I am getting error in the line load SPR_data.txt after intializing n_Au

SPR_matrix_profile_comparison_v2()

Warning: Ignoring extra legend entries.

Error using load
Unable to find file or directory 'SPR_data.txt'.

Error in solution>SPR_matrix_profile_comparison_v2 (line 51)
load SPR_data.txt ;

function SPR_matrix_profile_comparison_v2
%variables
n_Ma=1.493; %målt ved 589nm @ 20 C
n_buffer=1.33156; %HEPES buffer
d_Ma=1E-9;
%vinkelting
theta_start=49.01; %GRADER! !
theta_slut=54.99; %GRADER! !
thetasteps=250;
theta_start=theta_start/360*2*pi ;
theta_slut=theta_slut/360*2*pi ;
deltatheta=(theta_slut-theta_start)/(thetasteps-1);
for t =1:1:thetasteps;
    theta=theta_start+deltatheta*(t-1);
    vinkel(t)=theta/(2* pi)*360 ;
end
figure(1) ;
hold on
for l =2:8
    d_Au=l*10E-9;
    [R_list]=spr_calc(n_Ma,n_buffer,d_Ma,d_Au,vinkel,theta_start,theta_slut,deltatheta,thetasteps,theta); 
    % [y_data]=data_import(vinkel);
    if l==2
        plot( vinkel , R_list ,' k ')
    end
    if l==3
        plot ( vinkel , R_list ,' g ')
    end
    if l==4
        plot ( vinkel , R_list ,'m')
    end
    if l==5
        plot ( vinkel , R_list ,'c')
    end
    if l==6
        plot ( vinkel , R_list ,' b ')
    end
    if l==7
        plot ( vinkel , R_list , ' y ' )
    end
    if l==8
        plot ( vinkel , R_list , ' r ' )
    end
end
%axis ( [ theta_start *180/ pi theta_slut *180/ pi+1e-3 0 1 ] )
legend ( '20nm' , ' 30nm' , ' 40nm' , ' 50nm' , ' 60nm' , ' 70nm' , ' 80nm' , ' Location ' , ' NorthEastOutside ' )
%l egend ( 'n_3=1.3300 ' , 'n_3=1.3340 ' , 'n_3=1.3380 ' , 'n_3=1.3420 ' , 'n_3=1.3460 ' , 'n_3=1.3500 ' , ' Locatxlabel ( ' Angle o f incidence ' )
ylabel ( ' Reflectance ' );
load SPR_data.txt ;
[ sx , sy ]= size (SPR_data) ;
for i =1:250
    y_data ( i )=SPR_data( i +150 ,2)/7E4 ;
    %x_data ( i )=i ;
end
% options = fitoptions ( ' NonlinearLeastSquares ' ,method ) ;
%
%
% [ fresult , gof , fout ]= fit (vinkel, y_data , spr_calc , options ) ;
%figure(1) ;
%hold on
%plot( vinkel , R_list )
%hold on ;
%figure ( 1 ) ;
%plot(vinkel , R_list )
%figure (2) ;
%plot(vinkel , y_data ) ;
%figure(2) ;
%plot(vinkel , R_list-y_data ) ;
end
function  [R_list] = spr_calc(n_Ma,n_buffer,d_Ma,d_Au,vinkel,theta_start,theta_slut,deltatheta,thetasteps,theta)
lambda_0=780E-9;
n_glass =1.77;
n_Au=0.17-4.93i;
n_Cr=3.11982+3.44408i ; % http : / / refractive index . info/? group=METALS&material=Chromium d.11n_Au=0.17-4.93i ; %Stenberg etal . 1991
n_Ma=n_Ma;
n_buffer=n_buffer ;
d_Cr=1E-9;
d_Au=d_Au;
d_Ma=d_Ma;
% theta_start=51; %GRADER! !
% theta_slut=55; %GRADER! !
% thetasteps=250;
n1=n_glass ;
n2=n_Cr ;
n3=n_Au;
n4=n_Ma;
n5=n_buffer;
eps1=n1^2;
eps2=n2^2;
eps3=n3^2;
eps4=n4^2;
eps5=n5^2;
k=2*pi/lambda_0 ;
% theta_start=theta_start /360*2* pi ;
% theta_slut=the ta_slut /360*2* pi ;
% deltatheta=( theta_slut-theta_start ) / (thetasteps-1);
for t =1:1: thetasteps
    theta=theta_start+deltatheta *( t-1);
    kx=k* n_glass * sin ( theta ) ;
    kz1=sqrt (-(kx^2)+k^2* eps1 ) ;
    if imag ( kz1 )>0 ,
        kz1=-kz1 ;
    end
    kz2=sqrt (-(kx^2)+k^2* eps2 ) ;
    if imag ( kz2 )>0 ,
        kz2=-kz2 ;
    end
    kz3=sqrt (-(kx^2)+k^2* eps3 ) ;
    if imag ( kz3 )>0 ,
        kz3=-kz3 ;
    end
    kz4=sqrt (-(kx^2)+k^2* eps4 ) ;
    if imag ( kz4 )>0 ,
        kz4=-kz4 ;
    end
    kz5=sqrt (-(kx^2)+k^2* eps5 ) ;
    if imag ( kz5 )>0 ,
