I am making a "movie" where the dots should move each X time
Here is the code (not copy paste so dont fix typos)
loop:
scatter(x,y,[],colors)
axies (a b c d)
pause(0.01);
end loop;
This is working great, but how can i add a LINE for the X axise (1:140)
At height 150?
I tired hold on but it just make a mess... or what is the command to clean grough when its in hold on?
Could this work for you?
N = 1000;
X = 1:N;
M = 160;
Y = randi(M, N);
figure
for i = 1:N
x = X(i);
y = Y(i);
scatter(x,y,[])
hold on
line([1 N], [150 150])
hold off
axis([1 N 0 200])
pause(0.01);
end
Related
i am doing my project on graph extraction in hand written word in this i divided a binary image into equal segments using
C = (width of image image / 10 ) and R = (height of image image / 10 ) word image divided into 'C x R' segments of equal size, For each
segment sij (i = 1, . . . , C; j = 1, . . . , R) a node is inserted into the resulting graph and labelled by the (x, y)-coordinates of the center of mass (xm, ym) Formally, we compute the number of foreground pixel in segment sij, while xw and yw denote the x- and y-coordinates of the foreground pixels in sij. If a segment does not contain any foreground pixel, no centre of mass can be determined and thus no node is created for this segment.
in my code i compute the center of mass in each segments but i want to connect the each node on the image please help to solve this problem
clc;
clear all;
close all;
X=imread('math.jpg');
imfinfo('math.jpg')
figure,imshow(X)
b = imresize(X,[100,100]);
si = size(b,1);
sj = size(b,2);
figure;imshow(b);
% Binarization
th = graythresh(b);
I = im2bw(b,th);
w = 5;
h = 5;
c=si/w;
r=sj/h;
% Skeletonised
kl=bwmorph(~I,'thin',inf);
figure,imshow(kl)
R(:,:)=kl(:,:);
I=1;
U1=w;
J=1;
U2=h;
E=1;
for i=1:r
for j=1:c
B(I:U1,J:U2)=R(I:U1,J:U2);
[x,y]=find(B==1);
XX=mean(x);
YY=mean(y);
XXX(E)=CX;
YYY(E)=CY;
T(I:U1,J:U2)=B(I:U1,J:U2);
J=J+w;
U2=U2+h;
E=E+1;
clear B x y
end
I=I+w;
U1=U1+h;
J=1;
U2=h;
end
imshow(R)
hold on
plot(XX,YY, 'g*');
hold off
in my code i am getting center of mass of foreground pixels in each segment
this is my output
output of my code
help me add the plotted point on image as a node to resulting graph
Edited,
input image
clc;
clear all;
close all;
X=imread('math.jpg');
imfinfo('math.jpg')
figure,imshow(X)
b = imresize(X,[100,100]);
si = size(b,1);
sj = size(b,2);
%figure;imshow(b);
% Binarization
th = graythresh(b);
I = im2bw(b,th);
%Skeletonised
kl=bwmorph(~I,'thin',inf);
figure,imshow(kl)
R(:,:)=kl(:,:);
%grid size
t1=10;
D=100;
I=1;
U1=t1;
J=1;
U2=t1;
E=1;
t2=D/t1;
%Z=1;
for i=1:t2
for j=1:t2
B(I:U1,J:U2)=R(I:U1,J:U2);
[x,y]=find(B==1);
CX=mean(x);
CY=mean(y);
CXXX(E)=CX;
CYYY(E)=CY;
CXX(i,j)=CX;
CYY(i,j)=CY;
T(I:U1,J:U2)=B(I:U1,J:U2);
J=J+t1;
U2=U2+t1;
E=E+1;
clear B x y
end
I=I+t1;
U1=U1+t1;
J=1;
U2=t1;
end
%plot and grid
figure,imshow(R)
hold on
M = size(R,1);
N = size(R,2);
a=t1;
b=t1;
for k = 1:a:M
x = [1 N];
y = [k k];
plot(x,y,'Color','white');
set(findobj('Tag','MyGrid'),'Visible','on')
end
for k = 1:b:N
x = [k k];
y = [1 M];
plot(x,y,'Color','white');
set(findobj('Tag','MyGrid'),'Visible','on')
end
plot(CXX,CYY, 'g*');
hold off
Sir please try this edited code.
If I understand your question correctly, you want to draw lines between the green stars. This can been done as follows:
plot(CYY(isfinite(CYY)),CXX(isfinite(CYY)), 'g*-');
I removed the invalid values using logical indexing, otherwise not all the connections are drawn.
