MATLAB Answers

Not Enough Input Arguments

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Hi, I'm very new to MATLAB and I am having some trouble. Lots of people have had the same problem but nobody seems to be able to explain or solve it in plain English. Could somebody please explain what this error is and how to fix it?
I have a simple function:
function [r]=Mec134function(w,theta_deg)
t2=10000;
theta_rad=(theta_deg./180).*pi;
t1=55090./(10*sin(theta_rad));
rx=(t1.*cos(theta_rad))-t2;
ry=w-(t1.*sin(theta_rad));
r=((rx).^2+(ry).^2).^0.5;
end
It seems to give this error for line 3 but I'm not sure why.
Thanks.
  9 Comments
Walter Roberson
Walter Roberson on 7 Oct 2019
Line 38 of which function?

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Accepted Answer

Akiva Gordon
Akiva Gordon on 8 Nov 2012
Edited: MathWorks Support Team on 27 Nov 2018
Your function defines 2 input arguments (w and theta_deg). When you run Mec134function, you must specify exactly two inputs, otherwise you will get the error "Not enough input arguments".
For example, if you run the Mec134function in the command window without specifying any arguments:
>> Mec134function
You get this error:
Not enough input arguments.
Error in Mec134function (line 3)
theta_rad=(theta_deg./180).*pi;
If you run the Mec134function and specify two input arguments, "w" and "theta_deg" (assuming "w" and "theta_deg" are defined), you do not get the error message:
>> Mec134function(w,theta_deg)
If you have the file "Mec134function.m" open in the Editor and you try to run the function by pressing the "Run" button or F5, MATLAB runs the Mec134function without any input arguments, and you get the error "Not enough input arguments". The "Run" button dropdown menu then opens prompting you to enter values for the missing input arguments.
Add the desired values and press enter. The values you enter are set as the default inputs when you click the "Run" button or F5 in the future.
To change the values, press the down arrow below the "Run" button and enter new values.
  5 Comments
Evan Curatolo
Evan Curatolo on 27 Sep 2020
Oh man. Bless your soul. Thank you for this comment.

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More Answers (15)

TheLimpNinja
TheLimpNinja on 7 Nov 2012
Edited: Walter Roberson on 15 Jul 2016
sorry the function is
function [r]=Mec134function(w,theta_deg)
t2=10000;
theta_rad=(theta_deg./180).*pi;
t1=55090./(10*sin(theta_rad));
rx=(t1.*cos(theta_rad))-t2;
ry=w-(t1.*sin(theta_rad));
r=((rx).^2+(ry).^2).^0.5;
end
if that's clearer :-)
  3 Comments
Steven Lord
Steven Lord on 27 Dec 2016
Prior to release R2015b the deg2rad and rad2deg functions were part of Mapping Toolbox. In that release they moved into MATLAB.
As another solution that avoids converting between degrees and radians, MATLAB also has functions sind and cosd for computing the sine and cosine of angles in degrees and those have been part of MATLAB for quite some time. [I don't remember exactly when they were introduced.]

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TheLimpNinja
TheLimpNinja on 7 Nov 2012
Edited: Walter Roberson on 7 Nov 2012
Thanks :-)
will have a look at the "getting started"
I have a simple function:
function [r]=Mec134function(w,theta_deg)
t2=10000;
theta_rad=(theta_deg./180).*pi;
t1=55090./(10*sin(theta_rad));
rx=(t1.*cos(theta_rad))-t2;
ry=w-(t1.*sin(theta_rad));
r=((rx).^2+(ry).^2).^0.5;
end
that seems to give this error for line 2 but I'm not sure why.
  2 Comments
Waldemiro Kubucama
Waldemiro Kubucama on 1 Aug 2020
Hello, first press button "Run" in Matlab and after only you press the button "ENTER" i your computer. I think your problem will be solved.

