[Gsll-devel] how to make linear interpolation work?

The following snippet:

(let ((v1 #m(1d0 2d0 3d0)) (v2 #m(3d0 2d0 1d0))) (let ((interpolation (make-interpolation +linear-interpolation+ v1 v2)) (accel (make-acceleration))) (evaluate interpolation 2d0 :ya v2 :x1 v1 :acceleration accel)))

throws an error on SBCL (1.0.34):

There is no applicable method for the generic function #<STANDARD-GENERIC-FUNCTION C-ARRAY:ORIGINAL-ARRAY (1)> when called with arguments (NIL). [Condition of type SIMPLE-ERROR]

spline interpolation works. So, what am I missing?

Mirko