I updated the question to clarify it more. Here is a graph:
For the curve in the attached photo, I hope to draw the curve. I have its equation and it is after simplification will be like this one
% Eq-2
(b*Y* cos(v) + c - k*X*sin(v))^2 + ...
sqrt(k*X*(cos(v) + 1.0) + b*Y*sin(v))^2) - d = 0.0
Where:
v = atan((2.0*Y)/X) + c
and b, c, d and k are constants.
from the attached graph,
The curve is identified in two points:
p1 # (x=0)
p2 # (y=0)
I a new on coding so accept my apologize if my question is not clear.
Thanks
So, after your edit, it is a bit more clear what you want.
I insist that your equation needs work -- the original equation (before your edit) simplified to what I have below. The curve for that looks like your plot, except the X and Y intercepts are at different locations, and funky stuff happens near X = 0 because you have numerical problems with the tangent (you might want to reformulate the problem).
But, after checking your equation, the following code should be helpful:
function solve_for_F()
% graininess of alpha
N = 100;
% Find solutions for all alphae
X = zeros(1,N);
options = optimset('Display', 'off');
alpha = linspace(0, pi/2, N);
x0 = linspace(6, 0, N);
for ii = 1:numel(alpha)
X(ii) = fzero(#(x)F(x, alpha(ii)), x0(ii), options);
end
% Convert and make an X-Y plot
Y = X .* tan(alpha);
plot(X, Y,...
'linewidth', 2,...
'color', [1 0.65 0]);
end
function fval = F(X, alpha)
Y = X*tan(alpha);
% Please, SIMPLIFY in the future
A = 1247745517111813/562949953421312;
B = 4243112111277797/4503599627370496;
V = atan2(2*Y,X) + A;
eq2 = sqrt( (5/33*( Y*sin(V) + X/2*(cos(V) + 1) ))^2 + ...
(5/33*( Y*cos(V) - X/2* sin(V) ))^2 ) - B;
fval = eq2;
end
Results:
So, I was having fun with this (thanks for that)!
Different question, different answer.
The solution below first searches for the constants causing the X and Y intercepts you were looking for (p1 and p2). For those constants that best fit the problem, it makes a plot, taking into account numerical issues.
In fact, you don't need eq. 1, because that's true always for any curve -- it's just there to confuse you, and problematic to use.
So, here it is:
function C = solve_for_F()
% Points of interest
px = 6;
py = 4.2;
% Wrapper function; search for those constants
% causing the correct X,Y intercepts (at px, py)
G = #(C) abs(F( 0, px, C)) + ... % X intercept at px
abs(F(py, 0, C)); % Y intercept at py
% Initial estimate, based on your original equation
C0 = [5/33
1247745517111813/562949953421312
4243112111277797/4503599627370496
5/66];
% Minimize the error in G by optimizing those constants
C = fminsearch(G, C0);
% Plot the solutions
plot_XY(px, py, C);
end
function plot_XY(xmax,ymax, C)
% graininess of X
N = 100;
% Find solutions for all alphae
Y = zeros(1,N);
X = linspace(0, xmax, N);
y0 = linspace(ymax, 0, N);
options = optimset('Display', 'off',...,...
'TolX' , 1e-10);
% Solve the nonlinear equation for each X
for ii = 1:numel(X)
% Wrapper function for fzero()
fcn1 = #(y)F(y, X(ii), C);
% fzero() is probably the fastest and most intuitive
% solver for this problem
[Y(ii),~,flag] = fzero(fcn1, y0(ii), options);
% However, it uses an algorithm that easily diverges
% when the function slope is large. For those cases,
% solve with fminsearch()
if flag ~= 1
% In this case, the minimum of the absolute value
% is searched for (which should be zero)
fcn2 = #(y) abs(fcn1(y));
Y(ii) = fminsearch(fcn2, y0(ii), options);
end
end
% Now plot the X,Y solutions
plot(X, Y,...
'linewidth', 2,...
'color', [1 0.65 0]);
xlabel('X'), ylabel('Y')
axis([0 xmax+.1 0 ymax+.1])
end
function fval = F(Y, X, C)
% Unpack constants
b = C(1); d = C(3);
c = C(2); k = C(4);
% pre-work
V = atan2(2*Y, X) + c;
% Eq. 2
fval = sqrt( (b*Y*sin(V) + k*X*(cos(V) + 1))^2 + ...
(b*Y*cos(V) - k*X* sin(V) )^2 ) - d;
end
When I execute this plot function trying to plot my data as a solid red line it will not plot anything.
plot(1:n, exp(x), '-r')
However, if I change the specification from a solid red line to a green line of circles still using the exact same data as so,
plot(1:n, exp(x), 'og')
it will plot! Why??
