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Restrict the limit for exp function (linear growth when exponent 

is larger than 14, commit [93a76d]) to the PSPICE compatibility
mode.
This commit is contained in:
Holger Vogt 2021-04-09 10:56:04 +02:00
parent 8da2f3c16d
commit e2cf397b6d
2 changed files with 14 additions and 7 deletions
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16
src/spicelib/parser/inpptree.c
View File

@ -5,6 +5,7 @@ Author: 1987 Wayne A. Christopher, U. C. Berkeley CAD Group
//#define TRACE
#include "ngspice/ngspice.h"
#include "ngspice/compatmode.h"
#include "ngspice/ifsim.h"
#include "ngspice/iferrmsg.h"
#include "ngspice/inpdefs.h"
@ -448,11 +449,16 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
break;
case PTF_EXP: /* u > EXPARGMAX -> EXPMAX, that is exp(EXPARGMAX), else exp(u) */
arg1 = mkb(PT_TERN,
mkf(PTF_GT0, mkb(PT_MINUS, p->left, mkcon(EXPARGMAX))),
mkb(PT_COMMA,
mkcon(EXPMAX),
mkf(PTF_EXP, p->left)));
if (newcompat.ps) {
arg1 = mkb(PT_TERN,
mkf(PTF_GT0, mkb(PT_MINUS, p->left, mkcon(EXPARGMAX))),
mkb(PT_COMMA,
mkcon(EXPMAX),
mkf(PTF_EXP, p->left)));
}
else { /* exp(u) */
arg1 = mkf(PTF_EXP, p->left);
}
#ifdef TRACE1
printf("debug exp, %s, returns; ", __func__);

5
src/spicelib/parser/ptfuncs.c
View File

@ -215,11 +215,12 @@ PTcosh(double arg)
return (cosh(arg));
}
/* Limit the exp: If arg > EXPARGMAX (arbitrarily selected to 14), continue with linear output */
/* Limit the exp: If arg > EXPARGMAX (arbitrarily selected to 14), continue with linear output,
if compatmode PSPICE is selected*/
double
PTexp(double arg)
{
if (arg > EXPARGMAX)
if (newcompat.ps && arg > EXPARGMAX)
return EXPMAX * (arg - EXPARGMAX + 1.);
else
return (exp(arg));