Having each iteration of nested loop plot on graph

Question

Mabin 2023-2-10

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1910040-having-each-iteration-of-nested-loop-plot-on-graph

编辑： Tushar Behera 2023-2-10

I have a test script of a much larger script for one nested loop. The nested loop uses 3 different vectorized variables to find a Radius, then using the same variables and the new radius, determine a value. The value is summed for each possible combination of x and y for a given z. I wish to plot that summed value, the the loop will return to z and pick a new z, where the sum is reset. Once each z has been used, the plot should show the summed value at each z recorded on a single plot. When I use the loop, I am only getting the final value of sigma, and nothing plotted. Can someone figure out why my nested loop is failing?

clear;clc;

gamma = 95;

zwater = 0;

H = 10;

TYP = 1;

x = 8;

v = 0.49;

array = 2;

arraysize = 6;

Q = 250;

Q = (Q/array^2);

nax = array;

nay = array;

sum =0;

xmin = x - arraysize/2;

xmax = x + arraysize/2;

yleft = -(arraysize/2);

yright = (arraysize/2);

z = 0:0.1:H;

xa = linspace(xmin+(1/(2*array)*arraysize),xmax-(arraysize/(2*array)),nax);

ya = linspace(yleft+(1/(2*array)*arraysize),yright-(arraysize/(2*array)),nay);

for zii = z

sum =0;

for xii = xa

for yii = ya

R = sqrt(xii^2+yii^2+zii^2);

sigprimeh = ((Q/(R*pi))*((3*zii*xii^2)/R^3)*((R*(1-2*v))/(R+zii)));

sum = sum +sigprimeh;

figure()

end

plot(sigprimeh,z)

title('Stress Due to Surcharge Load')

xlabel('\sigma`h (ksf)');

ylabel('Depth "z"(ft)');

set(gca,'YDir','reverse')

hold on

end

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Answer 1

Tushar Behera 2023-2-10

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1910040-having-each-iteration-of-nested-loop-plot-on-graph#answer_1168120

编辑：Tushar Behera 2023-2-10

在 MATLAB Online 中打开

Hi Mabin,

I assume you want to know why your code is not performing as you had expected.

Your code has a problem since you calculate the "sigprimeh" value inside the innermost loop, overwriting it after each iteration and only charting the final value. After computing the total for each "zii", you must relocate the assignment statement outside the innermost loop in order to plot the cumulative sum for each "zii" value. Also you should use an array to store the values of "sigmaprimeh" as that will preserve all the calculated values. For example:

clear;
clc;
gamma = 95;
zwater = 0;
H = 10;
TYP = 1;
x = 8;
v = 0.49;
array = 2;
arraysize = 6;
Q = 250;
Q = (Q/array^2);
nax = array;
nay = array;
xmin = x - arraysize/2;
xmax = x + arraysize/2;
yleft = -(arraysize/2);
yright = (arraysize/2);
z = 0:0.1:H;
sigma_h = zeros(1,length(z)); % Preallocate memory for sigma_h
xa = linspace(xmin+(1/(2*array)*arraysize),xmax-(arraysize/(2*array)),nax);
ya = linspace(yleft+(1/(2*array)*arraysize),yright-(arraysize/(2*array)),nay);
for ii = 1:length(z)
    sum =0;
    for xii = xa
        for yii = ya
            R = sqrt(xii^2+yii^2+z(ii)^2);
            sigprimeh = ((Q/(R*pi))*((3*z(ii)*xii^2)/R^3)*((R*(1-2*v))/(R+z(ii))));
            sum = sum +sigprimeh;
        end
    end
    sigma_h(ii) = sum;
end
plot(sigma_h,z)
title('Stress Due to Surcharge Load')
xlabel('\sigma`h (ksf)');
ylabel('Depth "z"(ft)');
set(gca,'YDir','reverse')