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/**********
Copyright 1990 Regents of the University of California. All rights reserved.
Author: 1985 Thomas L. Quarles
**********/
/* NIintegrate(ckt,geq,ceq,cap,qcap)
* integrate the specified capacitor - method and order in the
* ckt structure, ccap follows qcap.
*/
#include "ngspice/ngspice.h"
#include "ngspice/cktdefs.h"
#include "ngspice/sperror.h"
#define ccap qcap+1
int
NIintegrate(CKTcircuit *ckt, double *geq, double *ceq, double cap, int qcap)
{
static char *ordmsg = "Illegal integration order";
static char *methodmsg = "Unknown integration method";
switch(ckt->CKTintegrateMethod) {
case TRAPEZOIDAL:
switch(ckt->CKTorder) {
case 1:
ckt->CKTstate0[ccap] = ckt->CKTag[0] * ckt->CKTstate0[qcap]
+ ckt->CKTag[1] * ckt->CKTstate1[qcap];
break;
case 2:
ckt->CKTstate0[ccap] = - ckt->CKTstate1[ccap] * ckt->CKTag[1] +
ckt->CKTag[0] *
( ckt->CKTstate0[qcap] - ckt->CKTstate1[qcap] );
break;
default:
errMsg = TMALLOC(char, strlen(ordmsg) + 1);
strcpy(errMsg,ordmsg);
return(E_ORDER);
}
break;
case GEAR:
ckt->CKTstate0[ccap]=0;
switch(ckt->CKTorder) {
case 6:
ckt->CKTstate0[ccap] += ckt->CKTag[6]* ckt->CKTstate6[qcap];
/* fall through */
case 5:
ckt->CKTstate0[ccap] += ckt->CKTag[5]* ckt->CKTstate5[qcap];
/* fall through */
case 4:
ckt->CKTstate0[ccap] += ckt->CKTag[4]* ckt->CKTstate4[qcap];
/* fall through */
case 3:
ckt->CKTstate0[ccap] += ckt->CKTag[3]* ckt->CKTstate3[qcap];
/* fall through */
case 2:
ckt->CKTstate0[ccap] += ckt->CKTag[2]* ckt->CKTstate2[qcap];
/* fall through */
case 1:
ckt->CKTstate0[ccap] += ckt->CKTag[1]* ckt->CKTstate1[qcap];
ckt->CKTstate0[ccap] += ckt->CKTag[0]* ckt->CKTstate0[qcap];
break;
default:
return(E_ORDER);
}
break;
default:
errMsg = TMALLOC(char, strlen(methodmsg) + 1);
strcpy(errMsg,methodmsg);
return(E_METHOD);
}
*ceq = ckt->CKTstate0[ccap] - ckt->CKTag[0] * ckt->CKTstate0[qcap];
*geq = ckt->CKTag[0] * cap;
return(OK);
}