am trying to plot P and Q but the matrix dimensions seems to disagree with me.

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vipul kumar 2020-4-22

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编辑： vipul kumar 2020-4-22

clc
clf
qmod = @(a) abs((k*exp(-2*(-(a + k)*(a - k))^(1/2))*(a/k - ((-(a + k)*(a - k))^(1/2)*1i)/k)*1i)/(exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2) + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2) + a*exp(-2*(-(a + k)*(a - k))^(1/2))*1i - a*exp(2*(-(a + k)*(a - k))^(1/2))*1i) + (k*exp(2*(-(a + k)*(a - k))^(1/2))*(a/k + ((-(a + k)*(a - k))^(1/2)*1i)/k))/(exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2)*1i + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2)*1i - a*exp(-2*(-(a + k)*(a - k))^(1/2)) + a*exp(2*(-(a + k)*(a - k))^(1/2))))^2/abs((k*exp(-2*(-(a + k)*(a - k))^(1/2))*1i)/(exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2) + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2) + a*exp(-2*(-(a + k)*(a - k))^(1/2))*1i - a*exp(2*(-(a + k)*(a - k))^(1/2))*1i) + (k*exp(2*(-(a + k)*(a - k))^(1/2)))/(a*exp(2*(-(a + k)*(a - k))^(1/2)) - a*exp(-2*(-(a + k)*(a - k))^(1/2)) + exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2)*1i + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - k))^(1/2)*1i))^2
normwave = @(a) 1/(1+(2.*a./31400))
a=linspace(0.1,1);
P=normwave(a);
Q=qmod(a);

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Rik 2020-4-22

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Answer 1

Rik 2020-4-22

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Somewhere in that humongous anonymous function you have made a mistake.

In this case the mistake is that you didn't use array operations, so all those products, powers and divisions are matrix operations.

Try to split qmod over multiple lines is segments that make sense. You could even consider writing the parts as separate anonymous functions. Then make sure to change matrix operations to array operations (replace * by .* etc).

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Rik 2020-4-22

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Your definition of normwave was also missing an array operator.

normwave = @(a) 1./(1+(2.*a./31400));
a=linspace(0.1,1);
P=normwave(a);
Q=qmod(a);
function val=qmod(a,k)
%apply values to anonymous function
if nargin==1
    k=1;%this value has to be set somehow
end
% %genarator code:
% syms r(z) s(z) a k
% ode1 = diff(r) == i*a*r+i*k*s;
% ode2 = diff(s) == -i*a*s-i*k*r;
% odes = [ode1 ; ode2];
% p = dsolve(odes);
% rSol(z) = p.r;
% sSol(z) = p.s;
% cond1 = r(-1) == 1;
% cond2 = s(1) == 0;
% conds = [cond1; cond2];
% [rSol(z), sSol(z)] = dsolve(odes,conds);
% q(a)=rSol(-1)./sSol(-1);
% clc,qmod=(abs(q)).^2
qmod_internal = @(a) abs((k*exp(-2*(-(a + k)*(a - k))^(1/2))*(a/k - ...
    ((-(a + k)*(a - k))^(1/2)*1i)/k)*1i)/(exp(-2*(-(a + k)*(a - ...
    k))^(1/2))*(-(a + k)*(a - k))^(1/2) + exp(2*(-(a + k)*(a - ...
    k))^(1/2))*(-(a + k)*(a - k))^(1/2) + a*exp(-2*(-(a + k)*(a - ...
    k))^(1/2))*1i - a*exp(2*(-(a + k)*(a - k))^(1/2))*1i) + ...
    (k*exp(2*(-(a + k)*(a - k))^(1/2))*(a/k + ((-(a + k)*(a - ...
    k))^(1/2)*1i)/k))/(exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - ...
    k))^(1/2)*1i + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - ...
    k))^(1/2)*1i - a*exp(-2*(-(a + k)*(a - k))^(1/2)) + a*exp(2*(-(a + ...
    k)*(a - k))^(1/2))))^2/abs((k*exp(-2*(-(a + k)*(a - ...
    k))^(1/2))*1i)/(exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - ...
    k))^(1/2) + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + k)*(a - ...
    k))^(1/2) + a*exp(-2*(-(a + k)*(a - k))^(1/2))*1i - a*exp(2*(-(a + ...
    k)*(a - k))^(1/2))*1i) + (k*exp(2*(-(a + k)*(a - ...
    k))^(1/2)))/(a*exp(2*(-(a + k)*(a - k))^(1/2)) - a*exp(-2*(-(a + ...
    k)*(a - k))^(1/2)) + exp(-2*(-(a + k)*(a - k))^(1/2))*(-(a + ...
    k)*(a - k))^(1/2)*1i + exp(2*(-(a + k)*(a - k))^(1/2))*(-(a + ...
    k)*(a - k))^(1/2)*1i))^2;
if isscalar(a)
    val=qmod_internal(a);
else
    val=arrayfun(qmod_internal,a);
end
end

Star Strider 2020-4-22

It defines the function handle for you. (Run those lines and then look at the results in your Command Window.) You only need to provide all the arguments.

Is there still a problelm in the functions produced by matlabFunction? (It specifies array operations, not matrix operations.) If so, it may be necessary to edit those functions to do matrix operations if those are what you want to do. That simply involves removing the dot operators from those operations, so multiplication becomes * rather than .*. You also need to be certain that the matrix sizes are conformable to the operations you want to do.

vipul kumar 2020-4-22

编辑：vipul kumar 2020-4-22

Yes that editing i did by replacing all '*' by '.*' and rik provided a much shorter method. But i could not obtain a plot P vs Q (ref is in the comments). P.S total noobie to programming.

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