MATLAB Answers

Why do I get the error "Undefined function or variable"?

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I am receiving the following error message, how can I resolve this issue?
ERROR: ??? Undefined function or variable ‹FunctionName›
??? Undefined function or method ‹FunctionName› for input arguments of type ‹ClassName›.

Accepted Answer

MathWorks Support Team
MathWorks Support Team about 13 hours ago
Edited: MathWorks Support Team 5 minutes ago
MATLAB does not recognize the specified string as the name of a function on the MATLAB path or as a variable. "Undefined function or variable" can be caused by:
1) A typographical error when typing a function or variable name (such as typing a 1 [one] when you intended to type an l [low-case L]). However, later versions of MATLAB try to resolve these typos with “Did you mean” suggestions. For example,
foo = 42; fo0 Undefined function or variable 'fo0'. Did you mean: >> foo
2) The wrong case for a function or variable name. Later versions of MATLAB try to resolve these typos with “Did you mean” suggestions.
3) Changing directories so that a function you used is no longer on the MATLAB path.
4) Trying to use a function for which you are not licensed or that belongs to a toolbox that isn’t installed. In later versions of MATLAB, this is not an “Undefined function or variable” error, and MATLAB lets you know that you are either not licensed to use the function or the appropriate toolbox is not installed.
5) Calling an object method without an object as the first input.
6) Using a MEX function that is compiled on a platform different from the one in use.
Solution:
Verify that the undefined function or variable is visible (it is on the path or in the current workspace) and that it has been defined before this line of code executes.
If you are certain the variable or function exists, verify the case of the function or variable name. If the undefined identifier is a function, the 'which' function can help you verify that it is visible to the function where the error occurs.
If you are having problems with your MATLAB search path, run the following MATLAB commands and then restart MATLAB.
restoredefaultpath % This will remove any custom paths rehash toolboxcache savepath
Example demonstrating this error:
UndefinedFunctionOrVariable.m (attached)
  8 Comments
Monika Biela
Monika Biela on 27 Feb 2021
restoredefaultpath % This will remove any custom paths
rehash toolboxcache
savepath
These worked for me- also :)

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More Answers (33)

Iman Tahamtan
Iman Tahamtan on 25 Mar 2018
I am facing this error when running y_lambda=lambda: Undefined function or variable 'lambda'.
  1 Comment
Walter Roberson
Walter Roberson on 26 Mar 2018
Where do you expect that your program should be getting a value of lambda from?

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ishwarya ramesh
ishwarya ramesh on 27 Mar 2018
Undefined function or variable 'drivingScenario'. why do i get this error i just need a clear explanation
  2 Comments
Walter Roberson
Walter Roberson on 27 Mar 2018
That function is part of the Automated Driving System Toolbox, which was new as of R2017b. You probably do not have that installed or licensed. If I recall correctly it is not available for Student licences.

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Liliana Malik
Liliana Malik on 6 Apr 2018
why do i get Undefined function or variable 'pixelLabelDatastore' and Undefined function or variable 'batchNormalizationLayer'
  5 Comments

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Alex Alex
Alex Alex on 10 Apr 2018
Undefined function or variable 'shaperead'. On the description page for this function it says "Introduced before R2006a". I use MATLAB R2015b- academic use. Does that mean that the function is not available for student license? How can I perform this kind of check in the future? Many thanks, Alex.
  1 Comment
Florian Morsch
Florian Morsch on 11 Apr 2018
Type "ver" into the Matlab Command Window. shaperead is part of the Mapping Toolbox, if you dont own it you cant use the function. Normaly it should be included in the academic license, so check if you have downloaded it. If not you may try to load it.
If its not for free in your version you may try to contact your IT so it can be included into the license.
Otherwise, if you have newly created the code try to restart matlab once, sometimes that helps, too.
Best regards

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tim jelly
tim jelly on 12 Apr 2018
When trying to make a GUI i get the error:
Undefined function or variable 'radioChanged'
Error while evaluating ButtonGroup SelectionChangedFcn.
I dont have "radioChanged" in my code so how do I fix this, thanks
  1 Comment
Walter Roberson
Walter Roberson on 12 Apr 2018
What shows up if you use
radios = findall(0, '-property', 'SelectionChangedFcn');
get(radios, 'SelectionChangedFcn')

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Saadia Talay
Saadia Talay on 21 May 2018
Edited: Walter Roberson on 31 May 2020
Undefined function or variable 'lgemri' when I enter the following:
[X,meta]=nrrdread(lgemri);
The nrrdread function has been taken from the matlab file exchange: https://www.mathworks.com/matlabcentral/fileexchange/34653-nrrd-format-file-reader
The lgemri is a file in nrrd format.

