MapleTohfData
initialize hfdata structures for use in external code
Calling Sequence
Parameters
Description
Examples
MapleTohfData(kv, a, hf)
DoubleTohfData(kv, re, im, hf)
ComplexTohfData(kv, re, im, hf)
kv
-
kernel handle of type MKernelVector
a
Maple PROC or RTABLE object
re
the value to use as the real component
im
the value to use as the imaginary component
hf
a pointer to the hfdata structure to initialize
These functions can be used in external code with OpenMaple or define_external.
MapleTohfData encodes a Maple PROC or an RTABLE of type float[8] into an hfdata structure. These structures are used to pass arguments into and get results out of EvalhfDataProc.
DoubleTohfData and ComplexTohfData encode a complex number represented as two doubles into an hfdata structure. They differ in that if the im argument to DoubleTohfData is 0.0 or -0.0 it will be ignored, so the resulting hf structure will be treated as representing a real number, not a real number with zero imaginary part. These structures are used to pass arguments into and get results out of EvalhfDataProc.
A Maple object encoded in a hfdata structure can be extracted by calling ToMaplehfData. The real and imaginary parts of a hfdata can be extracted by calling RealhfData and ImaginaryhfData.
All hfdata objects returned by EvalhfDataProc represent real floating point values.
#include <math.h>
#include "maplec.h"
ALGEB MyNewtonData( MKernelVector kv, ALGEB *args )
{
M_INT i;
FLOAT64 tolerance, newguess, res;
hfdata guess[2];
ALGEB f, fprime, x;
if( 3 != MapleNumArgs(kv,(ALGEB)args) ) {
MapleRaiseError(kv,"three arguments expected");
return( NULL );
}
if( IsMapleProcedure(kv,args[1]) ) {
f = args[1];
else {
ALGEB indets;
indets = EvalMapleProc(kv,ToMapleName(kv,"indets",TRUE),1,args[1]);
if( !IsMapleSet(kv,indets) || MapleNumArgs(kv,indets) != 1 ) {
MapleRaiseError(kv,"unable to find roots");
i = 1;
f = EvalMapleProc(kv,ToMapleName(kv,"unapply",TRUE),2,args[1],
MapleSelectIndexed(kv,indets,1,&i));
if( !f || !IsMapleProcedure(kv,f) ) {
MapleRaiseError(kv,"unable to convert first arg to a procedure");
x = ToMapleName(kv,"x",FALSE);
fprime = EvalMapleProc(kv,ToMapleName(kv,"unapply",TRUE),2,
EvalMapleProc(kv,ToMapleName(kv,"diff",TRUE),2,
ToMapleFunction(kv,f,1,x),x),x);
if( !fprime || !IsMapleProcedure(kv,fprime) ) {
MapleRaiseError(kv,"unable to compute derivative");
DoubleTohfData( kv, MapleEvalhf( kv, args[2] ), 0, guess+1 );
tolerance = MapleEvalhf(kv,args[3]);
res = 0.0;
for( i=0; i<500; ++i ) {
res = RealhfData( kv, EvalhfDataProc(kv,f,1,guess) );
if( fabs( res ) <= tolerance )
break;
newguess = RealhfData( kv, guess[1] ) -
res / RealhfData( kv, EvalhfDataProc(kv,fprime,1,guess) );
DoubleTohfData( kv, newguess, 0, guess+1 );
if( i == 500 ) {
MapleRaiseError(kv,"unable to find root after 500 iterations");
return( ToMapleFloat(kv, RealhfData( kv, guess[1] ) ) );
Execute the external function from Maple.
withExternalCalling:
dll≔ExternalLibraryNameHelpExamples:
newton≔DefineExternalMyNewtonData,dll:
f≔x4−5x2+6x−2:
newtonf,0,0.001
0.731892751250226237
evalf,x=
−0.000039355
newtonf,sqrt2,0.00001
1.00195003210012135
3.833×10−6
newtonf,−π,1.×10−10
−2.73205080756887719
Digits≔15:
1.5×10−13
f≔unapplyf,x:
evalhff
−7.10542735760100186×10−15
See Also
CustomWrapper
define_external
evalhf
OpenMaple
OpenMaple/C/API
OpenMaple/C/EvalhfDataProc
OpenMaple/C/Examples
OpenMaple/C/ImaginaryhfData
OpenMaple/C/RealhfData
OpenMaple/C/ToMaplehfData
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