MATLAB: Can’t use KummerU function

confluent hypergeometric functionkummeru

Hi, When I try to use builtin kummerU function, it gives me "Undefined function 'kummerU' for input arguments of type 'double'." Needed package is installed, and I don't understand why can't the function use real number instead of complex with zero imaginary part.
Help!
Daniel

Best Answer

Hi,
kummerU is a Symbolic Math Toolbox function, so you can't simply call:
>> kummerU(1/3, 2.0, -50)
Undefined function 'kummerU' for input arguments of type 'double'.
You have to call:
>> evalin(symengine,'kummerU(1/3, 2.0, -50)')
ans =
0.13511493810668281560142994786047 - 0.23402593766229884316074691432347*i
Or use feval:
>> feval(symengine,'kummerU',1/3, '2.0', -50)
ans =
0.13511493810668281560142994786047 - 0.23402593766229884316074691432347*i
I used '2.0' in order to get a floating-point value otherwise you would get:
>> feval(symengine,'kummerU',1/3, 2.0, -50)
ans =
kummerU(1/3, 2, -50)
This is explained here:
http://www.mathworks.com/help/symbolic/call-built-in-mupad-functions-from-the-matlab-command-window.html
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