Re: [Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-12-05 Thread Ei-ji Nakama 
hello,

i read this pdf (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1950.pdf)
i think ... x to be integer only(more accurate value).

following test code and patch.
### F.10.1.12 The cospi functions
## cospi(+-0)  : 1, 1
cospi(c(+0,-0))
## cospi(n + 1/2)  : all 0
cospi((-4:4)+.5)
## cospi(+-Inf): NaN
cospi(c(+Inf,-Inf))
## cospi(n)
cospi((-4:4))

### F.10.1.13 The sinpi functions
## sinpi(+-0)  :+0,-0
sprintf("%a",sinpi(c(+0,-0)))
## sinpi(n + 1/2)  : all 0
sinpi((-4:4))
## sinpi(+-Inf): NaN
sinpi(c(+Inf,-Inf))
## sinpi(n):1 -1  1 -1  1 -1  1 -1  1
sinpi((-4:4+.5))

### F.10.1.14 The tanpi functions
## tanpi(+-0)   :+0,-0
sprintf("%a",tanpi(c(+0,-0)))
## tanpi(pos even and neg odd)  :+0
sprintf("%a",tanpi(c(-3,-1,2,4)))
## tanpi(pos odd and ned even)  :-0
sprintf("%a",tanpi(c(-4,-2,1,3)))
## tanpi(n+1/2) n = even:+Inf
tanpi(c(1:3*2)+.5)
tanpi(c(1:3*2)*-1+.5)
## tanpi(n+1/2) n = odd :-Inf
tanpi(c(1:3*2+1)+.5)
tanpi(c(1:3*2+1)*-1+.5)

## tanpi(+-Inf) :NaN NaN
tanpi(c(+Inf,-Inf))

## no integer
sinpi(1.23e23) # 0.4652223
cospi(1.23e23) # 0.8851939
tanpi(1.23e23) # 0.5255597



--- R-3.3.2.orig/src/nmath/cospi.c2016-09-15 07:15:31.0 +0900
+++ R-3.3.2/src/nmath/cospi.c2016-12-05 21:29:20.764593514 +0900
@@ -21,13 +21,10 @@
The __cospi etc variants are from macOS (and perhaps other
BSD-based systems).
 */

-#ifdef HAVE_COSPI
-#elif defined HAVE___COSPI
-double cospi(double x) {
-return __cospi(x);
-}
+
+#if defined(__STDC_WANT_IEC_60559_FUNCS_EXT__) &&
__STDC_WANT_IEC_60559_FUNCS_EXT__ >= 201506L
+/* use standard cospi */
 #else
-// cos(pi * x)  -- exact when x = k/2  for all integer k
 double cospi(double x) {
 #ifdef IEEE_754
 /* NaNs propagated correctly */
@@ -35,7 +32,11 @@
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

-x = fmod(fabs(x), 2.);// cos() symmetric; cos(pi(x + 2k)) ==
cos(pi x) for all integer k
+x = fabs(x);
+if ( x > 9007199254740991 ) /* 2^53-1 */
+return cos(M_PI * x);
+
+x = fmod(x, 2.);// cos() symmetric; cos(pi(x + 2k)) == cos(pi x)
for all integer k
 if(fmod(x, 1.) == 0.5) return 0.;
 if( x == 1.)return -1.;
 if( x == 0.)return  1.;
@@ -44,11 +45,8 @@
 }
 #endif

-#ifdef HAVE_SINPI
-#elif defined HAVE___SINPI
-double sinpi(double x) {
-return __sinpi(x);
-}
+#if defined(__STDC_WANT_IEC_60559_FUNCS_EXT__) &&
__STDC_WANT_IEC_60559_FUNCS_EXT__ >= 201506L
+/* use standard cospi */
 #else
 // sin(pi * x)  -- exact when x = k/2  for all integer k
 double sinpi(double x) {
@@ -57,6 +55,12 @@
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

