least square method.getting error using '\' or linsolve. pls help

any kind folks who can help me out. i'm trying to implement least square method, but i'm getting some error using linsolve and '\' function. please help, and million thanks in advance!

for a =1:400
    for P=1:49
        o=(P-1)*243; 
        for r=1:35
            if r==35
                t=-2;
                pA1(1:5,1,r,P)=A(7*r-6+o:7*r+t+o,a);
                pB1(1:5,1,r,P)=B(7*r-6+o:7*r+t+o,a);
                beta(r,P)=linsolve(pA1,pB1); <--- error
% beta(r,P)=pA1\pB1;

              else
                  t=0;
                  pA(1:7+t,1,r,P)=A(7*r-6+o:7*r+t+o,a);
                  pB(1:7+t,1,r,P)=B(7*r-6+o:7*r+t+o,a);
                  beta(r,P)=linsolve(pA,pB);; <---- error
% beta(r,P)=pA\pB;

              end

          end
      end

[Stephen23]

Can you please tell us what the complete error message is. We cannot read minds, and we also cannot read what is on your computer screen.

[seprienna]

many thanks for willing to help me out.

The complete message for linsolve is as follows:

   Error using linsolve
    First and second arguments must be 2D.

    Error in modifiedregression (line 34)
                    beta(r,P)=linsolve(pA,pB);

whereas for \ is as follows:

Error using  \ 
Inputs must be 2-D, or at least one input must be scalar.
To compute elementwise LDIVIDE, use LDIVIDE (.\) instead.

Error in modifiedregression (line 36)
 beta(r,P)=pA\pB;

Answer 1

[Matt J]

Your pA1 and pB1 are 4D arrays. However linsolve(A,B) expects A and B to be 2D matrices, and similarly for '\'.

[seprienna]

can you recommend a solution for least square method please? Manyt hanks in advance

[Matt J]

No, the intention of your code is not obvious. Don't you know what equations you want linsolve to solve? If it's now clear from my Answer that the data you're giving it is wrong, doesn't that tip you off as to what it should really be?

[seprienna]

i'm still trying to figure out a method to overcome the arrays to matrices. any tips from you? your kind reply is greatly appreciated

[Matt J]

Nope, no tips. We have no way of understanding what your code is trying to do unless you explain it to us.