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XBLite Forum / XBLite Programming / LONGDOUBLE functions
Posted by: sospel, August 21, 2008, 3:51pm
Hello !
Continuing my tests of XBLite, I need mathematical functions for numbers of type " LONGDOUBLE ".
I' ve found all the functions which I need in " XbLite\Programme\xblite\demo\longdouble \xml " ...
except two : the fontion ATANL (inverse of "TANL"), and "EXPL"
I am going to try to write it in ASSEMBLER language , but as I know ~ nothing in this language, I would
be happy if one of you has a reference, a link or a Web site where I could find these 2 functions for
XBLite!!
Thank you in advance for any answer!
Cordially,
Sospel
Posted by: 26 (Guest), August 22, 2008, 9:02am; Reply: 1
For AtanL, this one seems to work correctly :
Quoted Text
DECLARE FUNCTION LONGDOUBLE AtanL (LONGDOUBLE xld)
Quoted Text
'
' ###################
' ##### AtanL #####
' ###################
'
FUNCTION LONGDOUBLE AtanL (LONGDOUBLE xld)
LONGDOUBLE ln
ASM fld t[ebp+8] ;get param on stack
ASM fld1 ;ST(0)=1.0,ST(1)=param
ASM fpatan ;compute atan(ST(1)),divide by ST(0) and pop ST(0) so ST(0)=atan(rad)
ASM fstp t[ebp-32] ;write result on ln
RETURN ln
END FUNCTION
Finally found a bit of time and adapted exp from :
http://www.jbox.dk/sanos/source/lib/math/exp.asm.html (no pain, first match w/ google ;) )
Quoted Text
DECLARE FUNCTION LONGDOUBLE ExpL (LONGDOUBLE xld)
Quoted Text
'
' ##################
' ##### ExpL #####
' ##################
'
FUNCTION LONGDOUBLE ExpL (LONGDOUBLE xld)
LONGDOUBLE ln
ASM fld t[ebp+8] ;get param on stack
ASM fldl2e ; Load log base 2(e)
ASM fmulp st1,st0 ; Multiply x * log base 2(e)
ASM fst st1 ; Push result
ASM frndint ; Round to integer
ASM fsub st1,st0 ; Subtract
ASM fxch ; Exchange st, st(1)
ASM f2xm1 ; Compute 2 to the (x - 1)
ASM fld1 ; Load real number 1
ASM fadd ; 2 to the x
ASM fscale ; Scale by power of 2
ASM fstp st1 ; Set new stack top and pop
ASM fstp t[ebp-32] ;write result on ln
RETURN ln
END FUNCTION
Tested theses funcs quickly but they seem to give correct result.
Posted by: 26 (Guest), August 22, 2008, 9:26am; Reply: 2
Posted by: 17 (Guest), August 22, 2008, 10:10am; Reply: 3
Hi Fano,
So cool! Thanks.
Bye! Guy
Posted by: sospel, August 22, 2008, 12:23pm; Reply: 4
Hello FANO !
"longdouble" thanks for your answer : I' ll try these functions to make a test with some functions and their
inverse. Afterwards, I will send results :))
Cordially,
SosPel
Posted by: sospel, August 28, 2008, 3:02pm; Reply: 5
Hello !
I continued the test with the functions to study " LONGDOUBLE " variables . The results are bad!
Here is the test:
I use a benchmark the formulation of which is this one:
value = 1.0
FOR i=1 TO 10
FOR j=1 TO 1000
FOR k=1 TO 1000
value = Tan(Atan(Exp(Log(Sqrt(value * value)))))+1.0
NEXT k
NEXT j
NEXT i
PRINT "value "; STRING$(value)
error=(1.0 - value/1.e7) * 100.0
PRINT "error "; STRING$(error)
( Benchmark take in an old "Sky & Telescope" review)
I adapt these instructions according to the used language (ex: in XBLite, I put all the useful functions in
assembler - see precedents posts). All the calculations are made in "DOUBLE PRECISION". Results :
1/in FORTRAN 95 : value = 10000001.000593 , error in % = 0.000010005 [Reference calculation]
2/in GFA-Basic (WinXP) : value = 10000001.001222 , error in % = 0.000010001 [remarkable for a "BASIC"!!]