+if (( x >  9007199254740991 )||  /*  2^53-1 */
+( x < -9007199254740991 )  ) /* -2^53-1 */
+return sin(M_PI * x);
+
+if( x == 0 || x == -0 )
+return(x);
 x = fmod(x, 2.); // sin(pi(x + 2k)) == sin(pi x)  for all integer k
 // map (-2,2) --> (-1,1] :
 if(x <= -1) x += 2.; else if (x > 1.) x -= 2.;
@@ -69,26 +73,50 @@
 #endif

 // tan(pi * x)  -- exact when x = k/2  for all integer k
-#if defined(HAVE_TANPI) || defined(HAVE___TANPI)
+#if defined(__STDC_WANT_IEC_60559_FUNCS_EXT__) &&
__STDC_WANT_IEC_60559_FUNCS_EXT__ >= 201506L
+/* use standard cospi */
 // for use in arithmetic.c, half-values documented to give NaN
-double Rtanpi(double x)
 #else
 double tanpi(double x)
-#endif
 {
+  int _sig=0;
+  int _even=0;
+  int _odd=0;
+  int _int=0;
 #ifdef IEEE_754
 if (ISNAN(x)) return x;
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

-x = fmod(x, 1.); // tan(pi(x + k)) == tan(pi x)  for all integer k
-// map (-1,1) --> (-1/2, 1/2] :
-if(x <= -0.5) x++; else if(x > 0.5) x--;
-return (x == 0.) ? 0. : ((x == 0.5) ? ML_NAN : tan(M_PI * x));
+if (( x >  9007199254740991 )||  /*  2^53-1 */
+( x < -9007199254740991 )  ) /* -2^53-1 */
+return tan(M_PI * x);
+
+if( x == 0. || x == -0. )
+return(x);
+if(x>0) _sig = 1;
+if(x<0) _sig =-1;
+
+x = fmod(x, 2.);
+if(( x == 0.0 )||( x == -0.0)){ _even = 1; _int=1;}
+if(( x == 0.5 )||( x == -0.5))  _even = 1;
+if(( x == 1.0 )||( x == -1.0)){ _odd = 1;  _int=1;}
+if(( x == 1.5 )||( x == -1.5))  _odd = 1;
+if(_int){
+  if( _sig ==  1 && _even ) return(  0.);
+  if( _sig == -1 && _odd  ) return(  0.);
+  if( _sig ==  1 && _odd  ) return( -0.);
+  if( _sig == -1 && _even ) return( -0.);
+}
+if(_even){
+if ( x ==  0.5 ) return(R_PosInf);
+if ( x == -0.5 ) return(R_NegInf);
+}else if (_odd){
+if ( x ==  1.5 ) return(R_NegInf);
+if ( x == -1.5 ) return(R_PosInf);
+}
+// otherwise
+return tan(M_PI * x);
 }

-#if !defined(HAVE_TANPI) && defined(HAVE___TANPI)
-double tanpi(double x) {
-return __tanpi(x);
-}
 #endif




2016-12-01 18:45 GMT+09:00 Ei-ji Nakama

Re: [Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-12-01 Thread Ei-ji Nakama 
hi,

my environment...
> sessionInfo()
R version 3.3.2 (2016-10-31)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux 8 (jessie)

locale:
 [1] LC_CTYPE=ja_JP.UTF-8   LC_NUMERIC=C
 [3] LC_TIME=ja_JP.UTF-8LC_COLLATE=ja_JP.UTF-8
 [5] LC_MONETARY=ja_JP.UTF-8LC_MESSAGES=ja_JP.UTF-8
 [7] LC_PAPER=ja_JP.UTF-8   LC_NAME=C
 [9] LC_ADDRESS=C   LC_TELEPHONE=C
[11] LC_MEASUREMENT=ja_JP.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats graphics  grDevices utils datasets  methods   base

It's not a very good example...

f0<-function(x,y)exp(complex(real=x,imag=y))
f1<-function(x,y)complex(real=exp(1)^x*cos(y),imag=exp(1)^x*sin(y))
f2<-function(x,y)complex(real=exp(1)^x*cospi(y/pi),imag=exp(1)^x*sinpi(y/pi))

f0(700,1.23)
f1(700,1.23)
f2(700,1.23)

f0(700,1.23e23)
f1(700,1.23e23)
f2(700,1.23e23)

Garbage number is required.

