fitlm works but polyfit does not work

I run polyfit and fitlm for the same data. fitlm provides an output. But polyfit and corrcoef return NaN. How can it be?

[Catalytic]

Who knows? You've provided no means for us to reproduce what you see.

Answer 1

[Ameer Hamza]

There is probably NaN somewhere in your dataset. fitlm() ignores those data values. For example

x = linspace(0, 1, 10);
y = 2*x + 3 + rand(size(x));
y(3) = nan;

p = polyfit(x, y, 1)
c = corrcoef(y)
ft = fitlm(x, y)

Result

>> p
p =
   NaN   NaN
>> c
c =
   NaN
>> ft
ft = 
Linear regression model:
    y ~ 1 + x1

Estimated Coefficients:
                   Estimate      SE       tStat       pValue  
                   ________    _______    ______    __________
    (Intercept)     3.1773     0.13254    23.973    5.5901e-08
    x1              2.3847     0.21348     11.17    1.0268e-05

Number of observations: 9, Error degrees of freedom: 7
Root Mean Squared Error: 0.206
R-squared: 0.947,  Adjusted R-Squared: 0.939
F-statistic vs. constant model: 125, p-value = 1.03e-05

[alpedhuez]

Thank you.

[Ameer Hamza]

I am glad to be of help!