Plotting a surface from a two-dimensional matrix

Good day, I have the following problem:

I've run a simulation that produces some signals depending on two variables. As my advisor told me, I made a python pipeline that saves the simulated signals on a file in a two-dimensional matrix, with the first two columns being the sweeps of the two variables in all the possible permutations. For example. assuming that the two variables have values [1 2 3] and [4 5 6], the first two columns would be:

[1 4]

[1 5]

[1 6]

[2 4]

[2 5]

[2 6]

[3 4]

[3 5]

[3 6]

Now i have to plot these signals on surfaces on a 3d plot. From what I know, to plot a surface one needs the "surf" command, that takes two vectos with dimensions N and M, plus a two-dimensional matrix with dimensions N x M. The only way that i can think of to obtain this in my case would be to build a new data matrix from scratch using a for cycle, to assign the values of the error signals to two-dimensional matrix, but it seems unefficient and lenghty. Am i missing something?

[KSSV]

x = [1 2 3] ;
y = [4 5 6] ;
[X,Y] = meshgrid(x,y) ; 
Z = sqrt(X.^2+Y.^2) ; 
surf(X,Y,Z)

Okay, you have x, y but what about Z?

[Mattia Boldrini]

so i cna use my already mashed grid as [X,Y]? all the other columns of the table are each a Z, each file contains multiple surfaces that i have to plot.

Answer 1

[Deepak Meena]

Hi Mattia ,

Since we want to have permutation for the create the Surface plot , mex grid will of great use. It returns 2-D grid coordinates based on the coordinates contained in vectors x and y. X is a matrix where each row is a copy of x, and Y is a matrix where each column is a copy of y. The grid represented by the coordinates X and Y has length(y) rows and length(x) columns.

so for your example x = [1 2 3 ] & y = [4 5 6]

>> X

X =

     1     2     3
     1     2     3
     1     2     3

>> Y

Y =

     4     4     4
     5     5     5
     6     6     6

>> 

so we run

F = X.*exp(-X.^2-Y.^2);
surf(X,Y,F)

It plots for all the possible pairs of x and y. Since you have already a Z value associated value with them , you can plot the surface plot

Thanks