下面显示的代码用于绘制Mandelbrot集,我认为我的代码有点冗余来构建Matrix M
.在Python中,我知道有一个干净的方法,
M = [[mandel(complex(r, i)) for r in np.arange(-2, 0.5,0.005) ] for i in np.range(-1,1,0.005)]
在Matlab中有类似的方法吗?
function M=mandelPerf() rr=-2:0.005:0.5; ii=-1:0.005:1; M = zeros(length(ii), length(rr)); id1 = 1; for i =ii id2 = 1; for r = rr M(id1, id2) = mandel(complex(r,i)); id2 = id2 + 1; end id1 = id1 + 1; end end function n = mandel(z) n = 0; c = z; for n=0:100 if abs(z)>2 break end z = z^2+c; end end
Luis Mendo.. 8
你可以完全避免循环.您可以z = z.^2 + c
以矢量化方式进行迭代.为了避免不必要的操作,在每次迭代时c
都要跟踪哪些点已超过您的阈值,并继续仅使用其余点进行迭代(这是索引的目的,ind
并ind2
在下面的代码中):
rr =-2:0.005:0.5; ii =-1:0.005:1; max_n = 100; threshold = 2; c = bsxfun(@plus, rr(:).', 1i*ii(:)); %'// generate complex grid M = max_n*ones(size(c)); %// preallocation. ind = 1:numel(c); %// keeps track of which points need to be iterated on z = zeros(size(c)); %// initialization for n = 0:max_n; z(ind) = z(ind).^2 + c(ind); ind2 = abs(z(ind)) > threshold; M(ind(ind2)) = n; %// store result for these points... ind = ind(~ind2); %// ...and remove them from further consideration end imagesc(rr,ii,M) axis equal