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Brian Batson
Brian Batson on 29 Nov 2012
Edited: Brian Batson on 29 Nov 2012
I too am very new to Matlab, and tried to run the code above in .m (JP Donlon on Nov. 7th). However, I keep getting an error stating "Not enough input arguments." I'm not sure what this means, because I have attempted to run other code by professors which works on other computers. Is it something with my preference settings?
Also, when I run the Code Analyzer, there are no issues...not sure what is going on.
  4 Comments
Walter Roberson
Walter Roberson on 29 Mar 2020
https://www.mathworks.com/matlabcentral/answers/53100-not-enough-input-arguments#comment_109973

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Annie micheal
Annie micheal on 15 Jul 2016
Edited: Walter Roberson on 15 Jul 2016
How to rectify this error
Error using DetectFace (line 68)
Not enough input arguments.
the code is given below
I=imread('lena.jpg');
minFace = 20; % minimal size of the face that you are searching for
maxFace = 4000; % maximal size of the face that you are searching for
overlappingThreshold = 0.5; % overlapping threshold for grouping nearby detections
numThreads = 24; % number of cpu threads for parallel computing
if nargin > 2 && ~isempty(options)
if isfield(options, 'minFace') && ~isempty(options.minFace)
minFace = options.minFace;
end
if isfield(options, 'maxFace') && ~isempty(options.maxFace)
maxFace = options.maxFace;
end
if isfield(options, 'overlappingThreshold') && ~isempty(options.overlappingThreshold)
overlappingThreshold = options.overlappingThreshold;
end
if isfield(options, 'numThreads') && ~isempty(options.numThreads)
numThreads = options.numThreads;
end
end
%%test detector
if ~ismatrix(I)
I = rgb2gray(I);
end
candi_rects = NPDScan(model, I, minFace, maxFace, numThreads);
%%post processing
if isempty(candi_rects)
rects = [];
return;
end
  3 Comments
Walter Roberson
Walter Roberson on 15 Jul 2016
Why did you use nargin and return when you wrote this script ? nargin is defined as being 0 within scripts and return can lead to odd behavior when used within a script .
When I search around, it looks to me as if this code is ripped off from https://github.com/biotrump/NPD/blob/master/NPDFaceDetector/DetectFace.m which is a function not a script . An example of calling that function is given in the comments there:
I = imread('lena.jpg');
load('model.mat');
rects = DetectFace(npdModel, I);
You cannot just remove the function line from a function and assign to one variable and expect it to work.

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REEMA MOHANTY
REEMA MOHANTY on 27 Dec 2016
Edited: Walter Roberson on 26 May 2017
clc; clear; close all;
xo=0.4;
A=[];
b=[];
Aeq=[];
beq=[];
Q=100;
R=1;
N = 50;
U0= zeros(100,1);
% Umin= -1*ones(100,1);
% Umax=1*ones(100,1);
% U = fmincon(@cost1,U0,A,b,Aeq,beq,Umin,Umax,[],[],N);
x=xo; h = 0.1;
xo=[-0.5,0.5];
options = optimoptions(@fmincon,'Algorithm','sqp');
U = fmincon(@cost1,U0,[],[],[],[],[],[],@confuneq,options);
for k =1:N
S1= F(x(k),U(k));
S2=F(x(k)+0.5*h*S1,U(k));
S3=F(x(k)+0.5*h*S2,U(k));
S4=F(x(k)+h*S3,U(k));
x(k+1) = x(k) + (1/6)* (S1+ 2*S2+ 2*S3 + S4)*h;
k = k + 1 ;
end
% plot(x);
plot(U);
grid on
figure(); plot(x)
grid on
I new to matlab.Can anyone help me to fix the iisue here.
Its showing not enough input arguments.

vani shree
vani shree on 3 Mar 2017
Edited: Walter Roberson on 3 Mar 2017
Hello sir,I am newer to matlab. I am getting error in this code like "preprocessing requries more input arugument to run". can you please to run this program. my project topic is recognition and matching fake logos using filters.
function img=preprocessing(I)
[x y o]=size(I);
if o==3
I=rgb2gray(I);
end
I=im2double(I);
%%MEDIAN FILTER
med=medfilt2(I);
figure,imshow(med)
title('MEDIAN FILTERED IMAGE')
[psnr_med,mse_med]=psnr(I,med)
%%AVERAGE FILTER
out7= imfilter(I, fspecial('average'));
figure,imshow(out7)
title('MEAN FILTERED IMAGE')
[psnr_avg,mse_avg]=psnr(I,out7)
%%GAUSSIAN FILTER
gau=imfilter(I,fspecial('gaussian'));
figure,imshow(gau)
title('GAUSSIAN FILTER IMAGE')
[psnr_gau,mse_avg]=psnr(I,gau)
%%WEINER FILTER
psf=fspecial('gaussian',7,10);
image1=imfilter(I,psf,'conv','circular');
var1=(1/256)^2/12;
var2=var(I(:));
wei=deconvwnr(image1,psf,(var1/var2));
figure,imshow(wei);title('WEINER FILTERED IMAGE');
[psnr_wei,mse_wei]=psnr(I,wei)
psnr_all=[psnr_med,psnr_avg,psnr_gau,psnr_wei];
psnr_max=max(psnr_all);
val=find(psnr_all==psnr_max);
if val==1
img=med;
disp('median have high psnr');
elseif val==2
img=out7;
disp('mean have high psnr');
elseif val==3
img=gau;
disp('gaussian have high psnr');
else
img=wei;
disp('weiner have high psnr');
end
  3 Comments
Steven Lord
Steven Lord on 24 Mar 2017
vani shree, you should ask this as a separate question since it's not related to the "not enough input arguments" original question. Show what you've written and ask a specific question about where you're having difficulty and you may receive some guidance.

