combining different row vectors of different lengths

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Adil Saeed 2022-8-15

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https://ww2.mathworks.cn/matlabcentral/answers/1779665-combining-different-row-vectors-of-different-lengths

评论： Adil Saeed 2022-8-16

t1 = 30;
t2 = 15;
t3 = 12;
t4 = 2.4;
t5 = 2.1428;
t6 = 2.5;
v1 = 0:t1:900-t1;
v2 = 900:t2:1800-t2;
v3 = 1800:t3:2700-t3;
v4 = 2700:t4:3600-t4;
v5 = 3600:t5:4500-t5;
v6 = 4500:t6:5400-t6;

I am wondering if i can combine all these 'v' vectors into one, whilst keeping the conditions set. So at 900, the values increase by t2 rather than t1 and at 1800 the values increase by t3 rather than t2 etc.

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Answer 1

Image Analyst 2022-8-15

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https://ww2.mathworks.cn/matlabcentral/answers/1779665-combining-different-row-vectors-of-different-lengths#answer_1026730

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vout = [v1,v2,v3,v4,v5,v6];

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Adil Saeed 2022-8-15

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can you help me out with something using this code if i explain my model? above i have shown a value of how often a recording/impact is taken (every t value) based on what time period it is in intervals of 900 s. (0 - 5400 s). in my current model this was a fixed number of impacts throughout the whole event, however now things will change according to what period it is in, such as a new position, in this case a marine mammal will be in. I have tried encorporating this however as you can see for the function s, the value for t will not be as shown here as 30, but the value for t, based on how long in the walk the mammal is in. As will the value for t on the line starting RL(i,2:end), however this line does not change the results, im hoping it is due this t value cahnge required.

clc;
clear;
x0 = 0;
y0 = 0;
Sr = [x0 y0];               %Source coordinates
IL = 160;                   %Impact Level
v = 2.35;                   %Speed
t = 30;                      %Time between each impact
s = v*t;                    %Distance
T = 5400;                   %Total Time
iter = 1320;                %number of Positions / Impacts / Recordings
TV = [0:30:900-30, 900:15:1800-15, 1800:12:2700-12, 2700:2.4:3600-2.4, 3600:2.1428:4500-2.1428, 4500:2.5:5400-2.5]; %Time vector between each impact
X = zeros(iter,1);
Y = zeros(iter,1);
RL = zeros(iter,1);
% starting condition - random position start
Z = [randi([-10 10]) randi([-10 10])];
%Z = [5 2];
d = sqrt((Z(1)-x0)^2+(Z(2)-y0)^2); % Pythagoras Theorem for distance between the Source and initial Reciever points
for i = 1:iter
        SL = 212 + 20*log10(10);    %single source value that has been kept constant throughtout
        
        % assign position coordinates
        x = Z(1);
        y = Z(2);
        
        % save current position
        X(i) = x;
        Y(i) = y;
        
        %Prpoagation Loss
        s1 = sqrt((x-x0)^2+(y-y0)^2); % Pythagoras Theorem for distance between the 2 (Source and Reciever) points
        theta = atan2d(y,x);
        TL = 20*log10(s1);  %Transmission Loss
        RL(i) = SL - TL; % Receive Level
        RL(i,2:end) = RL(i,2:end) + 10.*log10(t);           %encorporate the energy exposure at the position for t(s), (assumption)
        r = d + (i-1)*s;
        
        if RL(i) > IL
        %Update for position based on random biased flee direction
        x = Z(1) + s*cosd(theta); % use cosd for angle in degrees
        y = Z(2) + s*sind(theta); % use sind for angle in degrees
        Z = [x y]; % update current location
        else
        %Update for position based on random direction
        alpha = 360*rand;
        x = Z(1) + s*cosd(theta + alpha); % use cosd for angle in degrees
        y = Z(2) + s*sind(theta + alpha); % use sind for angle in degrees
        Z = [x y]; % update current location
        end
    
    % save result
    X(i) = x;
    Y(i) = y;
end
%RECEIVE LEVEL MODEL
figure
set(plot(TV,RL,'.'),'markersize',3)
hold on;
set(plot(TV,SL,'.'),'markersize',3)
xlabel('Time (s)')
ylabel('Decibels (dB)')
legend({'Individual Strike Recieve Level (dB re μPa^2s)','Individual Strike Source Level (dB re μPa^2s-m)'},'Location','east')

