I have this piece of code and what i'm trying to do is to fill this function plot that is made with timeseries. I tried full and area methods, but didn't have any success to implement them. I also tried to plot using TP1out to plot instead of TP1, but doing this i lose my ZOH interpolation and the graph become linear. If someone have an idea how to solve this i would be thankful.
TP1out = [1 0 0 1 0];
time = 0:4;
TP1 = timeseries(TP1out,time,'name','task 1');
TP1.DataInfo.Interpolation = tsdata.interpolation('zoh');
plot(TP1), grid on
axis([0 4 0 1.5])
I know it's stupid, but i tried many stuff, like:
>> area(TP1)
Undefined function 'real' for input arguments of type
'timeseries'.
Error in xychk (line 48)
x = real(y); y = imag(y);
Error in area (line 45)
[msg,x,y] = xychk(args{1:nargs},'plot');
>> area(time,TP1)
Error using specgraph.areaseries/set
Array must be numeric or logical.
Error in specgraph.areaseries (line 40)
set(h,args{:})
Error in area (line 83)
h = [h
specgraph.areaseries('YData',datachk(y(:,k)),
...
>> area(time,TP1.Data)
Error using area (line 46)
Inputs must be 2-D.
Related
I am new to MATLAB and new to image processing.
I am going to find the contour of an image, so
leaf = imread('images\leaf.jpg')
SE = [1 1 1
1 1 1
1 1 1]
figure
imshow(leaf)
title("leaf_origin")
erosed_leaf = imerode(leaf,SE);
Contour = double(leaf) - double(erosed_leaf)
Contour=~Contour
figure
imshow(Contour)
This gives me an error while running imshow
Error using images.internal.imageDisplayValidateParams>validateCData (line 119)
If input is logical (binary), it must be two-dimensional.
Error in images.internal.imageDisplayValidateParams (line 27)
common_args.CData = validateCData(common_args.CData,image_type);
Error in images.internal.imageDisplayParseInputs (line 78)
common_args = images.internal.imageDisplayValidateParams(common_args);
Error in imshow (line 241)
images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});
if I remove ~ in front of contour, it works but gives incorrect output. Can anybody give me any hint about the error?
erosed_leaf = imerode(leaf,SE);
contour = double(leaf) - double(erosed_leaf);
contour = double(~contour);
figure();
imshow(contour);
The function is as expected:
%% plot 3D plot with true color marker
plot_Lab(4,Lab,1,'',12,0);
plot_Lab(mode,Lab,createnewfig,markercolor,markersize,storeme)
% This function visualizes several different CIE-Lab_plot plots from
% CIE-Lab coordinate data in 'Lab'.
I enter this:
plot_Lab(4,[45.9470,1.5130,5.2120],1,'',12,0);
and get the following error messages
Error using lab2xyz (line 25)
Incorrect number of columns in LAB data.
Error in applycform (line 88)
out = c.c_func(columndata, cdata{:});
Error in applycformsequence (line 11)
out = applycform(out, cforms{k});
Error in applycform (line 88)
out = c.c_func(columndata, cdata{:});
Error in plot_Lab (line 68)
RGB = applycform(Lab',cform);
Does anyone know where I got it wrong? Please help.
plot_Lab is not a built-in function. Therefore you are supposed to provide its code or link, so one could follow you.
According to the link,
% Lab [3 x n] -> Lab coordinates of n datapoints
Lab is supposed to be 3 x n. What you are provided is 1 x 3. So, you probably need to transpose it:
plot_Lab(4, [45.9470,1.5130,5.2120].', 1, '', 12, 0);
I have code that, when run, should correctly use Lagrange Multipliers to find the maximum/minimum of a function here:
clear all
syms x y L;
f = x^4+2*y^4;
g = x^2+5*y^2+2*y^2-10;
firstpart=jacobian(f,[x y])-L*jacobian(g,[x y]);
[Lsoln,xsoln,ysoln]=solve(firstpart,x^2+5*y^2+2*y^2-10);
subs(f,{x,y},{xsoln,ysoln})
% The coordinates that correspond with the greatest and smallest values
% above are the maximum and minimum, respectively.
