How can I change multiple variable name within a loop, while assigning those variables as matrix values?

I have a n x 3 matrix called dataMat. I also have n amount of processes that this code will eventually be able to handle. Each process has a n value (n), pressure (p) and volume (v). I want to be able to calculate the work done using 1 of two formulas-formula chosen based on if n=1 or not. My code is below, I don't know how to change the variable names while pulling data from the matrix at the same time.

n=size(dataMat,1);
for i=1:n
   Cyc(i)n=dataMat(n,1);
   Cyc(i)p=dataMat(n,2);
   Cyc(i)v= dataMat(2,3);
end

formulas: if n=1 W=(P1)(V1)ln(V2/V1)

if not W=(P2*V2-P1*V1)/1-n1

[John BG]

please

1.

confirm that your line

Cyc(i)v= dataMat(2,3);

should be

   Cyc(i)v= dataMat(n,3);

2. is the Work formula

W=(P2*V2-P1*V1)/1-n1

supposed to be something like

W=(P2*V2-P1*V1)/(n2-n1)

[Krish Desai]

Your edits to #1 are correct. #2 is correct as is, with (1-n1) as the denominator.

[Stephen23]

Creating variables names in a loop is a really bad idea, because it creates slow buggy code:

https://www.mathworks.com/matlabcentral/answers/196952-how-to-create-new-variables-in-batches-with-strcat

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

Answer 2

[John BG]

the initial extraction does not need a for loop:

Cyc_n=dataMat(:,1);
Cyc_p=dataMat(:,2);
Cyc_v=dataMat(:,3);

Since it looks like the syntax of the formulas needs improving, I guess your are trying to differentiate,

    W=zeros(1,length(Cyc_v))
  for k=2:1:length(Cyc_n)
       W(k-1)=Cyc_p(k-1)*Cyc_v(k-1)*log(Cyc_v(k)/Cyc_v(k-1))
    end

or

    for k=2:1:length(Cyc_n)
       W(k-1)=Cyc_p(k)*Cyc_v(k)-Cyc_p(k-1)*Cyc_v(k-1)/(Cyc_n(k)-Cyc_n(k));
    end

Krish, if you find this answer useful would you please be so kind to mark my answer as Accepted Answer?

To any other reader, please if you find this answer of any help solving your question,

please click on the thumbs-up vote link,

thanks in advance

John BG

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