On Thu, Feb 25, 2010 at 12:52 AM, Gökhan Sever <gokhanse...@gmail.com> wrote: > Hello, > > I am working on a code shown at > http://code.google.com/p/ccnworks/source/browse/trunk/thesis/part1/logn-fit.py > > I use the code to analyse a couple dataset also placed in the same > directory. In the first part I use for-loops all over, but later decided to > write them without using for loops. The script runs correctly for the two > section, however I have a few question regarding to the for-less structures: > > This part is taken after line 371: > > gm10 = np.exp((1/Nt10)*(h10*np.log(Dp)).sum(axis=1)) > gsd10 = > np.exp(((1/Nt10)*(h10*np.log(Dp/gm10[:,np.newaxis])**2).sum(axis=-1))**0.5) > > dN_dDp10 = > (Nt10[:,np.newaxis]/((2*np.pi)**0.5*np.log(gsd10[:,np.newaxis])*d))*np.exp(-(np.log(d)-\ > > np.log(gm10[:,np.newaxis]))**2/(2*np.log(gsd10[:,np.newaxis])**2)) > > a10 = (dN_dDp10[0:300,d >= dc10u]*0.001).sum(axis=1) > > Shape informations for the arrays as follow: > > I[306]: gm10.shape; gsd10.shape, Dp.shape, d.shape, dN_dDp10.shape, > a10.shape > O[306]: (300,), (300,), (11,), (991,), (300, 991), (300,) > > 1-) In gsd10 line what does axis=-1 really means, and why negative axis > value is allowed? >
-1 in this case is the last axis I believe. gsd10.shape[-1] Or just like in python [1,2,3,4][-1] 4 > 2-) [:,np.newaxis] decreases the readability of the code. Is there any > alternative for it? > I find [:,None] to be the easiest unless I want to be really explicit about a reshape. It's probably just as bad though. np.ones(8).shape (8,) np.expand_dims(np.ones(8),1).shape (8, 1) np.ones(8).reshape(8,-1).shape (8, 1) > 3-) In the last line (dN_dDp10[0:300,d >= dc10u]) could I achieve the same > result with different syntax? I have found it somewhat not in accordance > with the previous lines. > If it's an array you could just define it once as index_d or something beforehand to increase readability? Skipper > Thanks for your time and comments. > > -- > Gökhan > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion