On Oct 4, Dave Herman wrote:
> > No! 'identifier?' does not check whether a syntax object represents
> > a variable reference, given 1) identifier macros and 2) #%top
> > transformers for unbound variables. If you really, really want to
> > check if something is a variable reference, 'local-
>
> No! 'identifier?' does not check whether a syntax object represents a
> variable reference, given 1) identifier macros and 2) #%top transformers for
> unbound variables. If you really, really want to check if something is a
> variable reference, 'local-expand' it and look at the result.
>
Will
No! 'identifier?' does not check whether a syntax object represents
a variable reference, given 1) identifier macros and 2) #%top
transformers for unbound variables. If you really, really want to
check if something is a variable reference, 'local-expand' it and
look at the result.
Oh, yes
Dave Herman wrote:
;;; (real->float x) -> inexact-real?
;;; x : real?
;;; Returns an inexact real (i.e., a float) given real x. Raises an
error if x
;;; is not a real. This can be used to ensure a real value is a float,
even in
;;; unsafe code.
(define (real->float x)
(if (real? x)
(
When I was originally thinking about it, I was thinking a macro, too. I like
the real->float as an exported function for simplicity - I think most users
of the science collection would be more comfortable with it in their own
code. But I like the syntax of the following macro.
(define-syntax (with
On Oct 4, Dave Herman wrote:
> I'm not sure whether the mzscheme compiler obeys the Macro Writer's
> Bill of Rights in optimizing the case where exp is just a variable
> reference.
-> (compile '(define (fib1 n) (if (<= n 1) n (+ (fib1 (- n 1)) (fib1 (- n
2))
#~
-> (compile '(define (fib
;;; (real->float x) -> inexact-real?
;;; x : real?
;;; Returns an inexact real (i.e., a float) given real x. Raises an
error if x
;;; is not a real. This can be used to ensure a real value is a
float, even in
;;; unsafe code.
(define (real->float x)
(if (real? x)
(exact->inexact x)
I added real->float in the math functions in the science collection that
I'll call.
;;; (real->float x) -> inexact-real?
;;; x : real?
;;; Returns an inexact real (i.e., a float) given real x. Raises an error if
x
;;; is not a real. This can be used to ensure a real value is a float, even
in
;;;
At Sun, 4 Oct 2009 14:46:48 -0400, Doug Williams wrote:
> When you use mutable data structures, you live with the choice. For the
> statistics routines, I use exact->inexact inside the loop at the point where
> I use the value, so I'm not worried about it. Off the top of my head, the
> only problem
I have implemented the changes in the statistics, Chebyshev evaluation, and
ordinary differential equation solver routines in the science collection.
They work under the pre-release 4.2.2 (4.2.1.900) and the latest nightly
build (4.2.2.4). I will put the new version on the Schematics site, but not
When you use mutable data structures, you live with the choice. For the
statistics routines, I use exact->inexact inside the loop at the point where
I use the value, so I'm not worried about it. Off the top of my head, the
only problem I see is that exact->inexact also works on complex numbers, so
At Sat, 3 Oct 2009 08:34:03 -0600, Matthew Flatt wrote:
> (while the contract on the "checked" version ensures that the unsafe
> operations will not cause a crash).
Not true. Sam points out that a vector (or other sequence) can be
mutable, so checking elements at the beginning does not make `varia
At Sat, 3 Oct 2009 16:54:26 -0400, Doug Williams wrote:
> One more thing. Is there a one argument unsafe-fx- and unsafe-fl- to negate
> a fixnum or float? [I suppose the same question would apply to
> division/inversion, although I don't use it as much.] Obviously, I can use
> (unsafe-fl- 0.0 x) fo
At Sat, 3 Oct 2009 15:27:57 -0400, Doug Williams wrote:
> Do you think you can sneak in unsafe-fx-abs and unsafe-fl-abs?
Added in 4.2.2.4 (which is the most recent nightly build).
_
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http://list.cs.brown.edu
One more thing. Is there a one argument unsafe-fx- and unsafe-fl- to negate
a fixnum or float? [I suppose the same question would apply to
division/inversion, although I don't use it as much.] Obviously, I can use
(unsafe-fl- 0.0 x) for (unsafe-fl- x).
On Sat, Oct 3, 2009 at 4:07 PM, Matthew Flatt
Yes, I can add those.
At Sat, 3 Oct 2009 15:27:57 -0400, Doug Williams wrote:
> Matthew,
>
> Do you think you can sneak in unsafe-fx-abs and unsafe-fl-abs? It's a pretty
> common function - at least in the science collection - that I assume would
> compile nicely. [I promise not to ask for too ma
Matthew,
Do you think you can sneak in unsafe-fx-abs and unsafe-fl-abs? It's a pretty
common function - at least in the science collection - that I assume would
compile nicely. [I promise not to ask for too many of these.]
Doug
On Sat, Oct 3, 2009 at 12:56 PM, Matthew Flatt wrote:
> `inexact-r
`inexact-real?'
At Sat, 3 Oct 2009 12:47:35 -0400, Doug Williams wrote:
> Is there an existing contract to check for a float? For example, mean would
> now be guaranteed to return a float instead of a real. It would be nice to
> specify this is the contract.
>
> On Sat, Oct 3, 2009 at 12:36 PM, M
Is there an existing contract to check for a float? For example, mean would
now be guaranteed to return a float instead of a real. It would be nice to
specify this is the contract.
On Sat, Oct 3, 2009 at 12:36 PM, Matthew Flatt wrote:
> At Sat, 3 Oct 2009 12:29:01 -0400, Doug Williams wrote:
> >
At Sat, 3 Oct 2009 12:29:01 -0400, Doug Williams wrote:
> Are the basic unsafe-fl, unsafe-fx, and unsafe-vector-ref operations
> included in 4.2.2?
Yes --- except for `unsafe-fx->fl', which is new in 4.2.2.3.
_
For list-related administrative task
About a 2x speed improvement is worth the rewrite. And, in the case of the
statistics functions, for example, most always return a float result (even
with non-float inputs) and would benefit from the rewrite. [Most that don't
always return a float, like minimum and maximum, aren't don't much
comput
As of v4.2.2.3 (in SVN), the JIT can unbox some intermediate flonum
values in `unsafe-fl' combinations. For example, in
(unsafe-fl+ 1.0 (unsafe-fl- x y))
the JIT can see that `unsafe-fl-' will produce a flonum while
`unsafe-fl+' consumes a flonum, so there is no reason to box the flonum
and then
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