I'm not exactly sure what you are trying to do, but you are being very careless with your indeces. For starters:
- A is a 4x3 matrix
- B is a 6x3 matrix
- C is a 3x3 matrix
- already_plotted is a 3x3 matrix
- L is a 3x1 matrix
What values of A and B did you want to plot?
- A(L) is using a 3x1 matrix to index values from a 4x3 matrix.
- B(L) is using a 3x1 matrix to index values from a 6x3 matrix.
- Also, L is a variable generated based on C. How is that suppose to relate back to A and B?
Similarly, what is the intended outcome of this code?
- already_plotted(L)=true is assigning a 1x1 value to a 4x3 matrix using a 3x1 index.
- L= C(:,1) == 10 & ~already_plotted; is using an & to combine a 3x1 condition and a 3x3 condition
The point is you have to be much more explicit about what values you want.