Plot generating blank graph?

I have a code that stores values, calculates new values, then runs those calcuated variables through a for loop with two separate equations (Im1 and Im6), each with an unknown variable "t". However, when I ask MATLAB to plot the results of the loops, all I receive is a blank graph, as seen in the attachment. It is supposed to appear similar to the graph in the second attachment, with two lines for each of the equations. I don't know what is going wrong. I've added my current script below. Thank you.

l = 0.0001;
lambda = 0.405;
syms t;

wj11 = 0;
wj12 = -79.077;
wj61 = 0;
wj62 = -0.014533;
wj63 = -0.0682;
wj64 = -0.1947;
wj65 = -1.023;
wj66 = -2.896;
wj67 = -79.4;

Bj11 = 0.00097;
Bj12 = 0.99903;
Bj61 = Bj11;
Bj62 = 0.000091;
Bj63 = 0.000664;
Bj64 = 0.000901;
Bj65 = 0.001282;
Bj66 = 0.001292;
Bj67 = 0.9948;

Beta1m1 = (Bj11*lambda)/((wj11+lambda)^2);
Beta2m1 = (Bj12*lambda)/((wj12+lambda)^2);
Beta1m6 = (Bj61*lambda)/((wj61+lambda)^2);
Beta2m6 = (Bj62*lambda)/((wj62+lambda)^2);
Beta3m6 = (Bj63*lambda)/((wj63+lambda)^2);
Beta4m6 = (Bj64*lambda)/((wj64+lambda)^2);
Beta5m6 = (Bj65*lambda)/((wj65+lambda)^2);
Beta6m6 = (Bj66*lambda)/((wj66+lambda)^2);

LB1 = Beta1m6;
LB2 = LB1+Beta2m6;
LB3 = LB2+Beta3m6;
LB4 = LB3+Beta4m6;
LB5 = LB4+Beta5m6;
LB6 = LB5+Beta6m6;

for t=0:0.1:1
    Im1 = (exp(wj11*t)/(l+Beta1m1))+(exp(wj12*t)/(l+Beta2m1));
    I1m6 = (exp(wj61*t)/LB1);
    I2m6 = (exp(wj62*t)/LB2);
    I3m6 = (exp(wj63*t)/LB3);
    I4m6 = (exp(wj64*t)/LB4);
    I5m6 = (exp(wj65*t)/LB5);
    I6m6 = (exp(wj66*t)/LB6);
    Im6 = I1m6+I2m6+I3m6+I4m6+I5m6+I6m6;
end 

disp(Im1)
disp(Im6)
plot(Im1,'LineWidth',2);
hold on
plot(Im6,'Linewidth',2)

[Chuguang Pan]

The values of Im1 and Im6 in your for loop are reassigned repeatly, so that you get the scalar in the last loop. The plot function can not plot a standalone scalar value.

[Zachary]

I'm sorry, I'm confused. Why can't MATLAB take simplified values (with one variable) and plot them between a range?

Answer 1

[Image Analyst]

You need to index Im1 and Im6. Otherwise you're just overwriting a single number in your loop and not creating a vector of several values that can be plotted as a function of t. See corrected code below. Adapt as needed.

% Demo by Image Analyst.
% Initialization steps.
clc;    % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);

Beginning to run LiveEditorEvaluationHelperEeditorId.m ...

close all;  % Close all figures (except those of imtool.)
clearvars;
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 16;
lineWidth = 2;
markerSize = 30;
l = 0.0001;
lambda = 0.405;
% syms tIndex;
wj11 = 0;
wj12 = -79.077;
wj61 = 0;
wj62 = -0.014533;
wj63 = -0.0682;
wj64 = -0.1947;
wj65 = -1.023;
wj66 = -2.896;
wj67 = -79.4;
Bj11 = 0.00097;
Bj12 = 0.99903;
Bj61 = Bj11;
Bj62 = 0.000091;
Bj63 = 0.000664;
Bj64 = 0.000901;
Bj65 = 0.001282;
Bj66 = 0.001292;
Bj67 = 0.9948;
Beta1m1 = (Bj11*lambda)/((wj11+lambda)^2);
Beta2m1 = (Bj12*lambda)/((wj12+lambda)^2);
Beta1m6 = (Bj61*lambda)/((wj61+lambda)^2);
Beta2m6 = (Bj62*lambda)/((wj62+lambda)^2);
Beta3m6 = (Bj63*lambda)/((wj63+lambda)^2);
Beta4m6 = (Bj64*lambda)/((wj64+lambda)^2);
Beta5m6 = (Bj65*lambda)/((wj65+lambda)^2);
Beta6m6 = (Bj66*lambda)/((wj66+lambda)^2);
LB1 = Beta1m6;
LB2 = LB1+Beta2m6;
LB3 = LB2+Beta3m6;
LB4 = LB3+Beta4m6;
LB5 = LB4+Beta5m6;
LB6 = LB5+Beta6m6;
t = 0:0.1:1