Francisco Santamaría
Francisco Santamaría on 23 Jun 2018
Edited: Francisco Santamaría on 23 Jun 2018
for i=1:(npop+1)
dron(i,:)=rand(1,nvar).*(xmax-xmin)+xmin;
cost(i)=CostfunctA3(dron(i,:));
dron_cost(i,:)=[dron(i,:) cost(i)]
end
When trying to make a run i get the following error:
Undefined function or variable 'CostfunctA3'.
  1 Comment
Stephen Cobeldick
Stephen Cobeldick on 23 Jun 2018
@Francisco Santamaría: have you defined/downloaded a function named CostfunctA3? Is it on the MATLAB path?

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Waqas Waqas Ul Hussan
Waqas Waqas Ul Hussan on 23 Aug 2018
Edited: Walter Roberson on 24 Aug 2018
hi
I am getting this problem in Matlab when plotting the graphs with shaded area.
Undefined function or variable 'jbfill'.
These below are my code lines. error is in line 127 below.
  7 Comments
yousra aichoun
yousra aichoun on 6 May 2020
hi ,
can you help me please i'm having the same problem but with simulink ,once i run the simulation , it display :Undefined function 'modelRegistry' for input arguments of type 'PmSli.RunTimeModule'.

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David Akin
David Akin on 1 Nov 2018
Edited: David Akin on 2 Nov 2018
Same error but using a Mathworks example. Here's the contents of fact.m
function f = fact(n)
f = prod(1:n);
end
Located here:
/opt/software/MATLAB/2018a/toolbox/local/fact.m
When trying to use:
>> y=fact(5);
Undefined function or variable 'fact'.
I cd'ed to the directory containing the file before starting MATLAB and it's in the search path:
>> path
MATLABPATH
/opt/software/MATLAB/2018a/toolbox/local
.
.
.
Any suggestions?
>> dos('cat /opt/software/MATLAB/2018a/toolbox/local/fact.m');
function f = fact(n)
f = prod(1:n);
end
  4 Comments
Steven Lord
Steven Lord on 2 Nov 2018
Do not store your own files in a directory under the matlabroot directory. See this documentation page for some of the reasons why. If you must do so, that documentation page will also tell you how you can.
Consider storing your files in your userpath folder instead.

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David Akin
David Akin on 1 Nov 2018
It's an example only, as I've got some code from a colleage (a collection of .m files) I'd like to use. However it's not finding the functions. Thank you though.

michael
michael on 14 Nov 2018
(Matlab R14)
Something strange is that when I try to call some function from toolbox (communication) I'm getting that it is not existing.
Even when I'm going to %MATLABROOT%\toolbox\comm\comm where the m file is existing, I still can't run it.
Please suggest what is the issue
  2 Comments
Hector Diaz
Hector Diaz on 27 Mar 2020
Thanks for the advice!!, it works perfectly to solve the problem!!

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Darrell
Darrell on 6 Feb 2019
I have seen this issue before with other functions. As stated before, first check that the function name is spelled correctly and that the function is located in the matlab search path. Assuming those two things check, then delete the path where the function is located, then reset the path. I would also will restart Matlab. I'm not sure why, but this seems to correct the problem.

Al3jandro
Al3jandro on 24 Jun 2019
Hi.
I'm making this rutine, but i cant get values of K, how can I resolve this issue?
clear;
clc;
A=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','B1:B6');
I=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','C1:C6');
E=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','D1:D6');
W=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','u1:u6');
L=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','Q1:Q6');
a=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','R1:R6');
n=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','V3');
nGDL=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','NUDOS','J2');
GDLG=xlsread('ANÁLISIS DE ESTRUCTURAS _ INPUT2','BARRAS','K2:P4');
for i=1:n
A=A(i);
I=I(i);
E=E(i);
L=L(i);
a=a(i);
KL(i)=[E*A/L 0 0 -E*A/L 0 0;0 12*E*I/L^3 6*E*I/L^2 0 -12*E*I/L^3 6*E*I/L^2;0 6*E*I/L^2 4*E*I/L 0 -6*E*I/L^2 2*E*I/L;-E*A/L 0 0 E*A/L 0 0;0 -12*E*I/L^3 -6*E*I/L^2 0 12*E*I/L^3 -6*E*I/L^2;0 6*E*I/L^2 2*E*I/L 0 -6*E*I/L^2 4*E*I/L];
T(i)=[cos(a) sin(a) 0 0 0 0;-sin(a) cos(a) 0 0 0 0;0 0 1 0 0 0;0 0 0 cos(a) sin(a) 0;0 0 0 -sin(a) cos(a) 0;0 0 0 0 0 1];
KG(i)=T(i)'*KL(i)*T(i);
G=[GDLG(i,1) GDLG(i,2) GDLG(i,3) GDLG(i,4) GDLG(i,5) GDLG(i,6)];
KT=zeros(nGDL,nGDL);
KT(G,G)=KG(i);
if i==1
K=zeros(nGDL,nGDL);
end
K=K+KT;
end
disp(K)

