad if python-meep will not be compatible. Can you please confirm that known_results works OK in your case and what version of meep you are using? Kind regards, Shavkat Nizamov _______________________________________________ Mailing list: https://launchpad.net/~python-meep Post to : [email protected] Unsubscribe : https://launchpad.net/~python-meep More help : https://help.launchpad.net/ListHelp
