??? Index exceeds matrix dimensions.
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I have a matlab file (m-file) with the operation for spatial regression from my teacher (I also have a .txt file data333 for all data of sample points), it looks like this:
%*********Spatiell regression******** %***This program calculates a new value (z*) for each value (zi)in a table and %***account for all other values (zj). These other values (zj)are weighted with the %****squared distance (1/d^2). %***In this version, we only use values that are within a specific radius %***chosen by the user. e.g "d<30" %***The program calculates new z for the same number of columns that the input file has got. %*** % % % % % clear format long % load C:\tempdata\data333.txt col=0; raa=0.05; d=0; c=0; n=0; w=0; b=0; data4=zeros(220,10);
for col=3:12
for i=1:220
b=0;
c=0;
for j=1:220
if i~=j
d=sqrt((data333(i,1)-data333(j,1))^2+(data333(i,2)-data333(j,2))^2);
if d<30
c=(1/(d^2))*data333(j,col);
b=b+c;
else
end
end
end
x=data333(i,col) - (raa * b);
n=i;
data4(i,col)= x;
data4(i,1)=n;
end
% dlmwrite('trash.txt',data4,'\t') dlmwrite('data333-100spreg2-raa05.txt',data4,'\t') end
I thus just copied those steps except I wrote data333=importdata ('C:\tempdata\data333.txt') instead of use Load. This is because everytime I use Load, I got error messages :"Undefined function or variable xxx" or "Undefined function or method 'data333' for input arguments of types 'double' ” etc.
After I wrote data333=importdata ('C:\tempdata\data333.txt')I got: data333 =
data: [220x12 double]
textdata: {'x' 'y' 'DEM' 'asp' 'grad' 'DAI2' 'HI' 'VI' 'SLI2' 'Yield' 'DAI1' 'SLI1'}
colheaders: {'x' 'y' 'DEM' 'asp' 'grad' 'DAI2' 'HI' 'VI' 'SLI2' 'Yield' 'DAI1' 'SLI1'}
Then I copied the rest and ran MATLAB, an error message appeared: Index exceeds matrix dimensions.
I never used MATLAB before and suddently I have to hand in this assignment within 3 days! Could somebody help me to figure it out? Thanks!!!
Yaoyao
Answers (1)
Roger Stafford
on 16 Sep 2014
I suspect the trouble lies with 'data333'. It may not have as many as 12 columns. If not, the lines "c=(1/(d^2))*data333(j,col);" and "x=data333(i,col) - (raa * b);" would be accessing non-existent data in 'data333'. To check this ask for size(data333) after it is loaded.
Also the line "data4(i,col)= x;" indicates an unplanned expansion of 'data4' which was originally only provided with 10 columns. There's something fishy there.
9 Comments
Hikaru
on 17 Sep 2014
Make sure you input the correct filename when using readtable, I used exercise-data333.txt because it was provided in your zip file, but I don't really know which files you were supposed to use. I also used T as a random variable name, it looks like in your program, it should be named as data333 ?
And like Star mentioned above, you will have to convert the table into a matrix by using the table2array function.
I ran it on my machine and it didn't produce any error.
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