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Ganesh Petkar
Ganesh Petkar on 18 Apr 2017
I am getting error for below function as "Not enough input arguments. "
delayed_signal = mtapped_delay_fcn(input);

Wendell
Wendell on 26 May 2017
Edited: Walter Roberson on 26 May 2017
Hi I'm trying to run Dr. John Stockie's matlab code but I am getting a "Not enough input argument" error. I'm not very well verse with Matlab, so I would appreciate any help...Thank you. I am pasting the code:
function C = ermak( x, y, z, H, Q, U, Wset, Wdep )
% ERMAK: Compute contaminant concentration (kg/m^3) using the
% Gaussian plume model, modified for a deposition and settling
% velocity. This code handles a single source (located at the
% origin) and multiple receptors.
%
% Input parameters:
%
% x - receptor locations: distance along the wind direction, with
% the source at x=0 (m)
% y - receptor locations: cross-wind direction (m)
% z - receptor locations: vertical height (m)
% H - source height (m)
% Q - contaminant emission rate (kg/s)
% U - wind velocity (m/s)
% Wset - gravitational settling velocity (m/s)
% Wdep - deposition velocity (m/s)
%
% Output:
%
% C - contaminant concentration (kg/m^3)
%
% References: Ermak (1977), Winges (1990/1992).
% First, define the cut-off velocity, below which concentration = 0.
Umin = 0.0;
% Determine the sigma coefficients based on stability class C --
% slightly unstable (3-5 m/s).
ay = 0.34; by = 0.82; az = 0.275; bz = 0.82;
sigmay = ay*abs(x).^by .* (x > 0);
sigmaz = az*abs(x).^bz .* (x > 0);
% Calculate the eddy diffusivity (m^2/s).
Kz = 0.5*az*bz*U*abs(x).^(bz-1) .* (x > 0); % K = 0.5*U*d(sigma^2)/dx
% Calculate the contaminant concentration (kg/m^3) using Ermak's formula.
if U < Umin,
C = 0 * z;
else
Wo = Wdep - 0.5*Wset;
C = Q ./ (2*pi*U*sigmay.*sigmaz) .* exp( -0.5*y.^2./sigmay.^2 ) .* ...
exp( -0.5*Wset*(z-H)./Kz - Wset^2*sigmaz.^2/8./Kz.^2 ) .* ...
( exp( -0.5*(z-H).^2./sigmaz.^2 ) + ...
exp( -0.5*(z+H).^2./sigmaz.^2 ) - sqrt(2*pi)*Wo*sigmaz./Kz .* ...
exp( Wo*(z+H)./Kz + 0.5*Wo^2*sigmaz.^2./Kz.^2 ) .* ...
erfc( Wo*sigmaz/sqrt(2)./Kz + (z+H)./sqrt(2)./sigmaz ) );
ii = find(isnan(C) | isinf(C));
C(ii) = 0; % Set all NaN and inf values to zero.
end
and the error message refers to "sigmay" in line 31
  1 Comment
Walter Roberson
Walter Roberson on 26 May 2017
Please read the previous Answers here.