Here is all the code if needed.
clear all;
close all;
fprintf('\n\nJustin White Th-9\n\n')
x = input('Input the value of x to be approximated: ');
se = input('Input the target approximate perecent relative error, se: ');
[apre, macexp, n] = f_macexpF15(x, se);
macexp = macexp(1:end-1);
plotyy( 1:n, macexp, 1:n, apre);
hold on;
plot(1:n, exp(x), '-r')
And function it calls here
function[apre, macexp, n] = f_macexpF15(x, se)
fprintf('\nJustin White Th-9\n')
apre = 100*ones(1,3);
ms = [36 22 10];
macexp(1) = 1;
j = 1;
n = 1;
%% comments
while apre >= se
macexp(j+1) = macexp(j) + x^j/factorial(j);
apre(j) = 100 * ((macexp(j+1)-macexp(j))/macexp(j+1));
j = j + 1;
n = n + 1;
end
n = n - 1;
end
Thanks in advance
Easy, 1:n is a vector of length n, whereas x is only a scalar value if not entered correctly. So first of all check whether or not both vectors (1:n and x) are of same size.
Why? If you have two entries for the plot command, and one entry is a vector and the other is a scalar, then MATLAB treats that as if you entred n different plot commands (n for the length of the vector).
I need the following code to plot the range of values of C(i) against the values of x. So based on the code at the x = 1, I need C(1), at x = 2, C(2) and so on... A simple problem Im sure, please help!
clear all; clc;
n = 15
x = 1:(n-1)
T = 500;
D = T./(n-x)
for i=1:13
C(i) = D(i+1) - D(i)
end
plot(x, C(i), 'rx')
I guess what you want is this,
clear
clc
close all
n = 15;
x = 1:(n-1);
T = 500;
D = T./(n-x);
C = zeros(length(x) - 1, 1);
for i=1:13
C(i) = D(i+1) - D(i);
end
figure, plot(C, 'rx')
It is better to preallocate the C variable, so you can plot it then.
The C(i) only gave you the last number because after the for i is 13 and C(i)as you had it only gives you C in the 13th position.
Change:
plot(x, C(i), 'rx')
To:
plot(x(1:end-1), C, 'rx')
Actually, you could replace your for loop with this:
C = diff(D);
Which calculates the difference between consecutive elements.
I have a matlab function that contain some constant parameter, I want to draw that function, on say same figure, using hold on (probably) while changing the value of that constant.
This my code:
close all
clear all
clc
m = 5;
x = 1:1:10;
y = m*x + 10;
h1 = figure;
plot(x,y)
m = 10;
figure(h1);
hold on
plot(x,y,': r')
When I tried using this code, I got two lines coincident on each others; and it looks matlab just used last value for the parameter m how can I make it use different values.
I found some stuff here, but doesn't fulfill my needs.
Any suggestions?
You need to recalculate y as well:
m = 5;
x = 1:1:10;
y = m*x + 10;
h1 = figure;
plot(x,y); hold on;
m = 10;
y = m*x + 10;
figure(h1);
plot(x,y,': r')
Or create an anonymous function:
x = 1:1:10;
f = #(m) m*x + 10;
%// and then:
h1 = figure;
plot(x,f(5) ); hold on;
plot(x,f(10),': r');
Currently, you're only updating m but you also have to calculate y again. This is why it plots exactly the same y (i.e. m is still 5) function when you issue the second plot.
You might want to use a simple for loop for that, like:
m = 5;
x = 1:1:10;
figure;
hold on;
for m=1:1:10
y = m*x + 10;
plot(x,y,': r')
end
In addition to the short answer - improving the plot..
%% Data Preparations
x = 1:10;
ms = 3; % number of different slopes
%% Graph Preparations
hold on;
% Prepare the string cell array
s = cell(1, ms);
% Handle storage
h = zeros(1, ms);
% Plot graphs
for m=1:ms
y = m*x + 10;
h(m)= plot(x,y,'Color',[1/m rand() rand()]);
s{m} = sprintf('Plot of y(m=%d)', m);
end
% Plot all or select the plots to include in the legend
ind = [ms:-1:1] .* ones(1,ms); % plot all
%ind = [ 1 3 4 ]; % plot selected
% Create legend for the selected plots
legend(h(ind), s{ind});
Additional advice: When working with MATLAB and you try to improve the performance of your code, you shoud try to avoid using for-loops since MATLAB is MATrix manipulation and that's what it can do best. Ones you've taken this philosophy in, you'll create the most beautiful code one-liners! ;)
This script is an adoption of Steve Lord's post.