Thank you!

2016-12-01 18:31 GMT+09:00 Prof Brian Ripley :
> Please note that you need to report your platforms (as per the posting
> guide), as the C function starts
>
> #ifdef HAVE_COSPI
> #elif defined HAVE___COSPI
> double cospi(double x) {
> return __cospi(x);
> }
>
> And AFAICS the system versions on Solaris and OS X behave the same way as
> R's substitute.
>
>
>
>
> On 01/12/2016 09:12, Martin Maechler wrote:
>>>
>>> Martin Maechler 
>>> on Thu, 1 Dec 2016 09:36:10 +0100 writes:
>>
>>
>>> Ei-ji Nakama 
>>> on Thu, 1 Dec 2016 14:39:55 +0900 writes:
>>
>>
>> >> Hi,
>> >> i try sin, cos, and tan.
>>
>> >>> sapply(c(cos,sin,tan),function(x,y)x(y),1.23e45*pi)
>> >> [1] 0.5444181 0.8388140 1.5407532
>>
>> >> However, *pi results the following
>>
>> >>> sapply(c(cospi,sinpi,tanpi),function(x,y)x(y),1.23e45)
>> >> [1] 1 0 0
>>
>> >> Please try whether the following becomes all right.
>>
>> > [..]
>>
>> > Yes, it does  -- the fix will be in all future versions of R.
>>
>> oops not so quickly, Martin!
>>
>> Of course, the results then coincide,  by sheer implementation.
>>
>> *BUT* it is not at all clear which of the two results is better;
>> e.g., if you replace '1.23' by '1' in the above examples, the
>> result of the unchnaged  *pi() functions is 100% accurate,
>> whereas
>>
>>  R> sapply(c(cos,sin,tan), function(Fn) Fn(1e45*pi))
>>  [1] -0.8847035 -0.4661541  0.5269043
>>
>> is "garbage".  After all,  1e45 is an even integer and so, the
>> (2pi)-periodic functions should give the same as for 0  which
>> *is*  (1, 0, 0).
>>
>> For such very large arguments, the results of all of sin() ,
>> cos() and tan()  are in some sense "random garbage" by
>> necessity:
>> Such large numbers have zero information about the resolution modulo
>> [0, 2pi)  or (-pi, pi]  and hence any (non-trivial) periodic
>> function with such a "small" period can only return "random noise".
>>
>>
>> > Thank you very much Ei-ji Nakama, for this valuable contribution
>> > to make R better!
>>
>> That is still true!  It raises the issue to all of us and will
>> improve the documentation at least!
>>
>> At the moment, I'm not sure where we should go.
>> Of course, I could start experiments using my own 'Rmpfr'
>> package where I can (with increasing computational effort!) get
>> correct values (for increasingly larger arguments) but at the
>> moment, I don't see how this would help.
>>
>> Martin
>
>
>
> --
> Brian D. Ripley,  rip...@stats.ox.ac.uk
> Emeritus Professor of Applied Statistics, University of Oxford



-- 
Best Regards,
--
Eiji NAKAMA 
"\u4e2d\u9593\u6804\u6cbb"  

__
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Re: [Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-12-01 Thread Prof Brian Ripley 
Please note that you need to report your platforms (as per the posting 
guide), as the C function starts


#ifdef HAVE_COSPI
#elif defined HAVE___COSPI
double cospi(double x) {
return __cospi(x);
}

And AFAICS the system versions on Solaris and OS X behave the same way 
as R's substitute.




