Vector must be the same length.

I created the m.file to plot alpha vs Vnorm but the vector is not the same length ,its request to hellp me at this stage

D=15;

tmpI=eye(D);

ket0=tmpI(:,1); %|0>
ket1=tmpI(:,2); %|1>
ket2=tmpI(:,3); %|2>
ket3=tmpI(:,4); %|3>
ket4=tmpI(:,5); %|4>
ket5=tmpI(:,6); %|5>
ket6=tmpI(:,7); %|6>
ket7=tmpI(:,8); %|7>
ket8=tmpI(:,9); %|8>
ket9=tmpI(:,10); %|9>
ket10=tmpI(:,11); %|10>
ket11=tmpI(:,12); %|11>
ket12=tmpI(:,13); %|12>
ket13=tmpI(:,14); %|13>
ket14=tmpI(:,15); %|14>
sym n
alpha1 =0.03;
ketalpha1 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
sym n
alpha2 =0.06;
ketalpha2 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
sym n
alpha3 =0.09;
ketalpha3 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
sym n
alpha4 =0.12;
ketalpha4 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
sym n
alpha5 =0.15;
ketalpha5 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
sym n
alpha6 =0.18;
ketalpha6 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*(ket1+ket2+ket3+ket4+ket5+ket6+ket7+ket8+ket9+ket10+ket11+ket12+ket13+ket14);
creation=circshift(diag(sqrt(0:1:14)),-1);
annihilation=creation';
V1=annihilation*ketalpha1-alpha1*ketalpha1;
V2=annihilation*ketalpha2-alpha2*ketalpha2;
V3=annihilation*ketalpha3-alpha3*ketalpha3;
V4=annihilation*ketalpha4-alpha4*ketalpha4;
V5=annihilation*ketalpha5-alpha5*ketalpha5;
V6=annihilation*ketalpha6-alpha6*ketalpha6;
Vnorm1=V1*V1';
Vnorm2=V2*V2';
Vnorm3=V3*V3';
Vnorm4=V4*V4';
Vnorm5=V5*V5';
Vnorm6=V6*V6';
plot(Vnorm1,alpha1,Vnorm2,alpha2,Vnorm3,alpha3,Vnorm4,alpha4,Vnorm5,alpha5,Vnorm6,alpha6);

Answer 1

[Dyuman Joshi]

I have tidied up your code. Avoid using dynamically named variables as much as you can, it is not recommended, Indexing is much simpler and efficient.

Read - Why Variables should not be named Dynamically

Coming onto the issue, alpha1 is a scalar and Vnorm1 is a matrix. How exactly do you plan to plot a scalar against a matrix (or vice-versa) ?

D = 15;
tmpI = eye(D);
%sum of ket1 to ket14 is
ket = [0;ones(14,1)];

syms n
ct = 6;

creation = circshift(diag(sqrt(0:1:14)),-1);
annihilation = creation';
%pre-allocation
[ketalpha, V, Vnorm] = deal(cell(1,ct));

for k=1:ct
    alpha = 0.03*k;
    temp0 = symsum(exp(-abs(alpha)^2 * alpha^n / sqrt(factorial(n)) ), n, 0, 14)*ket;
    ketalpha{k} = temp0;
    temp1 = annihilation*temp0 - alpha*temp0;
    V{k} = temp1;
    Vnorm{k} = temp1*temp1';
end

[Abu Zar]

Hello sir,your code is very helpful. Please, how to put the another's values 0.06,0.09,0.12,0.15,0.18 for alpha? I want to find the plot of alpha, Vnorm.

I think the plot will if I find the numeric value. How I can find the numeric value of for plot? For example of the plot given below

xlist=1:1:10

xlist = 1×10

1 2 3 4 5 6 7 8 9 10

for id=1:10
    ylist(id)=xlist(id)*2;
end
plot(xlist, ylist, 'b.-', 'MarkerSize', 20)
grid on

[Dyuman Joshi]

"Please, how to put the another's values 0.06,0.09,0.12,0.15,0.18 for alpha?"

I have already taken care of that in the code, as you can see below

ct=6;
for k=1:ct
    alpha = 0.03*k

So, here

ketalpha{1} is ketalpha1, ketalpha{2} is ketalpha2 and so on,

Similarly, V{1} is V1, V{2} is V2, ... Vnorm{1} is Vnorm1, Vnorm{2} is Vnorm2 ...

"I want to find the plot of alpha, Vnorm."

As I mentioned earlier, alpha is a scalar and Vnorm is a matrix.

How exactly do you plan to plot a scalar against a matrix? The example you have shown is plotting vector vs vector.

What exactly are you trying to do?

