Large matrix for surface plot?

Question

I'm somewhat new to MATLAB and I'm trying to make a large matrix structured very much like the following example:

C=[1,2,3] 
n=[-3,0,3]
X=[f(1,-3),f(1,0),f(1,3);f(2,-3),f(2,0),f(2,3);f(3,-3),f(3,0),f(3,3)]

where f is some function of the values in C and n. I need this sort of matrix, X, so that I can make a surface graph of surf(C,n,X). The issue is that, in my real problem, I need a 51x51 matrix, and I don't know how to make such a matrix without typing out everything (which would be a horrific task).

Could someone please help me understand how to make such a plot? Thank you so much!

Does f operate element-wise on array inputs as well as just a pair of scalars (e.g. f(1,1)) as you have shown? — chappjc
– chappjc, Commented Feb 25, 2014 at 1:03

chappjc · Accepted Answer · 2014-02-25 01:05:13Z

0

Have a look at ndgrid:

>> [ii,jj] = ndgrid(C,n)
ii =
     1     1     1
     2     2     2
     3     3     3
jj =
    -3     0     3
    -3     0     3
    -3     0     3

Then you can get X very easily if f operates element-wise on non-scalar inputs:

X = f(ii,jj);

If f can only take a pair of scalars, try arrayfun:

X = arrayfun(@(x,y)f(x,y),ii,jj);

(Or modify f!)

answered Feb 25, 2014 at 1:05

chappjc

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War10ck · Accepted Answer · 2014-02-25 01:10:19Z

0

X = f(C'*ones(1, 51), ones(51, 1)*n))

edited Feb 25, 2014 at 1:10

War10ck

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answered Feb 25, 2014 at 0:44

Bob Brandt

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1 Comment

user3349053 Over a year ago

I'm sorry; I can't seem to make this work. Could you please elaborate or provide a link that gives more insight into this?

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