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aarthy reddy R
aarthy reddy R on 4 Sep 2019
Edited: Walter Roberson on 14 Oct 2019
function test(num1, num2,small,s)
load (small, num1, num2)
s = sum(num1, num2)
end
this the code for this i'm getting these errors
Not enough input arguments.
Error in test (line 3)
load (small, num1, num2)
  4 Comments
Walter Roberson
Walter Roberson on 14 Oct 2019
Note: if you pass in the name of a variable as the fourth parameter, then the function you posted will not set that variable to the result of the sum. If you want to return a value in MATLAB you need to code it on the left side of an "=" in the function line. For example,
function s = test(num1, num2, small)
load (small, num1, num2)
s = sum(num1, num2)
end
This is unlikely to work the way you want it. In order for the load() to work there, small and num1 and num2 would each have to be a character vector or else a scalar string variable, and num1 and num2 would have to be in the same form as valid MATLAB variable names. Those names would have to be found inside the .mat file named by the small variable.
With the form of load() you have used, MATLAB would normally "poof" the variable names into existence. However, when you use end matching a function statement, you make a promise to MATLAB that you will not poof variables into existence, and MATLAB is permitted to give an error or to ignore the magically created variables. Therefore after the load, num1 and num2 are probably going to continue to be the character vectors or string objects, and you would attempt to call sum() passing those in. sum() would give an error if the first parameter, num1 is a string object, but would be okay with num1 being a character vector. There are a limited number of character vectors or scalar string objects that are valid for the second parameter of sum(), namely 'all', 'double', 'native', 'default', 'includenan', or 'omitnan' . It would be surprising if you happened to name your variables any of those...

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Chapat
Chapat on 11 Mar 2020
Edited: Walter Roberson on 11 Mar 2020
Hello. Am new in Matlab and I want to do my assignment with this function refraction_2layers and Matlab is saying error using refraction_2layers (line 18 and 25) Here is the whole program
function refraction_2layers(v1, v2, z, FIRST_ARRIVALS_ONLY);
% refraction_2layers(v1, v2, z);
%
% Creates travel time plots for a two-layers system with layer velocities
% v1 and v2 and layer 1 thickness of z
% The FIRST_ARRIVALS_ONLY FLAG may be set to 1 to plot only the first arrivals. By
% default, all arrivals are plotted.
if nargin < 4 FIRST_ARRIVALS_ONLY = 0; end
%% X-positions for geophones (m, relative to source)
x = [0:5:300];
%% Direct wave %% Travels along ground surface (at velocity v1)
t1 = x./v1;
%% Head wave
%% Refracts along z1-z2 boundary
%% Travel time depends on velocities of both layers
%% and thickness of layer 1 only (thickness of layer 2 irrelevant)
t2 = (2*z*sqrt(v2^2-v1^2)/(v1*v2))+x./v2; %% Note slope should be 1/v2!
xcrit = 2*z*v1/(sqrt(v2^2-v1^2));
if isreal(xcrit)
a = min(find(x>xcrit));
end
crossover = ((2*z*sqrt(v2^2-v1^2))/(v1*v2))/(1/v1-1/v2);
b = max(find(x<= crossover));
if FIRST_ARRIVALS_ONLY
plot(x(1:b),t1(1:b)*1000, '.--')
hold on
if isreal(t2)
plot(x(b:end), t2(b:end)*1000, 'r.--')
end
else
plot(x,t1*1000, '.--')
hold on
if isreal(t2)
plot(x(a:end), t2(a:end)*1000, 'r.--')
end
end
xlabel('GEOPHONE OFFSET (m)')
ylabel('TIME (ms)')
grid on
legend('DIRECT WAVE', 'HEAD WAVE')
title(['z1 = ', num2str(z), ' m; v1 = ', num2str(v1), ' m/s; v2 = ', num2str(v2), ' m/s'])
axis ([0 300 0 300])
hold off
  1 Comment
Walter Roberson
Walter Roberson on 11 Mar 2020
I formatted your code for you to make it readable to other people, but I suspect that I did not exactly preserve the line boundaries, so we do not know which lines are giving you the problem. Please mark them by using comments. Please also give the exact error messages.
Also please check the position of the end statements. It looked to me as if you might have had two extra end statements.

