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POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
 

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  1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
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    <p>The Program below seems very inefficient. It takes as much as 28.980 GC time, in contrast 6.361 sec non-GC time, with SBCL 1.0.53.</p> <pre><code>(deftype vec3 () '(simple-array double-float (3))) (declaim (inline make-vec3 vec3-zero vec3-x vec3-y vec3-z vec3-+)) (defun make-vec3 (x y z) (declare (optimize (speed 3) (safety 0))) (make-array 3 :element-type 'double-float :initial-contents (list x y z))) (defun vec3-zero () (make-vec3 0.0d0 0.0d0 0.0d0)) (defun vec3-x (x) (declare (optimize (speed 3) (safety 0))) (declare (type (simple-array double-float (3)) x)) (aref x 0)) (defun vec3-y (x) (declare (optimize (speed 3) (safety 0))) (declare (type (simple-array double-float (3)) x)) (aref x 1)) (defun vec3-z (x) (declare (optimize (speed 3) (safety 0))) (declare (type (simple-array double-float (3)) x)) (aref x 2)) (defun vec3-+ (a b) (declare (optimize (speed 3) (safety 0))) (make-vec3 (+ (vec3-x a) (vec3-x b)) (+ (vec3-y a) (vec3-y b)) (+ (vec3-z a) (vec3-z b)))) ;; main (defun image (x y) (make-array (* x y) :element-type 'vec3 :initial-element (vec3-zero))) (defun add (to from val) (declare (type (simple-array vec3 (*)) to from) (type vec3 val) (optimize (speed 3) (safety 0))) (let ((size (array-dimension to 0))) (dotimes (i size) (setf (aref to i) (vec3-+ (aref from i) val))))) (defun main () (let ((to (image 800 800)) (x (make-vec3 1.0d0 1.0d0 1.0d0))) (time (dotimes (i 200) (add to to x))) (print (aref to 0)))) </code></pre> <p>time:</p> <pre><code>* (main) Evaluation took: 39.530 seconds of real time 35.340237 seconds of total run time (25.945526 user, 9.394711 system) [ Run times consist of 28.980 seconds GC time, and 6.361 seconds non-GC time. ] 89.40% CPU 83,778,297,762 processor cycles 46 page faults 6,144,014,656 bytes consed #(200.0d0 200.0d0 200.0d0) #(200.0d0 200.0d0 200.0d0) </code></pre> <p>Are there any approach to compute it in more efficient way, keeping the vec3 abstraction?</p> <p>For example, implementing Worker/Wrapper transformation using macro can eliminate the vec3 conses.</p> <p>As another way, making cons pool for vec3 will decrease the memory allocation.</p> <p>Ideally, it would be nice that SBCL supports non-descriptor representations for some data structure, like vec3, as array elements.</p>
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    1. PTQuestion
    1. USmasayuki takagi
    1. USmasayuki takagi
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      1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
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    2. VO
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      1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
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      1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
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      1. VTUpMod
    1. COMaybe here you'll be able to find hints for improving performance: http://random-state.net/log/3530433886.html
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      1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
      1. USVsevolod Dyomkin
    2. COThanks. It's not about structured data like the vec3, but flat floating point operations.
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      1. POEfficient vector operations of linear algebra in Common Lisp, especially SBCL?
      1. USmasayuki takagi
 

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