On 01/12/2016 09:12, Martin Maechler wrote:

Martin Maechler 
on Thu, 1 Dec 2016 09:36:10 +0100 writes:



Ei-ji Nakama 
on Thu, 1 Dec 2016 14:39:55 +0900 writes:


>> Hi,
>> i try sin, cos, and tan.

>>> sapply(c(cos,sin,tan),function(x,y)x(y),1.23e45*pi)
>> [1] 0.5444181 0.8388140 1.5407532

>> However, *pi results the following

>>> sapply(c(cospi,sinpi,tanpi),function(x,y)x(y),1.23e45)
>> [1] 1 0 0

>> Please try whether the following becomes all right.

> [..]

> Yes, it does  -- the fix will be in all future versions of R.

oops not so quickly, Martin!

Of course, the results then coincide,  by sheer implementation.

*BUT* it is not at all clear which of the two results is better;
e.g., if you replace '1.23' by '1' in the above examples, the
result of the unchnaged  *pi() functions is 100% accurate,
whereas

 R> sapply(c(cos,sin,tan), function(Fn) Fn(1e45*pi))
 [1] -0.8847035 -0.4661541  0.5269043

is "garbage".  After all,  1e45 is an even integer and so, the
(2pi)-periodic functions should give the same as for 0  which
*is*  (1, 0, 0).

For such very large arguments, the results of all of sin() ,
cos() and tan()  are in some sense "random garbage" by
necessity:
Such large numbers have zero information about the resolution modulo
[0, 2pi)  or (-pi, pi]  and hence any (non-trivial) periodic
function with such a "small" period can only return "random noise".


> Thank you very much Ei-ji Nakama, for this valuable contribution
> to make R better!

That is still true!  It raises the issue to all of us and will
improve the documentation at least!

At the moment, I'm not sure where we should go.
Of course, I could start experiments using my own 'Rmpfr'
package where I can (with increasing computational effort!) get
correct values (for increasingly larger arguments) but at the
moment, I don't see how this would help.

Martin



--
Brian D. Ripley,  rip...@stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford

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Re: [Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-12-01 Thread Martin Maechler 
> Martin Maechler 
> on Thu, 1 Dec 2016 09:36:10 +0100 writes:

> Ei-ji Nakama 
> on Thu, 1 Dec 2016 14:39:55 +0900 writes:

>> Hi,
>> i try sin, cos, and tan.

>>> sapply(c(cos,sin,tan),function(x,y)x(y),1.23e45*pi)
>> [1] 0.5444181 0.8388140 1.5407532

>> However, *pi results the following

>>> sapply(c(cospi,sinpi,tanpi),function(x,y)x(y),1.23e45)
>> [1] 1 0 0

>> Please try whether the following becomes all right.

> [..]

> Yes, it does  -- the fix will be in all future versions of R.

oops not so quickly, Martin!

Of course, the results then coincide,  by sheer implementation.

*BUT* it is not at all clear which of the two results is better;
e.g., if you replace '1.23' by '1' in the above examples, the
result of the unchnaged  *pi() functions is 100% accurate,
whereas

 R> sapply(c(cos,sin,tan), function(Fn) Fn(1e45*pi))
 [1] -0.8847035 -0.4661541  0.5269043

is "garbage".  After all,  1e45 is an even integer and so, the
(2pi)-periodic functions should give the same as for 0  which
*is*  (1, 0, 0).

For such very large arguments, the results of all of sin() ,
cos() and tan()  are in some sense "random garbage" by
necessity:
Such large numbers have zero information about the resolution modulo
[0, 2pi)  or (-pi, pi]  and hence any (non-trivial) periodic
function with such a "small" period can only return "random noise".


> Thank you very much Ei-ji Nakama, for this valuable contribution
> to make R better!

That is still true!  It raises the issue to all of us and will
improve the documentation at least!

