# Arrays have incompatible sizes for this operation

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Miguel Albuquerque on 12 Jul 2022
Im trying to apply this equation on matlab However i Keep getting this error , arrays have incompatible sizes for this operation, I dont understand since there are only constants and when there is a vector I do this .*
This is the code:
D is not getting any error, only H_BAC.
I ve attached the data
n=1;
u=2;
Lp=1;
fc=30e6;
c=3e8;
Vr=250;
D=sqrt(1-((u.^2*doppler_freqSurv.^2*c.^2)/4*Vr.^2*fc.^2));
H_BAC=exp(1*j*2*pi*((R1_matrix-Rm_matrix+n*Lp)/c*fc .*D));

Voss on 12 Jul 2022
R1_matrix and Rm_matrix are 1x400:
whos R*
Name Size Bytes Class Attributes R1_matrix 1x400 3200 double Rm_matrix 1x400 3200 double
Therefore, the expression involving subtracting Rm_matrix from R1_matrix gives a 1x400 vector (here stored as the variable temp):
n=1;
u=2;
Lp=1;
fc=30e6;
c=3e8;
Vr=250;
temp = (R1_matrix-Rm_matrix+n*Lp)/c*fc;
whos temp
Name Size Bytes Class Attributes temp 1x400 3200 double
The result of that expression should be multiplied element-wise by D, but D is 1x8000:
whos D
Name Size Bytes Class Attributes D 1x8000 128000 double complex
So you can't do it:
H_BAC=exp(1*j*2*pi*(temp.*D));
Arrays have incompatible sizes for this operation.
Hard to say what the right thing to do is with the information given.
Miguel Albuquerque on 12 Jul 2022
Here it is the best way, thanks anyways
R1_matrix(numel(D))=0;

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