clpi
clpi on 3 Jul 2019
Hello !
I have a matlab function which at a certain point calculates sin(2*pi*freq*t_array) (t_array in an array of size (1,2000).
I tried to call this function via matlab.engine but I got the error message: "Undefined function 'sin' for input argument of type 'int64' "
I wanted to add the file 'sin.m' to my working directory but it is not a function script, it is a simple text.
I would be very grateful of any help
Thank you !

Regina Vivian Barli
Regina Vivian Barli on 8 Jul 2019
Hello, I happen to stumble upon similar problem.
So I have been trying to use matlab for video stabilising, but keep getting this error:
Undefined function or variable 'cvexEstStabilizationTform'.
even though I have followed Matlab's instruction by running a command by clicking
edit cvexEstStabilizationTform.m
Can anyone please suggest me what to do?
Kind regards
Vivian

Ashwanth Ramesh
Ashwanth Ramesh on 18 Oct 2019
I am trying to upload audio data into matlab using audioDatastore funtion and the same error pops up. Please help!
Screenshot (102).png

Sara Alkhaldi
Sara Alkhaldi on 29 Jan 2020
The functions stepseq, impseq, and nextpow2 do not work in the MATLAB R2018B and I don't know why. Can someone please help?
Screen Shot 2020-01-29 at 4.15.16 PM.png
  1 Comment
Walter Roberson
Walter Roberson on 29 Jan 2020
nextpow2 should be part of MATLAB but the other two are from a book https://www.mathworks.com/matlabcentral/fileexchange/2189-digital-signal-processing-using-matlab

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abood qamar
abood qamar on 1 Apr 2020
can please help me to solve this problem
  2 Comments
Walter Roberson
Walter Roberson on 1 Apr 2020
Is this related to MIMO-OFDM Wireless Communication with Matlab book?

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apri zulham
apri zulham on 19 Apr 2020
i need help!!
Undefined function or variable 'imaghwinfo'.
Error in CAMERA_MATLAB>pushbutton1_Callback (line 81)
IAHI = imaghwinfo;
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in CAMERA_MATLAB (line 42)
gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)CAMERA_MATLAB('pushbutton1_Callback',hObject,eventdata,guidata(hObject))
81 IAHI = imaghwinfo;
  1 Comment
Walter Roberson
Walter Roberson on 20 Apr 2020
The proper function name is imaghwinfo . You need to change line 81 of CAMERA_MATLAB.m

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CS
CS on 20 Apr 2020
Undefined function or variable 'readmatrix'.
I have a basic_matrix.txt file including
6,8,3,1
5,4,7,3
1,6,7,10
4,2,8,2
2,7,5,9
I want to read the contents of this file (basic_matrix.txt). When I write
M = readmatrix('basic_matrix.txt')
MATLAB gives an error as
Undefined function or variable 'readmatrix'.
M = readmatrix('basic_matrix.txt')
Does anyone know what the reason is?
I am just trying to implement what is written on https://www.mathworks.com/help/matlab/ref/readmatrix.html in order to read the contents of a file. I am using MATLAB R2018b.
Any help would be appreciated.
  2 Comments
Walter Roberson
Walter Roberson on 20 Apr 2020
Or really for that file you could just load() the file.

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Alex Backer
Alex Backer on 24 Apr 2020
This happened to me with mean and median when I indvertently called it mean(variable,:) instead of mean(variable,1).

