How to apply the white point when converting xyz to upvpl using 'makecform'?

Hi,

I have a sample data point with XYZ values shown below.

XYZ = [29.5400   25.2800   19.5900];

I would like to convert XYZ to Luv using 'makecform' with type of 'xyz2upvpl'.

My code is shown below.

cform = makecform('xyz2upvpl');
upvpl = applycform(XYZ, cform);

I then got the result

>> upvpl

upvpl =

    0.2527    0.4867   25.2800

The result doesn't seems right to me since L = 25.2800 which is the same as Y which is also 25.2800.

There is no reason that L = Y. I must have done something wrong. Is it to do with the missing information on the white point? How can I define the white point for the type of 'xyz2upvpl'?