Apologies for the long winded code

Adil Saeed 2022-8-15

within my loop currently, 's' has remained constant, due to t being constant. However now i would like 't' to change based after a certain number of impacts / positions or the time period, which ive tried using the 'TV' vector. so during 0 - 900 s, impact occurs every 30 s, therefore t would be 30 within this range in my loop, and this would provide 30 positions all a distance of 's'. The next interval is 900 - 1800 s, impact occurs every 15 s therefore t would be 15 within this range in my loop and i would like 's' to change as this would be from 30 - 90 positions and so on until 5400 s or 1320 impact / positions. the iter demonstrates the total number of impacts / positions.

So i need my current loop to be modified to change t, according to what position / iter it is curently at, based on what I've tried using as the 'TV' vector. I've tried my best to explain it, if you think my methodology is completely wrong let me know.

Adil Saeed 2022-8-16

在 MATLAB Online 中打开

I think i found a way to solve it, would you mind just double checking it, the code might make it easier for you to understand what i was trying to do

clc, clear;
x0 = 0; y0 = 0;
Sr = [x0 y0];               %Source coordinates
IL = 160;                   %Impact Level
v = 2.35;                   %Speed
T = 5400;                   %Total Time
iter = 1320;                %number of Positions / Impacts / Recordings
TV = [0:30:900-30, 900:15:1800-15, 1800:12:2700-12, 2700:2.4:3600-2.4, 3600:2.1428:4500-2.1428, 4500:2.5:5400-2.5]; %Time vector between each impact
X = zeros(iter,1);
Y = zeros(iter,1);
RL = zeros(iter,1);
% starting condition - random position start
%Z = [randi([-10 10]) randi([-10 10])];
Z = [5 2];
d = sqrt((Z(1)-x0)^2+(Z(2)-y0)^2); % Pythagoras Theorem for distance between the Source and initial Reciever points
for i = 1:iter
    if 0<i && i<=30
        t = 30;
    elseif 30<i && i<=90
        t = 15;
    elseif 90<i && i<=165
        t = 12;
    elseif 165<i && i<=540
        t = 2.4;
    elseif 540<i && i<=960
        t = 2.1428;
    elseif 960<i && i<=1320
        t = 2.5;
    end
    
    s = v*t;
    SL = 212 + 20*log10(10);    %single source value that has been kept constant throughtout
    
    % assign position coordinates
    x = Z(1);
    y = Z(2);
    
    % save current position
    X(i) = x;
    Y(i) = y;
    
    %Prpoagation Loss
    s1 = sqrt((x-x0)^2+(y-y0)^2); % Pythagoras Theorem for distance between the 2 (Source and Reciever) points
    theta = atan2d(y,x);
    TL = 20*log10(s1);  %Transmission Loss
    RL(i) = SL - TL; % Receive Level
    %RL(i) = RL(i) + 10.*log10(t);           %encorporate the energy exposure at the position for t(s), (assumption)
    r = d + (i-1)*s;
    
    if RL(i) > IL
        %Update for position based on random biased flee direction
        x = Z(1) + s*cosd(theta); % use cosd for angle in degrees
        y = Z(2) + s*sind(theta); % use sind for angle in degrees
        Z = [x y]; % update current location
    else
        %Update for position based on random direction
        alpha = 360*rand;
        x = Z(1) + s*cosd(theta + alpha); % use cosd for angle in degrees
        y = Z(2) + s*sind(theta + alpha); % use sind for angle in degrees
        Z = [x y]; % update current location
    end
    
    % save result
    X(i) = x;
    Y(i) = y;
end
%RECEIVE LEVEL MODEL
figure
set(plot(TV,RL,'.'),'markersize',3)
hold on;
set(plot(TV,SL,'.'),'markersize',3)
xlabel('Time (s)')
ylabel('Decibels (dB)')
legend({'Individual Strike Recieve Level (dB re μPa^2s)','Individual Strike Source Level (dB re μPa^2s-m)'},'Location','east')

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combining different row vectors of different lengths

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