3/in Visual-Basic 6 : value = 9999818.448501 , error in % = 0.001815515 [acceptable]
4/in Emergence BASIC : value = 9999818.448501 , error in % = 0.001815515 [NB: idem than VB6].
5/in XBLite D.P : value = 9999818.448501 , error in % = 0.001815515 [NB: idem than VB6].
But on opposite, the XBLite calculation in LONGDOUBLE is false :
6/in XBLite ( LD.P): value = 2.484822
(maybe I made an error of programming?)
Temporary conclusion: it would be doubtless interesting that somebody bends over these functions in LD,
to bring XBLite at the level of precision of the GFA ???
Cordially
SosPel
Posted by: 26 (Guest), August 28, 2008, 6:16pm; Reply: 6
I took 5 mins to look if LDP functions were giving coherents result compared to DP and i noticed a difference between Log and LogL so i edited function and attached xml2.x.As before i found asm funcs there :
http://www.jbox.dk/sanos/source/lib/math/ (BSD license)
[fanboy mode]
Prepares to place XBlite 1st :P
[/fanboy mode]
Posted by: XBLiteAdmin, August 30, 2008, 11:17pm; Reply: 7
Hello !
I continued the test with the functions to study " LONGDOUBLE " variables . The results are bad!
Here is the test:
I use a benchmark the formulation of which is this one:
value = 1.0
FOR i=1 TO 10
FOR j=1 TO 1000
FOR k=1 TO 1000
value = Tan(Atan(Exp(Log(Sqrt(value * value)))))+1.0
NEXT k
NEXT j
NEXT i
PRINT "value "; STRING$(value)
error=(1.0 - value/1.e7) * 100.0
PRINT "error "; STRING$(error)
( Benchmark take in an old "Sky & Telescope" review)
I adapt these instructions according to the used language (ex: in XBLite, I put all the useful functions in
assembler - see precedents posts). All the calculations are made in "DOUBLE PRECISION". Results :
1/in FORTRAN 95 : value = 10000001.000593 , error in % = 0.000010005 [Reference calculation]
2/in GFA-Basic (WinXP) : value = 10000001.001222 , error in % = 0.000010001 [remarkable for a "BASIC"!!]
3/in Visual-Basic 6 : value = 9999818.448501 , error in % = 0.001815515 [acceptable]
4/in Emergence BASIC : value = 9999818.448501 , error in % = 0.001815515 [NB: idem than VB6].
5/in XBLite D.P : value = 9999818.448501 , error in % = 0.001815515 [NB: idem than VB6].
But on opposite, the XBLite calculation in LONGDOUBLE is false :
6/in XBLite ( LD.P): value = 2.484822
(maybe I made an error of programming?)
Temporary conclusion: it would be doubtless interesting that somebody bends over these functions in LD,
to bring XBLite at the level of precision of the GFA ???
Cordially
SosPel
Hi,
I believe the trouble is just with the naming convention used in the xml library. The LogL function should really be named Log10L, and the LnL should be LogL. So for your test above, use LnL instead of LogL.
When using the correct functions, I got the folowing results from the benchmark:
value 1.000000100111374133d+7
error -1.001113741329546017d-5
I will correct the functions names in xml so they correspond correctly with the xma functions.
ciao,
D.
Posted by: sospel, September 1, 2008, 8:06pm; Reply: 8
Hello !
Thanks to D. Administrator : I' ve changed LnL in formula and now, I have same excellent results.
Well, Xblite is as well good as GFA !!
Now, I go to another programs ...
Cordially,
SosPel
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