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Josilyn Dostal
Josilyn Dostal on 23 Apr 2020
I am really struggling to figure out this "not enough input arguments" error in my code. Any help would be greatly appreciated! This is for a batch distillation problem, and the error is referring to the temp function near the bottom. The code and error are below:
P = 912; % mmHg or 1.2 atm
L0 = 100; % Moles liquid in the still initially
A = [6.90565 6.95464]; B=[1211.033 1344.8]; C=[220.79 219.482]; % Antoine Constants
% x0 = [0.60 0.40]; % Initial liquid concentration xb = 60% xt = 40%
% xf = [0.20 0.80]; % Final liquid concentration xb = 20% xt = 80%
xtspan = linspace(0.40,0.80,100);
[xt, L] = ode45(@Moles, xtspan, L0);
L = L(end);
fprintf('The amount of liquid remaining in the still when liquid mole fraction of toluene reaches 0.80 is %f moles', L);
% Vapor liquid equilibrium ratio, K
function Kt = EquilibriumRatio(Psatt)
Kt = Psatt/P;
end
% Toluene vapor pressure
function Psatt = VaporPressuret(T,A,B,C)
Psatt = 10^(A(2)-B(2)/(T+C(2)));
end
% Benzene vapor pressure
function Psatb = VaporPressureb(T,A,B,C)
Psatb = 10^(A(1)-B(1)/(T+C(1)));
end
% ODE
function dLdx = Moles(xt,L)
T0 = 95.585;
%options = odeset('RelTol',1e-6,'AbsTol',1e-8);
%options = optimset('PlotFcns',{@optimplotx,@optimplotfval});
%options = optimset('Display','iter'); % show iterations
options = optimset('Display','off','TolX',1e-6); % Options
T = fzero(@temp, T0, options);
Psatt = VaporPressuret(T);
Kt = EquilibriumRatio(Psatt);
dLdx = L/(xt*(Kt-1));
end
function Tempfun = temp(T,xt,P,A,B,C)
Psatt = VaporPressuret(T,A,B,C);
Psatb = VaporPressureb(T,A,B,C);
Tempfun = Psatt*xt + Psatb*(1-xt) - P;
end
>> project2
Error using fzero (line 306)
FZERO cannot continue because user-supplied function_handle ==> temp failed with the error below.
Not enough input arguments.
Error in project2>Moles (line 30)
T = fzero(@temp, T0, options);
Error in odearguments (line 90)
f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode45 (line 115)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in project2 (line 7)
[xt, L] = ode45(@Moles, xtspan, L0);
  5 Comments
Josilyn Dostal
Josilyn Dostal on 24 Apr 2020
You are my savior. Youre so nice.

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Maria hassan
Maria hassan on 13 Jul 2020
Hi,
I am getting error 'Not enough input arguments.' I am trying online trail oversion. When I click run icon, it does not allow me to enter the value for the input as there is no option for entering the values. Any advice here please?
Best
Sarah

Gurwinder pal singh Bhinder
hi
I am new to matlab. i am getting error message "extract_features" requires more input arguments to run.
anderror in command window :
>> Extract_Features
Not enough input arguments.
Error in Extract_Features (line 2)
img1 = imread(filename);
code is written below:
function Extract_Features(filename,flag)
img1 = imread(filename);
if ndims(img1) == 3; img1 = rgb2gray(img1); end % Color Images
disp(['Extracting features from ' filename ' ...']);
fir=ext_finger(img1,0);
fir=fir(fir(:,3)<5,:);
if flag ==1
figure;
imshow(img1);
hold on
fir1=find(fir(:,3)==1);
fir3=find(fir(:,3)==3);
plot(fir(fir1,1),fir(fir1,2),'r+');
plot(fir(fir3,1),fir(fir3,2),'bo');
end
filename2=filename; filename2(end-1)='x'; filename2(end)='t';
save(filename2,'fir','-ascii');
end
  8 Comments

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Muhammad Hadyan Utoro
Muhammad Hadyan Utoro on 17 Jun 2021
Can someone help me please
%% Full-wave Rectification and RMS Envelope
rec_EMG = abs(EMG);
envelope = zeros(L,1);
window = 50;
envelope = sqrt(movmean(rec_EMG.^2), 'window');
I was trying to do get the RMS but it says:
Error using movmean Not enough input arguments.
I didn't understand that, as I already use two arguments there.
Thanks fo ryour help
  2 Comments
Muhammad Hadyan Utoro
Muhammad Hadyan Utoro on 17 Jun 2021
Thank you very much Mr. Robertson for the explanation. I put the bracket in the wrong position.
Appreciate your help

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kumar maruthi srinivas chennu
kumar maruthi srinivas chennu on 3 Sep 2021 at 11:28
Edited: kumar maruthi srinivas chennu on 3 Sep 2021 at 12:32
Can any one help me this please
function u = Anti_Tv(g,my,gamma)
gHS = uint8(imadjust (g));
gGC = uint8(255.*((double(g)./255).^(gamma)));
g = double(g(:));
n = length(g);
b = zeros(2*n,1);
d = b;
u = g;
eer = 1;k = 1;
tol = 1e-3;
Lambda = 0.05
[B, Bt, BtB] = DiffOper(sqrt(n));
Not enough input arguments
  2 Comments
kumar maruthi srinivas chennu
kumar maruthi srinivas chennu on 3 Sep 2021 at 12:34
Can you check this and let me know

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