Reformat of code, Rewriting code and adding some changes

Does anyone have any ideas of how I code write this code differently? Like is there any substitues for the matlab based functions that I am calling, Even if it makes the code longer Ill accept the answer.

function [t,cp]=CpRange(tmin,tmax,inc)
inc=round(inc,3);%rounding to 3 decimal points
t=tmin:inc:tmax;
cp=zeros(size(t));
for i=1:length(cp)
cp(i)=CO2(t(i));
end
end

[Voss]

What is CO2? And what is your objective in wanting to rewrite this? To speed it up?

[Owen Fernandez]

CO2 represents a data calculation

here is the other function for CO2 and yes to speed it up

function cp=CO2(t)
R=.1889;
if t>=300 && t<=1000
cp=0.24007797e+01+0.87850957e-02*t-0.6607878e-05*t^2+0.20021861e-08*t^3+0.63274039e-15*t^4;
elseif t>1000 && t<=3000
cp=0.44080e+1+0.309817e-02*t-0.123925e-05^t^2+0.227413e-09*t^3-0.155259e-13+t^3;
end
cp=cp*R;
end

[Voss]

Vectorizing the CO2 calculation should speed it up. You can use logical indexing to do that:

function [t,cp]=CpRange(tmin,tmax,inc)

inc=round(inc,3);%rounding to 3 decimal points

t=tmin:inc:tmax;
cp=zeros(size(t));
R=.1889;

idx = t>=300 & t<=1000;
cp(idx) = 0.24007797e+01 ...
    +0.87850957e-02*t(idx) ...
    -0.6607878e-05*t(idx).^2 ...
    +0.20021861e-08*t(idx).^3 ...
    +0.63274039e-15*t(idx).^4;

idx = t>1000 & t<=3000;
cp(idx) = 0.44080e+1 ...
    +0.309817e-02*t(idx) ...
    -0.123925e-05.^t(idx).^2 ...
    +0.227413e-09*t(idx).^3 ...
    -0.155259e-13+t(idx).^3;

cp=cp*R;

Also, check your second formula (for t > 1000 and <= 3000); I think maybe there are two typos (^t^2 should perhaps be *t^2 and +t^3 should perhaps be *t^4).

[Owen Fernandez]

Thank you Mr. BenJamin that really helped me (: