Problem saving vectors in a for loop

Question

Travis 2014-4-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/127057-problem-saving-vectors-in-a-for-loop

评论： Travis 2014-4-25

Hi all,

I am having trouble saving the vectors that I generate using a for loop. Running the code, that I have provided below, updates the 3D plot for each iteration. I would like to save each vector for each iteration and plot them all together. I believe the problem lies with the counter "xx" but I am unsure how to get around this since I want to save the vector "C" for each iteration which does not use "xx" as a counting variable. I have tried indexing "C" with "xx" to save the vector for each iteration Any help would be greatly appreciated.

for xx=0:5:350;
d2(1:71)=xx;
lambda=400:5:750;
d1=0.34;
% Define Refractive Indices for Materials:
% Air:
n_0=1;
% Graphene present & not present:
n_1=2.6-1.3i;
n_11=1;
% SiO2 (400-750nm):
n_2=[1.4701 1.4696 1.4691 1.4686 1.4681 1.4676 1.4672 1.4668 1.4663...
    1.466 1.4656 1.4652 1.4648 1.4645 1.4641 1.4638 1.4635 1.4632 1.4629...
    1.4626 1.4623 1.4621 1.4618 1.4615 1.4613 1.461 1.4608 1.4606 1.4603 1.4601...
    1.4599 1.4597 1.4595 1.4593 1.4591 1.4589 1.4587 1.4586 1.4584 1.4582 1.458 1.4579...
    1.4577 1.4576 1.4574 1.4572 1.4571 1.457 1.4568 1.4567 1.4565 1.4564 1.4563 1.4561 1.456...
    1.4559 1.4558 1.4556 1.4555 1.4554 1.4553 1.4552 1.4551 1.455 1.4549 1.45475 1.4546 1.4545 1.4544 1.4543 1.4542];
% Silicon (400-750nm):
n_3=[5.554925088 5.422277418 5.302243523 5.193611448 5.095262656 5.006167192 4.925378971...
    4.852031185 4.785331843 4.724559421 4.669058654 4.618236434 4.57155784 4.528542299 4.488759852...
    4.451827565 4.417406046 4.3851961 4.354935495 4.326395864 4.299379722 4.273717609 4.249265359 4.225901491...
    4.203524726 4.182051619 4.161414333 4.141558515 4.12244131 4.1040295 4.086297753 4.069227011 4.052802995 4.03701484...
    4.021853804 4.00731224 3.9933825 3.980056106 3.967322993 3.955170878 3.943584754 3.932546514 3.922034693 3.912024332 3.902486974...
    3.893390776 3.884700748 3.876379115 3.868385805 3.860679058 3.853216158 3.845954294 3.838851539 3.831867956 3.824966827 3.818116006 3.811289394...
    3.804468544 3.797644378 3.790819041 3.784007871 3.777241493 3.770568042 3.7640555 3.75779417 3.751899264 3.746513614 3.741810515 3.737996688 3.735315359 3.734049478];
% Define r constants:
% For graphene on Si02:
r1=(n_0-n_1)./(n_0+n_1);
r2=(n_1-n_2)./(n_2+n_1);
r3=(n_2-n_3)./(n_2+n_3);
% Plain Si02 no graphene:
r11=(n_0-n_11)./(n_0+n_11);
r21=(n_11-n_2)./(n_2+n_11);
r31=(n_2-n_3)./(n_2+n_3);
% Define phase shifts:
psi1=(2*pi*n_1*d1)./lambda;
psi2=(2*pi*n_2.*d2)./lambda;
psi11=(2*pi*n_11*d1)./lambda;
psi21=(2*pi*n_2.*d2)./lambda;
% Intensity equation with graphene (I1) and without (I2):
I1=abs((r1.*exp(1i.*(psi1+psi2))+r2.*exp(-1i.*(psi1-psi2))+r3.*exp(-1i.*(psi1+psi2))...
    +r1.*r2.*r3.*exp(1i.*(psi1-psi2))).*(exp(1i.*(psi1+psi2))+r1.*r2.*exp(-1i.*(psi1-psi2))+r1.*r3.*exp(-1i.*(psi1+psi2))+r2.*r3.*exp(1i.*(psi1-psi2))).^-1).^2;
I2=abs((r11.*exp(1i.*(psi11+psi21))+r21.*exp(-1i.*(psi11-psi21))+r31.*exp(-1i.*(psi11+psi21))...
    +r11.*r21.*r31.*exp(1i.*(psi11-psi21))).*(exp(1i.*(psi11+psi21))+r11.*r21.*exp(-1i.*(psi11-psi21))...
    +r11.*r31.*exp(-1i.*(psi11+psi21))+r21.*r31.*exp(1i.*(psi11-psi21))).^-1).^2;
% Contrast equation:
C=(I2-I1)./I2;
figure(1);plot3(lambda,d2,C);
figure(2);plot(lambda,C);
figure(3);plot(d2,C);
end

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

dpb 2014-4-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/127057-problem-saving-vectors-in-a-for-loop#answer_134455

在 MATLAB Online 中打开

One way to rearrange the loop...

Instead of

for xx=0:5:350;
  d2(1:71)=xx;
  ...

write

xx=0:5:350;
for ix=1:length(xx)
  d2(1:71)=xx(ix);
  ....

Then you've got an index variable that increments by one each pass. You will, of course, need to change any other references to xx to refer to the array instead of the index variable before; I didn't try to read the rest of the code. d2(1:71)=xx;