Inline C for Common Lisp


Inline C is an idea taken from Lush - namely, the ability to just switch over to C when anything is slow or awkward in plain LISP. This is particularly useful when using outside libraries, because no LISP bindings are necessary.


Here's an example of the usage (taken from the examples file, test-cinline.lisp):
(defun symm-eigenvals (matrix)
  "Use GSL and BLAS to find the eigenvalues of a symmetric matrix

Usage: (symm-eigenvals
         (make-array 4 :initial-contents '(1d0 2d0 2d0 1d0)
                       :element-type 'double-float))
==>    #(3.0000000000000004d0 -1.0000000000000002d0)
  (declare (type (simple-array double-float (*)) matrix))
  (let* ((n^2 (length matrix))
         (n-r (multiple-value-list (floor (sqrt n^2))))
         (n   (if (zerop (cadr n-r)) (car n-r) (error "matrix isn't square")))
         (eivals (make-array n :element-type 'double-float)))
    (cin:cinline ((double* matrix) (uint n) (double* eivals))
#include <gsl/gsl_math.h>
#include <gsl/gsl_eigen.h>
gsl_matrix_view m = gsl_matrix_view_array ($matrix, $n, $n);
gsl_vector_view o = gsl_vector_view_array ($eivals, $n);
gsl_eigen_symm_workspace *w = gsl_eigen_symm_alloc ($n);

gsl_eigen_symm (&m.matrix, &o.vector, w);
gsl_eigen_symm_free (w);
                 ("gsl" "blas"))


Right now, Inline C is only implemented for CMUCL and SBCL. UFFI was my first choice, but it doesn't give you access to the data pointer in a vector.

Future Direction

Damn have to run

OK I'll put up more whenever I get a chance but for now you can find everything on my web page: here.

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