MapleEvalhf
evaluate an object using hardware floats in external code
EvalhfMapleProc
evaluate a procedure using hardware floats in external code
Calling Sequence
Parameters
Description
Examples
MapleEvalhf(kv, s)
EvalhfMapleProc(kv, fn, n, args)
kv
-
kernel handle of type MKernelVector
s
type ALGEB object
fn
Maple FUNCTION object
n
number of arguments
args
array of n hardware floats
These functions can be used in external code with OpenMaple or define_external.
MapleEvalhf evaluates an expression to a numerical value using the hardware floating-point of the underlying system. This command is equivalent to the Maple function, evalhf.
EvalhfMapleProc evaluates the function, f(args), to a numerical value using evalhf. The n arguments provided are all 64-bit hardware floating-point numbers. The first argument must be inserted at args[1]. For example, to call f(3.14,2.718), set args[1] = 3.14, and args[2] = 2.718. The value at args[0] is not used.
#include <math.h>
#include "maplec.h"
ALGEB M_DECL MyNewton( MKernelVector kv, ALGEB *args )
{
M_INT i;
FLOAT64 guess[2], tolerance;
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");
guess[1] = MapleEvalhf(kv,args[2]);
tolerance = MapleEvalhf(kv,args[3]);
for( i=0; i<500; ++i ) {
if( fabs(EvalhfMapleProc(kv,f,1,guess)) <= tolerance )
break;
guess[1] = guess[1] - EvalhfMapleProc(kv,f,1,guess) /
EvalhfMapleProc(kv,fprime,1,guess);
if( i == 500 ) {
MapleRaiseError(kv,"unable to find root after 500 iterations");
return( ToMapleFloat(kv,guess[1]) );
Execute the external function from Maple.
withExternalCalling:
dll≔ExternalLibraryNameHelpExamples:
newton≔DefineExternalMyNewton,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/Examples
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