t = 1×11

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

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for tIndex = 1 : numel(t)
    this_t = t(tIndex); % Get this particular value of t from the vector of t values.
    % Assign this particular value of Im1.  Need to give it the index so it
    % goes into the proper location of the vector.
    Im1(tIndex) = (exp(wj11*this_t)/(l+Beta1m1))+(exp(wj12*this_t)/(l+Beta2m1));
    I1m6 = (exp(wj61*this_t)/LB1);
    I2m6 = (exp(wj62*this_t)/LB2);
    I3m6 = (exp(wj63*this_t)/LB3);
    I4m6 = (exp(wj64*this_t)/LB4);
    I5m6 = (exp(wj65*this_t)/LB5);
    I6m6 = (exp(wj66*this_t)/LB6);
    % Assign this particular value of Im6.  Need to give it the index so it
    % goes into the proper location of the vector.
    Im6(tIndex) = I1m6+I2m6+I3m6+I4m6+I5m6+I6m6;
end 
disp(Im1)

  Columns 1 through 6
          6447.75687139828          403.016364430728          400.792505741751          400.791687584634          400.791687283634          400.791687283523
  Columns 7 through 11
          400.791687283523          400.791687283523          400.791687283523          400.791687283523          400.791687283523

disp(Im6)

  Columns 1 through 6
          1208.32551171607          1181.20888523427          1159.07727742499          1140.78598141995          1125.46827162041          1112.46645460124
  Columns 7 through 11
           1101.2801646105          1091.52757665354          1082.91629725429          1075.22150683602          1068.26953695826

plot(t, Im1, 'r.-', 'LineWidth', lineWidth, 'MarkerSize', markerSize);
hold on
plot(t, Im6, 'b.-',  'LineWidth', lineWidth, 'MarkerSize', markerSize)
grid on;
xlabel('t', 'FontSize', fontSize);
ylabel('Value of Im1 or Im6', 'FontSize', fontSize);
legend('Im1', 'Im6');

[Image Analyst]

Or, the more MATLABy way of doing it, you can do it vectorized like Star showed you. That's actually how most of us would do it. I just showed you the for loop way because that's how you started it.

Answer 2

[Star Strider]

You do not need the loop.

Just usee vectorisation —

l = 0.0001;
lambda = 0.405;
syms t;
wj11 = 0;
wj12 = -79.077;
wj61 = 0;
wj62 = -0.014533;
wj63 = -0.0682;
wj64 = -0.1947;
wj65 = -1.023;
wj66 = -2.896;
wj67 = -79.4;
Bj11 = 0.00097;
Bj12 = 0.99903;
Bj61 = Bj11;
Bj62 = 0.000091;
Bj63 = 0.000664;
Bj64 = 0.000901;
Bj65 = 0.001282;
Bj66 = 0.001292;
Bj67 = 0.9948;
Beta1m1 = (Bj11*lambda)/((wj11+lambda)^2);
Beta2m1 = (Bj12*lambda)/((wj12+lambda)^2);
Beta1m6 = (Bj61*lambda)/((wj61+lambda)^2);
Beta2m6 = (Bj62*lambda)/((wj62+lambda)^2);
Beta3m6 = (Bj63*lambda)/((wj63+lambda)^2);
Beta4m6 = (Bj64*lambda)/((wj64+lambda)^2);
Beta5m6 = (Bj65*lambda)/((wj65+lambda)^2);
Beta6m6 = (Bj66*lambda)/((wj66+lambda)^2);
LB1 = Beta1m6;
LB2 = LB1+Beta2m6;
LB3 = LB2+Beta3m6;
LB4 = LB3+Beta4m6;
LB5 = LB4+Beta5m6;
LB6 = LB5+Beta6m6;
% for t=0:0.1:1
    t=0:0.1:1;
Im1 = (exp(wj11*t)/(l+Beta1m1))+(exp(wj12*t)/(l+Beta2m1));
I1m6 = (exp(wj61*t)/LB1);
I2m6 = (exp(wj62*t)/LB2);
I3m6 = (exp(wj63*t)/LB3);
I4m6 = (exp(wj64*t)/LB4);
I5m6 = (exp(wj65*t)/LB5);
I6m6 = (exp(wj66*t)/LB6);
Im6 = I1m6+I2m6+I3m6+I4m6+I5m6+I6m6;
% end 
disp(Im1)

   1.0e+03 *

    6.4478    0.4030    0.4008    0.4008    0.4008    0.4008    0.4008    0.4008    0.4008    0.4008    0.4008

disp(Im6)

   1.0e+03 *

    1.2083    1.1812    1.1591    1.1408    1.1255    1.1125    1.1013    1.0915    1.0829    1.0752    1.0683

plot(Im1,'LineWidth',2);
hold on
plot(Im6,'Linewidth',2)

.