Re: Identifying sources of allocations in a toy Mandelbrot package

[Tomas Hlavaty]

in lisp, a rough heuristic is that anything can allocate memory anytime

another useful heuristic is not to do things that do not need to be
done (not lisp-specific)

>> You have a pretty big vector
>
> The vector is allocated once and not on the same scale as usage,
> measured by profiling or by resident memory in top.

it does not need to be allocated at all

>     (eval-when-compile (require 'cl-lib))

have you tried eliminating cl-lib?

>         (let* ((cx) (cy) (zr) (zi) (v) (out) (zrt)
                 ^
                 those parens are unnecessary

also it is ugly to (let (a) (setq a 42) ...)

it is nice to put let around as little forms as possible
then the binding dependencies look clearer
and lack of setf and setq means
I don't have to think unnecessarily about sideeffects

>                (output (make-vector (* w h 3) 0))

you dont need the output vector at all, you already have an output
buffer so just write there directly

>               (setf cx (+ x0 (* dxp x)))

use let instead of setf and setq, everywhere

>                         (if (> (+ (* zr zr) (* zi zi)) 4) (cl-return v)

avoid cl-return

>               (aset output idx out)
>               (aset output (+ idx 1) out)
>               (aset output (+ idx 2) out)

insert the value into the output buffer here