- 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:

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

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I am receiving one of the following error messages. How can I resolve this issue?

Undefined function or variable ‹Name›.

Unrecognized function or variable ‹Name›.

Undefined function or method ‹Name› for input arguments of type ‹ClassName›.

### Accepted Answer

MathWorks Support Team
on 18 Oct 2021

Edited: MathWorks Support Team
on 18 Oct 2021

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) Trying to use a variable that has not been defined before this line of code executes.

>> x=1:10;

>> t=x.^2;

>> plot(x,y)

Undefined function or variable 'y'.

% Possible corrections:

% Change line 3 to "plot(x,t)"

% or change line 2 from "t=x.^2;" to "y=x.^2;"

2) A typographical error when typing a function or variable name. 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

3) The wrong case for a function or variable name. Later versions of MATLAB try to resolve these typos with “Did you mean” suggestions.

4) Changing directories so that a function you used is no longer on the MATLAB path.

5) 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.

6) Calling an object method without an object as the first input.

7) Using a MEX function that is compiled on a platform different from the one in use.

8) Trying to use a function that has been removed from MATLAB. In later versions of MATLAB, this is not an “Undefined function or variable” error, and MATLAB lets you know the new, preferred function to use.

Solution:

>> restoredefaultpath % This will remove any custom paths

>> rehash toolboxcache

>> savepath

##### 11 Comments

Walter Roberson
on 18 Oct 2021

In addition to the Mathworks list:

9) You might be trying to use a variable that has been cleared.

If your code includes

clear all

or

clearvars %without the name of a variable

then you should probably get rid of those statements from your code.

If you had those statements in order to prevent old variables from interfering with new uses, then you should probably be rewriting the code as a function.

### More Answers (47)

Iman Tahamtan
on 25 Mar 2018

I am facing this error when running y_lambda=lambda: Undefined function or variable 'lambda'.

ishwarya ramesh
on 27 Mar 2018

##### 4 Comments

Walter Roberson
on 10 Oct 2021

Liliana Malik
on 6 Apr 2018

##### 5 Comments

Alex Alex
on 10 Apr 2018

##### 1 Comment

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

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
on 12 Apr 2018

What shows up if you use

radios = findall(0, '-property', 'SelectionChangedFcn');

get(radios, 'SelectionChangedFcn')

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.

##### 2 Comments

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

Stephen23
on 23 Jun 2018

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
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'.

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
on 2 Nov 2018

David Akin
on 1 Nov 2018

##### 0 Comments

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

Darrell
on 6 Feb 2019

##### 0 Comments

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)

##### 3 Comments

Walter Roberson
on 24 Jun 2019

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 !

##### 0 Comments

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

##### 0 Comments

Ashwanth Ramesh
on 18 Oct 2019

##### 2 Comments

Sara Alkhaldi
on 29 Jan 2020

##### 1 Comment

Walter Roberson
on 29 Jan 2020

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
on 20 Apr 2020

The proper function name is imaghwinfo . You need to change line 81 of CAMERA_MATLAB.m

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

Alex Backer
on 24 Apr 2020

##### 0 Comments

José Moctezuma Rodríguez Santillán
on 9 May 2020

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

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...

##### 0 Comments

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.

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
on 30 Nov 2020

Your code does not show any function definition for HMMen .

Your code looks like a modified version of https://github.com/ryanrhymes/ehmm/blob/master/%2Bhmm/HMMbaumwelch.m

islam dib
on 3 Dec 2020

Undefined function or variable 'seriallist'.

release 2013b

what's wrong ?

##### 1 Comment

Walter Roberson
on 3 Dec 2020

AMAR Abdelhamid
on 6 Dec 2020

hello

i have this problem :

Error using mphload

Cannot find COMSOL server

how can i sole it, please.

##### 1 Comment

Walter Roberson
on 6 Dec 2020

Have you installed the third-party product COMSOL ?

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
on 21 Jan 2021

Evelin Ponce
on 17 Mar 2021

##### 0 Comments

khallad jobah
on 24 Mar 2021

rigid3d function is not defined

my code : rigid3d(eye(3), [0 0 0])

##### 2 Comments

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.

##### 2 Comments

Feng Chen
on 20 May 2021

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);

##### 1 Comment

Rupam Jaiswal
on 21 Jun 2021

Unrecognized function or variable

'CentroidTermX'.

what can i do?

##### 1 Comment

Walter Roberson
on 21 Jun 2021

[CentroidTermX,CentroidTermY]=find(ZTerm);

according to archives I find of Florence Kussener, The MathWorks % Application Engineer % August 2007

Arnaud Yossa potawe
on 29 Jul 2021

##### 1 Comment

Walter Roberson
on 29 Jul 2021

Sorry, I do not find any references to mbs_bode routine anywhere. Where did you find the code?

MEGHA GUPTA
on 21 Aug 2021

Unrecognized function or variable 'gen_gfdm' how to solve this problem in matlab simulator

##### 1 Comment

Walter Roberson
on 21 Aug 2021

Amy Morris
on 22 Aug 2021

##### 2 Comments

ABHISHEK MAURYA
on 9 Sep 2021

while running vanet in matlab2021a in ubuntu desktop i am getting this error, I don't have any idea why this is happenning. Any valuable suggestion is welcome. Thank you!

Checking app_wsmp2msg_mex...

Checking phy_waveform2psdu_data_mex

phy_waveform2psdu_data_mex not found.

Unrecognized function or variable 'helperSubcarrierIndices'.

Error in phy_channelpacketDetection_data (line 17)

[data,pilots] = helperSubcarrierIndices(cfgnonHT,'HT');

Error in fcn_codeGen (line 28)

[pktOffset,cfgnonHT,outWaveform] = phy_channelpacketDetection_data(inWaveform,SNR,PSDULength);

Error in vanet_init (line 155)

fcn_codeGen

Error in fcn_runModel (line 24)

vanet_init();

Error in vanet>runButton_Callback (line 187)

fcn_runModel(simTime,roadtype,minVehicleNum,maxVehicleNum,gap,simRound,errBar,macTXT,appTXT,mapUI)

Error in gui_mainfcn (line 95)

feval(varargin{:});

Error in vanet (line 42)

gui_mainfcn(gui_State, varargin{:});

Error in matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)vanet('runButton_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating UIControl Callback.

Mariya Ali
on 21 Sep 2021

Hi!

I am getting an error calculating the lyaprosen. The error I get is

"Unrecognized function or variable 'dist'.

Error in lyaprosen (line 106)

Dmm=dist(EEMmm(:,1:k)')"

##### 1 Comment

Gonzalo Cruz Torrijos
on 25 Sep 2021

>>fibonacci(n) Unrecognized function or variable 'n'.

##### 2 Comments

Kevin T
on 3 Nov 2021

Hi!

Here is my code:

[data] = rdsamp('ecgfile');

save ('TEST101.mat', 'data');

My code runs fine but when I convert my code to a executable file (.exe) and open the .exe file, it shows:

'Undefined function 'getWfdbClass' for inputs arguements of type 'char''.

It seems like my .exe file doesn't involve wfdb toolbox.

Any ideas how to solve this? I would be very grateful of any help.

Thank you!

##### 1 Comment

Walter Roberson
on 3 Nov 2021

This appears to refer to the third-party toolbox https://github.com/ikarosilva/wfdb-app-toolbox