Hi,
This error occours when the data vector you give, contains negetive values. Remove the negetive values and the error will be no more. For example
a = randn([1,10]); % It may give you negetive values
so histfit(a,10,'nakagami');
will give u error.
However a =randi(20,[1,30]); % It will give you only positive values
so histfit(a,10,'nakagami'); will not give u any error
Hope this helps.
Happy to help
UJJWAL