> I've try as suggested, but the plugin still giving wrong answer. Meantime, I
> tried to change all data type into double, turn up the VM crashed. What are
> the possible errors, and why the VM crashed when I change data
> representation into double?
> 
> Any help will be very much appreciated. Thanks

  What are bVector and xVector?  What class(es) are they?  If they are
FloatArrays changing the types to double is not a right thing.
What does loadArgumentVector: do?

  Ah, but the problem seems that you are missing the type declaration
of ratio and temp in solveGauss:with:into:.  Upon the assignments to
them in C, the values will be truncated.

-- Yoshiki