        kz5=-kz5 ;
    end
    beta_Cr=kz2*d_Cr ; %2*pi /lambda_0 *(n_Cr*d_Cr* cos ( theta ) ) ;
    beta_Au=kz3*d_Au; %2*pi /lambda_0 *(n_Au*d_Au* cos ( theta ) ) ;
    beta_Ma=kz4*d_Ma; %2*pi /lambda_0 *(n_Ma*d_Ma* cos ( theta ) ) ;
    L_Cr=zeros(2) ;
    L_Cr(1 ,1)=exp(-1i *beta_Cr ) ;
    L_Cr(2 ,2)=exp (1i *beta_Cr ) ;
    L_Au=zeros(2) ;
    L_Au(1 ,1)=exp(-1i *beta_Au ) ;
    L_Au(2 ,2)=exp (1i *beta_Au ) ;
    L_Ma=zeros(2) ;
    L_Ma(1 ,1)=exp(-1i *beta_Ma ) ;
    L_Ma(2 ,2)=exp (1i *beta_Ma ) ;
    b1=(n1/n2 )^2*( kz2 /kz1 ) ;
    b2=(n2/n3 )^2*( kz3 /kz2 ) ;
    b3=(n3/n4 )^2*( kz4 /kz3 ) ;
    b4=(n4/n5 )^2*( kz5 /kz4 ) ;
    rho_glass_Cr=(1-b1)/(1+b1 ) ;
    rho_Cr_Au=(1-b2)/(1+b2 ) ;
    rho_Au_Ma=(1-b3)/(1+b3 ) ;
    rho_Ma_buffer=(1-b4)/(1+b4 ) ;
    tau_glass_Cr=(2*(n1/n2 ))/(1+b1 ) ;
    tau_Cr_Au=(2*(n2/n3 ))/(1+b2 ) ;
    tau_Au_Ma=(2*(n3/n4 ))/(1+b3 ) ;
    tau_Ma_buffer=(2*(n4/n5 ))/(1+b4 ) ;
    H_glass_Cr=ones (2)/ tau_glass_Cr ;
    H_glass_Cr(1,2)=rho_glass_Cr / tau_glass_Cr ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_glass_Cr(2,1)=rho_glass_Cr / tau_glass_Cr ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Cr_Au=ones(2)/tau_Cr_Au ;
    H_Cr_Au(1,2)=rho_Cr_Au/tau_Cr_Au ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Cr_Au(2,1)=rho_Cr_Au/tau_Cr_Au ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Au_Ma=ones (2)/tau_Au_Ma ;
    H_Au_Ma(1,2)=rho_Au_Ma/tau_Au_Ma ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Au_Ma(2,1)=rho_Au_Ma/tau_Au_Ma ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Ma_buffer=ones (2)/ tau_Ma_buffer ;
    H_Ma_buffer(1,2)=rho_Ma_buffer/tau_Ma_buffer ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    H_Ma_buffer(2,1)=rho_Ma_buffer/tau_Ma_buffer ; %rho i s r e f l e c t i o n c o e f f i c i e n t s
    S_glass_buffer=H_glass_Cr*L_Cr*H_Cr_Au*L_Au*H_Au_Ma*L_Ma*H_Ma_buffer ;
    R_list(1,t )=( abs(S_glass_buffer ( 1 , 2 ) / S_glass_buffer ( 2 , 2 ) ) )^2 ;
    % vinkel (t)=theta /(2* pi ) * 3 6 0 ;
end
% figure(1) ;
% hold on
% plot(vinkel , R_list )
% [ sy , sx ]= s i z e ( R_l i s t ) ;
%
% for i =1:(sx-5)
% theta=the ta_start+deltatheta *(i -1);
% diff_R_list(i)=(-R_list(i)+R_list(i+5))/(5) ;
% diff_vinkel(i)=theta/(2* pi)* 360 ;
% end
%
% for i =1:(sx-6)
% theta=theta_start+deltatheta *( i-1);
% if sign ( diff_R_list ( i ))==sign ( diff_R_list (i +1))
% signchange (i)=0;
% else
% sign_note=theta /(2* pi )*360
% end
% end
%
% figure(2)
% plot ( diff_vinkel , diff_R_list )
end
function [ y_data ] = data_import(vinkel)
load SPR_data.txt ;
[sx,sy]= size(SPR_data) ;
for i =1:250
    y_data( i )=SPR_data( i +150 ,2)/7E4 ;
    %x_data( i )=i ;
end
x_data=vinkel ;
% hold on ;
%
% figure(2) ;
% plot( x_data , y_data )
end

[Walter Roberson]

You do not write a file of that name, so it is not obvious why you expect that the file will exist ?

Certainly it does not exist on the machines of the volunteers...

Answer 1

[SACHIN KHANDELWAL]

Hi Ananya,

After reviewing the error and the code you have provided, it appears that the issue arises because you are executing the script in the MATLAB Community.

If you have MATLAB installed, please ensure you are using the same working directory where the file 'SPR_data.txt' is located. Alternatively, you can use MATLAB Online to continue with your workflow.

I hope the information provided above will be helpful.

Thanks!