Operands to the || and && operators must be convertible to logical scalar values.

I have a problem with my coding about Operands to the || and && operators must be convertible to logical scalar values.. Here in detail:

for i=1:length(FS);
  depth_all7=[]
  if FS < 1 && Depth<20;  
    LPi= (1-FS(i))*(J - K*Depth(i));
  elseif FS>= 1 && Depth > 20
    LPi= 0;
  elseif FS <=1 && Depth>=20
    LPi = 0;    
  elseif FS >=1 && Depth<=20
    LPi= 0;  
    depth_all7=[depth_all7;LPi]
  end     
  fprintf(fid_X,'%2.4f  %2.4f  %2.4f %2.4f %2.6f %10s\n', Depth(i),CSR(i), CRR(i), FS(i), LPi(i), teks_i);
end

Is there any one can help me?

Answer 1

[dpb]

Presuming FS and Depth are vectors, then you need to subscript them as, for example

 if FS(i) < 1 && Depth(i)<20

in all expressions...otherwise FS<1 or Depth>=20 return logical vectors of size(FS) or size(Depth)

You can do the assignments using logical addressing without the loop...note as you've written the loop that the depth_all7 array will be equivalent to

     depth_all7=zeros(sum(FS>=1 & Depth<=20,1));

so numel() will be the number of cases that satisfy the condition, not the same size as Fs. If that is the intent, that's fine.

The first conditional case is peculiar -- if LPi is a single value not a predefined array, then it is overwritten each pass through the loop and otherwise never used. One would guess that isn't the intent.

[Skydriver]

Should I change the first depth_all7 = [ ] become depth_all7=zeros(sum(FS>=1 & Depth<=20,1));

If yes the result is:

Error using &

Matrix dimensions must agree.

Error in PDF_Repi_Mw_amax_PGA_YogyaNew (line 407)

depth_all7=zero(sum(FS>=1 & Depth<=20,1)

[dpb]

"Should I change the first depth_all7 = [ ] become depth_all7=zeros(sum(FS>=1 & Depth<=20,1));"

No! Remove it entirely; the latter (presuming you move it all outside the loop) allocates the whole array on assignment. As noted, the length of the result is dependent upon the data.

Also, the function is zeros, not zero; your reference causing the error looks like a subscript expression on an variable.

[dpb]

You also did not address the other question regarding what is LPi and what are you trying to compute overall?

[Skydriver]

Thank you finnaly resolved "dpb"