José Moctezuma Rodríguez Santillán
Edited: Walter Roberson on 9 May 2020
Undefined function or variable 'isfile'. You cannot find the isfile function in MATLAB R2015. any alternative to replace? this is my code;
options = weboptions('Username', 'insertusername', 'Password', 'insertpassword');
year = 2016;
month = 03;
time = 0900;
start_jd = 011;
end_jd = 045;
for jd = start_jd:end_jd
cd = day(datetime((year-1),12,31) + days(jd));
filename = ['SST' num2str(year) '_' num2str(jd) '.nc'];
if isfile(filename)
fprintf('already have the file |%s|\n',filename);
else
url=['https://data.nodc.noaa.gov/ghrsst/L4/GLOB/JPL_OUROCEAN/G1SST/2016/' num2str(year) '/' num2str(jd)];
outname=websave(filename,url,options);
fprintf('got weather data file |%s|\n',outname);
end
end
  1 Comment
Walter Roberson
Walter Roberson on 9 May 2020
Change
if isfile(filename)
to
if exist(filename, 'file')

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Yinying Wang
Yinying Wang on 16 May 2020
Help!
I received "undefined function 'string2char' for 'char' type input arguments".
This error occurs only when I use mphload('filename') in an exe file. When in a .m file this line works well. I thought maybe mphload use 'string2char' function whatever its input argument type is. I use mphload("filename") instead. It still doesn't work...

Joey Porter
Joey Porter on 7 Jul 2020
Hi all,
I've had this error after a newly created function would give this error even though it was in the correct path and was user-defined (so no problem with needing the correct toolbox or licencing).
The name of the function and the file name you save it as MUST BE THE SAME.
I had saved my function a different name and therefore gave this error. This tip isn't in the accepted answer's response so give this a try.
  6 Comments

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soufiane kabiri
soufiane kabiri on 18 Sep 2020
Edited: Walter Roberson on 30 Nov 2020
hi everyone, i hope you'll help me with that
i have the same error "Undefined function or variable 'HMMem'"
this the code:
function [Q, g, l] = HMMbaumwelch(y, nu, tol, maxIt, Q, g)
% HMMbaumwelch compute maximum likehood estimate using Expectation-Maximization
% iterations
%
% in : y = vector of observations
% nu = initial distribution of the hidden chain
% tol = tolerance for the stopping criterion
% maxIt = maximal number of iterations
% out : Q = estimate of the transition matrix of the hidden markov process
% g = estimated probabilities of transition: gh(x,y) = estimate of P(Y=y | X=x) for 1<=x<=k
% l = log-likelihood of y for parameters Q and g
%
% Example :
n = 10000;
nu = [0, 1];
Q = [0.8, 0.2; 0.1, 0.9];
g = [0.25 0.25 0.25 0.25; 0.05 0.05 0.45 0.45];
[x,y] = HMMsample(nu, Q, g, n);
[Qh, gh] = HMMem(y, nu);
% % compare estimates with truth: note that the order of the hidden
% % states may not be preserved
Q, Qh
g, gh
% References: Hidden Markov Models by Cappe, Moulines, Rydden
% Springer series in statistics
% by Aurelien Garivier, CNRS & Telecom ParisTech
% last revision February 7, 2012
global myfilter mysmoother % should be either HMMfilter/HMMsmoother, or HMMfilter_C/HMMsmoother_C
if nargin<4, maxIt = 100; end
if nargin<3, tol = 1e-4; end
k = length(nu); r = max(y); n = length(y);
Y = zeros(n, r); Y(sub2ind([n, r], 1:n, y))=1;
% if they are not provided, sample random initial transition and emission matrices
if nargin<5, Q = rand(k); Q = Q ./ (sum(Q, 2)*ones(1, k)); end
if nargin<6, g = rand(k, r); g = g ./ (sum(g, 2)*ones(1, r)); end
it = 0; oldQ = Q; oldg = g+tol+1;
while ((norm(oldQ(:)-Q(:), 1) + norm(oldg-g, 1) > tol) && (it<maxIt))
it = it + 1;
% compute the posterior distribution for the current parameters
[phi, c] = myfilter(y, nu, Q, g);
beta = mysmoother(y, Q, g, c);
post = phi .* beta;
% expectation of the number of transitions under the current parameters
N =Q.*(phi(:, 1:(end-1))*(beta(:, 2:end).*g(:, y(2:end))./(ones(k, 1)*c(2:end)))');
% expectation of the number of emissions
M = post * Y;
% re-estimation
oldQ = Q; oldg = g;
Q = N ./ (sum(N, 2) * ones(1, k));
g = M ./ (sum(M, 2) * ones(1, r));
end
l = sum(log(c));
  1 Comment
Walter Roberson
Walter Roberson on 30 Nov 2020
Your code does not show any function definition for HMMen .