However, when I run it, I get four errors:
Error using sym.getEqnsVars>checkVariables (line 92) The second
argument must be a vector of symbolic variables.
Error in sym.getEqnsVars (line 62)
checkVariables(vars);
Error in solve>getEqns (line 450) [eqns, vars] =
sym.getEqnsVars(argv{:});
Error in solve (line 225) [eqns,vars,options] = getEqns(varargin{:});
Could anyone help?
You are passing two equations as individual arguments zu solve, that is not possible. You have to put both into an array
[Lsoln,xsoln,ysoln]=solve([firstpart,x^2+5*y^2+2*y^2-10] );
i have some experimental data and a theoretical model which i would like to try and fit. i have made a function file with the model - the code is shown below
function [ Q,P ] = RodFit(k,C )
% Function file for the theoretical scattering from a Rod
% R = radius, L = length
R = 10; % radius in Å
L = 1000; % length in Å
Q = 0.001:0.0001:0.5;
fun = #(x) ( (2.*besselj(1,Q.*R.*sin(x)))./...
(Q.*R.*sin(x)).*...
(sin(Q.*L.*cos(x)./2))./...
(Q.*L.*cos(x)./2)...
).^2.*sin(x);
P = (integral(fun,0,pi/2,'ArrayValued',true))*k+C;
end
with Q being the x-values and P being the y-values. I can call the function fine from the matlab command line and it works fine e.g. [Q,P] = RodFit(1,0.001) gives me a result i can plot using plot(Q,P)
But i cannot figure how to best find the fit to some experimental data. Ideally, i would like to use the optimization toolbox and lsqcurvefit since i would then also be able to optimize the R and L parameters. but i do not know how to pass (x,y) data to lsqcurvefit. i have attempted it with the code below but it does not work
File = 30; % the specific observation you want to fit the model to
ydata = DataFiles{1,File}.data(:,2)';
% RAdius = linspace(10,1000,length(ydata));
% LEngth = linspace(100,10000,length(ydata));
Multiplier = linspace(1e-3,1e3,length(ydata));
Constant = linspace(0,1,length(ydata));
xdata = [Multiplier; Constant]; % RAdius; LEngth;
L = lsqcurvefit(#RodFit,[1;0],xdata,ydata);
it gives me the error message:
Error using *
Inner matrix dimensions must agree.
Error in RodFit (line 15)
P = (integral(fun,0,pi/2,'ArrayValued',true))*k+C;
Error in lsqcurvefit (line 199)
initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});
Caused by:
Failure in initial user-supplied objective function evaluation. LSQCURVEFIT cannot continue.
i have tried i) making all vectors/matrices the same length and ii) tried using .* instead. nothing works and i am giving the same error message
Any kind of help would be greatly appreciated, whether it is suggestion regading what method is should use, suggestions to my code or something third.
EDIT TO ANSWER Osmoses:
A really good point but i do not think that is the problem. just checked the size of the all the vectors/matrices and they should be alright
>> size(Q)
ans =
1 1780
>> size(P)
ans =
1 1780
>> size(xdata)
ans =
2 1780
>> size([1;0.001]) - the initial guess/start point for xdata (x0)
ans =
2 1
>> size(ydata)
ans =
1 1780
UPDATE
I think i have identified the problem. the function RodFit works fine when i specify the input directly e.g. [Q,P] = RodFit(1,0.001);.
however, if i define x0 as x0 = [1,0.001] i cannot pass x0 to the function
>> x0 = [1;0.001]
x0 =
1.0000
0.0010
>> RodFit(x0);
Error using *
Inner matrix dimensions must agree.
Error in RodFit (line 15)
P = (integral(fun,0,pi/2,'ArrayValued',true))*k+C;
The same happens if i use x0 = [1,0.001]
clearly, matlab is interpreting x0 as input for k only and attempts to multiplay a vector of length(ydata) and a vector of length(x0) which obviously fails.
