kinor
Posts:
181
Registered:
11/19/09


Re: speeding up assigning values to a matrix
Posted:
Apr 5, 2013 12:06 PM


"Luca " <l.presottoRE@MOVE.campus.unimib.NOTit> wrote in message <kjmqpp$4r7$1@newscl01ah.mathworks.com>... > "kinor" wrote in message <kjmptu$20a$1@newscl01ah.mathworks.com>... > > > Hi Luca, > > i guess your mask(:,:,:,3) = (mask>4 &mask<7)*255; > > should be maskC(:,:,:,3) = (mask>4 &mask<7)*255; ? > > Yes, of course! > > > I'm going to try how faster your version is. > I would not expect reducing the number of scalar multiplications to provide great improvements. > You don't see either a way to use logical indexing, do you?
there is a way which is slower than
ts=tic; maskC(:,:,:,1) = (mask==uint8(2)); % toc(ts); % ts=tic; maskC(:,:,:,2) = (mask==uint8(4)); % toc(ts); % ts=tic; maskC(:,:,:,3) = (mask==uint8(6)); % toc(ts); % tic maskC = maskC*255; toc(ts)
still wonder how much time is needed on your system...