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Nicole Yousef
Nicole Yousef on 29 Nov 2020
I'm having the same issue for trying to read a Java file (TimeSeriesTableVec3) from a MATLAB function:
Unrecognized function or variable 'TimeSeriesTableVec3'.
TimeSeriesTableVec3 is a Java file that is present in the same folder.
(Additional information: resetting the default path caused MATLAB to try to create a .m file out of the Java file, which then fails to run.)
  4 Comments
Nicole Yousef
Nicole Yousef on 1 Dec 2020
I have gotten this code to work without compiling it once before on a Macbook just like this, so it is unlikely that it is necessary to compile it. I tried compiling it using an online compiler and with my Mac's terminal. So far have run into 57 errors both times converting it online and in my Mac's terminal. The errors look like this:
error: cannot find symbol
public class TimeSeriesTableVec3 extends DataTableVec3 {
^
symbol: class DataTableVec3
TimeSeriesTableVec3.java:48: error: cannot find symbol
public TimeSeriesTableVec3(StdVectorDouble indVec, MatrixVec3 depData, StdVectorString labels) {
^
symbol: class StdVectorDouble
location: class TimeSeriesTableVec3
TimeSeriesTableVec3.java:48: error: cannot find symbol
public TimeSeriesTableVec3(StdVectorDouble indVec, MatrixVec3 depData, StdVectorString labels) {
^
symbol: class MatrixVec3
location: class TimeSeriesTableVec3
TimeSeriesTableVec3.java:48: error: cannot find symbol
public TimeSeriesTableVec3(StdVectorDouble indVec, MatrixVec3 depData, StdVectorString labels) {
^
... and so on, where every class they point out is listed in the next symbol.
I think it might require having the "package org.opensim.modeling;" available in the same space or text box where I am trying to compile the Java file?
(Also thank you so much for your help!)

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islam dib
islam dib on 3 Dec 2020
Undefined function or variable 'seriallist'.
release 2013b
what's wrong ?
  1 Comment
Walter Roberson
Walter Roberson on 3 Dec 2020
serialport objects are a much newer release than what you have. You need to use serial() objects and https://www.mathworks.com/help/matlab/ref/instrfind.html

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Eamon Devlin
Eamon Devlin on 21 Jan 2021
I have a probelm:
I have a list of varibles defined at the top of my script but when I am trying to create a function the defined variables (which are in the workspace too) are not being recognised.
%% Damped Oscillating Spring System
m_c = 2; %Container mass in kg
s1 = 16.0; % Spring constant, spring 1, N/m
s2 = 16.0; % Spring constant, spring 2, N/m
c = 2.0; % Damping Coefficient, Ns/m
d = 0.6; % Initial gap between mass and spring 2, m
t_total = 20.0; % Total interation time, s
dt = 0.01; % Interation Step, s
x =1; % Initial displacement, m
g = -9.81; % Gravitational Acceleration, m/s^-2
t = 0: dt: t_total; % Total Time for plotting graphs
r_m = 0.1; % Rate of mass of fluid change in kg/s
m_f_max = 4; % Maximum Fluid mass
%Then there is a choice menu and other calculations where the cases are all set out:
case {4} %Select if the containter is filled with fluid duing the simulation
[r_m] = fluidcalcs();
function [r_m] = fluidcalcs()
r_m = input('Rate of Change of Fluid Mass (kg/s)?\n\n');
if (r_m * t_total) > 4
disp('Invalid Entry - Maximum Fluid Mass is 4kg\n\n');
r_m = input('Rate of Change of Fluid Mass (kg/s)?\n\n');
end
end
In this case the 't_total' variable is not being recognised. The code works fine if I replace the variable name with the value. But the varables need to be changed each time so having a set value isn't what I want.
Any solutions?
  1 Comment
Walter Roberson
Walter Roberson on 21 Jan 2021
That structure is not valid. case is only valid inside switch() but you cannot define a function inside of switch.

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Evelin Ponce
Evelin Ponce on 17 Mar 2021
Maybe you should try to look for the function on the 'Add Ons' section so you could find the package which contains the function you need. All you have to do is to install the package.

khallad jobah
khallad jobah on 24 Mar 2021
rigid3d function is not defined
my code : rigid3d(eye(3), [0 0 0])
  2 Comments
khallad jobah
khallad jobah on 25 Mar 2021
Thanks, I figured that I have to update my Matlab ( it was 2019)

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JITHIN P M
JITHIN P M on 26 Mar 2021
While running a mathlab code for Beamforming am getting the error as mentiond below,
" Unrecognized function or variable 'm_proj' "
Anyone who knows abouth this please help me to solve the issue. Due to this error my whole work is pending. Kindly please help me out.

Feng Chen
Feng Chen on 20 May 2021 at 13:58
Hi, I get the following error. Looking for solutions
Unrecognized function or variable 'xVOCap'.
Error in YTOwrapper (line 53)
res(ii).ap_auc = xVOCap(res(ii).rec, res(ii).prec);

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