[Abu Zar]

Thank you very much.

basically i want to do this two question

[Dyuman Joshi]

With the result you want to get, I think you have the multiplication order incorrect -

D = 15;
tmpI = eye(D);
%sum of ket1 to ket14 is
%generalised this line of code for any value of D
ket = sum(tmpI(:,2:D),2);
syms n
ct = 6;

creation = circshift(diag(sqrt(0:1:(D-1))),-1);
annihilation = creation';
%pre-allocation
%[ketalpha, V, Vnorm] = deal(cell(1,ct));
Vnorm = zeros(1,ct);
alpha = 0.03*(1:ct);

%loop for calculation
for k = 1:ct
    temp0 = symsum(exp(-abs(alpha(k))^2 * alpha(k)^n / sqrt(factorial(n)) ), n, 0, 14)*ket;
    %ketalpha{k} = temp0;
    temp1 = annihilation*temp0 - alpha(k)*temp0;
    %V{k} = temp1;
    Vnorm(k) = temp1'*temp1;
end
plot(alpha,Vnorm, '-*k')
xlim([0 0.21])
xticks(0:0.03:0.21)
xlabel('alpha', 'Color', 'b', 'FontSize', 15)
ylabel('Vnorm', 'Color', 'b', 'FontSize', 15)

[Abu Zar]

it's outstanding.

thank you very much.

[Dyuman Joshi]

You are welcome!

[Abu Zar]

Hi,

the temp1>>1,i want to evaulate the temp1<<1,

I try to use vpa(temp) then double(vpa(temp) but i did not get my result.

can i get my result if i use any other technique in this m.file.

thanks.

[Dyuman Joshi]

I dont understand what you are trying to convey.

[Abu Zar]

let me explain little again

i want Temp1’*temp1 should be << 1 but my value Temp1’*temp1 >>1 ,also plot show this,

Can you check it?

somone recommend me to use a column vector to define temp0. For example.

temp0=zeros(D,1);

for id =0:D-1

Temp0(id)=...

end

Then, you can give a numeric result.

i try my self but not know how to do this above recommandtion.

[Dyuman Joshi]

"my value Temp1’*temp1 >>1"

Yes the values are big, in the order of 10^4, do you mean to say this?

"i want Temp1’*temp1 should be << 1"

For that you will have to change the data. For the given data, you can't modify the outcome.

"Then, you can give a numeric result."

Which result?

[Abu Zar]

Hello Sir,

please help me to put follow this message in these codes ;

---->Temp0 is a sum from n=0 to n=14. try the following and find the result, please.

for n=0:14

temp0 =temp0+ double(symsum(exp(-0.5*abs(alpha(k))^2)* alpha(k)^n / sqrt(factorial(n)), n, 0, 14)*ket);

end

Thank you

[Dyuman Joshi]

Message? as in a comment?

Or do you want to include this in the code?

[Abu Zar]

Yes I want to include 🙏 Thank you

[Dyuman Joshi]

D = 15;
tmpI = eye(D);
%sum of ket1 to ket14 is
%generalised this line of code for any value of D
ket = sum(tmpI(:,2:D),2);
syms n
ct = 6;

creation = circshift(diag(sqrt(0:1:(D-1))),-1);
annihilation = creation';
%pre-allocation
Vnorm = zeros(1,ct);
alpha = 0.03*(1:ct);

temp0=0;

%loop for calculation
for k = 1:ct
    temp0 = temp0 + symsum(exp(-abs(alpha(k))^2*alpha(k)^n/sqrt(factorial(n))), n, 0, 14)*ket;
    temp1 = annihilation*temp0 - alpha(k)*temp0;
    Vnorm(k) = temp1'*temp1;
end
plot(alpha,Vnorm, '-*k')
xlim([0 0.21])
xticks(0:0.03:0.21)
xlabel('alpha', 'Color', 'b', 'FontSize', 15)
ylabel('Vnorm', 'Color', 'b', 'FontSize', 15)

[Abu Zar]

Sir,in this way i improved my plot this becoming less then 1 but last value is very large ,please help me to solve this point,you can see my plot.

[Abu Zar]

D = 15;
tmpI = eye(D);
%sum of ket1 to ket14 is
%generalised this line of code for any value of D
ket = sum(tmpI(:,1:D),1)';
syms n
ct = 6;

creation = circshift(diag(sqrt(0:1:(D-1))),-1);
annihilation =creation';
%pre-allocation
%[ketalpha, V, Vnorm] = deal(cell(1,ct));
Vnorm = zeros(1,ct);
alpha = 0.03*(1:ct);
temp0=0;
%loop for calculation
for k = 1:ct
    temp0 =14*temp0+double(symsum(exp(0.5*(-abs(alpha(k))^2))* alpha(k)^n / sqrt(factorial(n)), n, 0, 14)*ket);
    %ketalpha{k} = temp0;
    %temp2= annihilation*temp0;
    temp1 = annihilation*temp0 - alpha(k)*temp0;
    %V{k} = temp1;
    Vnorm(k) = temp1'*temp1;
    
end
plot(alpha,Vnorm, '-*k')
xlim([0 0.21])
%xticks(0:0.03:0.21)
xlabel('alpha', 'Color', 'b', 'FontSize', 15)
ylabel('Vnorm', 'Color', 'b', 'FontSize', 15)

[Dyuman Joshi]

You changed the definition of the variable 'ket', I don't know why.

At this point, I do not know what you are trying to achieve.

If you are doing a Homework question, copy and paste the original question. Otherwise, I don't understand what you are trying to convey.

[Abu Zar]

hello sir you know my codes ,i check values of every variables but i did not got the values of n, i put the values of n from 0 to 14.

[Dyuman Joshi]

"but i did not got the values of n"

Because you have not assigned any value to n.

"i put the values of n from 0 to 14."

Yes, to find the value of a sum, with respect to a variable. But the value of n has not been explicitly defined.