So my problem is that i need to code so that lsqcurvefit understands that the first column of xdata and x0 is the k variable and the second column of xdata and x0 is the C variable. According to the documentation - Passing Matrix Arguments - i should be able to pass x0 as a matrix to the solver. The solver should then also pass the xdata in the same format as x0.
Have you tried (that's sometimes the mistake) looking at the orientation of your input data (e.g. if xdata & ydata are both row/column vectors?). Other than that your code looks like it should work.
I have been able to solve some of the problems. One mistake in my code was that the objective function did not use of vector a variables but instead took in two variables - k and C. changing the code to accept a vector solved this problem
function [ Q,P ] = RodFit(X)
% Function file for the theoretical scattering from a Rod
% R = radius, L = length
% Q = 0.001:0.0001:0.5;
Q = linspace(0.11198,4.46904,1780);
fun = #(x) ( (2.*besselj(1,Q.*R.*sin(x)))./...
(Q.*R.*sin(x)).*...
(sin(Q.*L.*cos(x)./2))./...
(Q.*L.*cos(x)./2)...
).^2.*sin(x);
P = (integral(fun,0,pi/2,'ArrayValued',true))*X(1)+X(2);
with the code above, i can define x0 as x0 = [1 0.001];, and pass that into RodFit and get a result. i can also pass xdata into the function and get a result e.g. [Q,P] = RodFit(xdata(2,:));
Notice i have changed the orientation of all vectors so that they are now row-vectors and xdata has size size(xdata) = 1780 2
so i thought i had solved the problem completely but i still run into problems when i run lsqcurvefit. i get the error message
Error using RodFit
Too many input arguments.
Error in lsqcurvefit (line 199)
initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});
Caused by:
Failure in initial user-supplied objective function evaluation. LSQCURVEFIT cannot continue.
i have no idea why - does anyone have any idea about why Rodfit recieves to many input arguments when i call lsqcurvefit but not when i run the function manual using xdata?
I am trying to solve a problem (think excel "goal seek") where given a specific rate of return, matlab can solve for the variable "y" (which is used to multiply a matrix).
I've tried using fgoalattain (i don't understand it) and solve
here is the function which basically adds some arrays together to make a cashflow with y being a double. ppam_gen is a n*1 matrix. other_tot is a n*1 matrix.
down_pmt is a double.
function ansirr = cirr(y)
cf_gen_oth = y*ppam_gen + oth_tot
dp = [-down_pmt]
cashflow = [dp;cf_gen_oth]
ansirr = irr(cashflow)
%ansirr = irr([dp; y*ppam_gen + oth_tot])
end
x = fgoalattain(#cirr,0.001,.15,abs(.15))
does not work, the following error is given:
Error using roots (line 28)
Input to ROOTS must not contain NaN or Inf.
Error in irr (line 134)
coeff = roots(fliplr(cf(:,loop)')); % Find roots of polynomial
Error in ppa_model/cirr (line 139)
ansirr = irr(cashflow)
Error in goalcon (line 26)
f = feval(funfcn{3},x,varargin{:});
Error in
fgoalattain>#(y,varargin)feval(cfun{3},y,neqgoals,funfcn,confcn,WEIGHT,GOAL,x,errCheck,varargin{:})
(line 473)
cfun{3} = #(y,varargin)
feval(cfun{3},y,neqgoals,funfcn,confcn,WEIGHT,GOAL,x,errCheck,varargin{:});
Error in nlconst (line 746)
[nctmp,nceqtmp] = feval(confcn{3},x,varargin{:});
Error in fgoalattain (line 519)
[xnew,ATTAINFACTOR,LAMBDA,EXITFLAG,OUTPUT]=...
Error in ppa_model (line 152)
r = fgoalattain(#cirr,0.001,.15,abs(.15))
and using symbolic toolbox doesn't work either.
syms y
solve(irr([-down_pmt ; y*ppam_gen + oth_tot]) == 0.15)
throws the error:
Error using assignin
Attempt to add "y" to a static workspace.
See MATLAB Programming, Restrictions on Assigning to Variables for details.
Error in syms (line 66)
assignin('caller',x,sym(x));
Error in ppa_model (line 152)
syms y