At the moment, I'm not sure where we should go.
Of course, I could start experiments using my own 'Rmpfr'
package where I can (with increasing computational effort!) get
correct values (for increasingly larger arguments) but at the
moment, I don't see how this would help.

Martin

> Martin Maechler,
> ETH Zurich


>> -- 
>> Best Regards,
>> --
>> Eiji NAKAMA 
>> "\u4e2d\u9593\u6804\u6cbb"  

> __
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

__
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Re: [Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-12-01 Thread Martin Maechler 
> Ei-ji Nakama 
> on Thu, 1 Dec 2016 14:39:55 +0900 writes:

> Hi,
> i try sin, cos, and tan.

>> sapply(c(cos,sin,tan),function(x,y)x(y),1.23e45*pi)
> [1] 0.5444181 0.8388140 1.5407532

> However, *pi results the following

>> sapply(c(cospi,sinpi,tanpi),function(x,y)x(y),1.23e45)
> [1] 1 0 0

> Please try whether the following becomes all right.

[..]

Yes, it does  -- the fix will be in all future versions of R.

Thank you very much Ei-ji Nakama, for this valuable contribution
to make R better!

Martin Maechler,
ETH Zurich


> -- 
> Best Regards,
> --
> Eiji NAKAMA 
> "\u4e2d\u9593\u6804\u6cbb"  

__
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[Rd] Different results for cos,sin,tan and cospi,sinpi,tanpi

2016-11-30 Thread Ei-ji Nakama 
Hi,

i try sin, cos, and tan.

> sapply(c(cos,sin,tan),function(x,y)x(y),1.23e45*pi)
[1] 0.5444181 0.8388140 1.5407532

However, *pi results the following

> sapply(c(cospi,sinpi,tanpi),function(x,y)x(y),1.23e45)
[1] 1 0 0

Please try whether the following becomes all right.

diff -ruN R-3.3.2.orig/src/nmath/cospi.c R-3.3.2/src/nmath/cospi.c
--- R-3.3.2.orig/src/nmath/cospi.c  2016-09-15 07:15:31.0 +0900
+++ R-3.3.2/src/nmath/cospi.c   2016-12-01 13:54:38.863357149 +0900
@@ -35,7 +35,11 @@
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

-x = fmod(fabs(x), 2.);// cos() symmetric; cos(pi(x + 2k)) ==
cos(pi x) for all integer k
+x = fabs(x);
+if ( x > 9007199254740991 ) /* 2^53-1 */
+return cos(M_PI * x);
+
+x = fmod(x, 2.);// cos() symmetric; cos(pi(x + 2k)) == cos(pi x)
for all integer k
 if(fmod(x, 1.) == 0.5) return 0.;
 if( x == 1.)   return -1.;
 if( x == 0.)   return  1.;
@@ -57,6 +61,9 @@
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

+if (( x >  9007199254740991 )||  /*  2^53-1 */
+( x < -9007199254740991 )  ) /* -2^53-1 */
+return sin(M_PI * x);
 x = fmod(x, 2.); // sin(pi(x + 2k)) == sin(pi x)  for all integer k
 // map (-2,2) --> (-1,1] :
 if(x <= -1) x += 2.; else if (x > 1.) x -= 2.;
@@ -81,6 +88,10 @@
 #endif
 if(!R_FINITE(x)) ML_ERR_return_NAN;

+if (( x >  9007199254740991 )||  /*  2^53-1 */
+( x < -9007199254740991 )  ) /* -2^53-1 */
+return tan(M_PI * x);
+
 x = fmod(x, 1.); // tan(pi(x + k)) == tan(pi x)  for all integer k
 // map (-1,1) --> (-1/2, 1/2] :
 if(x <= -0.5) x++; else if(x > 0.5) x--;

-- 
Best Regards,
--
Eiji NAKAMA 
"\u4e2d\u9593\u6804\u6cbb"  

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