Access matrix values inside of a function
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Hi MATLAB-Folks,
I'm asking with a beginner problem for your help, I searched the forum for an answer but without sucess:
I have a script, that creates a vector, lets say as an example:
>> g_x_contact=[0 0 1 2 3 4 0 0]
afterwards I'm creating a function, that uses the corresponding value of the vector within.
For example:
function Integral = pressure_integral(x)
Integral = g_x_contact(x).*(x/2)
end
So I want the function to use the value at position x and calculate the according steps afterwards.
Here the promt-line >> pressure_integral(6) should calculated with the sixth element: 4.*(6/2)=12
Instead I get the error-Message
Unrecognized function or variable 'g_x_contact'.
Error in pressure_integral (line 6)
Integral = g_x_contact(x).*(x/2)
Can anybody give me a hint, how the access the Vector?
Thank you in advance and very best
Christian
采纳的回答
Bob Thompson
2021-3-2
编辑：Bob Thompson
2021-3-2
0 个投票
I believe this is the purpose of global variables, but I could be wrong. I don't really use them much.
5 个评论
Stephen23
2021-3-2
Much better than global variables (which should be avoided):
- nested functions
- passing data as input argument (recommended by the MATLAB documentation).
Christian S.
2021-3-2
Thank you for your answers Bob and Stephen,
I came across the method of passing data as an input. I thought my targeted use for this fuction -to calculate an integral- will be problematic, if I give the function two input arguments.
My detailed explenation:
The p(Xi) is my precalculated Vector with different values.
Is it expedient to do this with the method of passing data?
Very best
Christian
Bob Thompson
2021-3-2
Stephen, good to know. So glad they taught me good code practices in school.
Christian, why don't you just pass in the extra variable?
function Integral = pressure_integral(x,g_x_contact)
Integral = g_x_contact(x).*(x/2)
end
"I thought my targeted use for this fuction -to calculate an integral- will be problematic, if I give the function two input arguments."
It isn't problematic at all. This explains what you need:
Christian S.
2021-3-4
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