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ngspice/src/ngmultidec.c

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/**********
Copyright 1990 Regents of the University of California. All rights reserved.
Author: 1990 Jaijeet Roychowdury
**********/
#include "ngspice/ngspice.h"
#include <stdio.h>
#include <math.h>
#include "ngspice/spmatrix.h"
#define THRSH 0.01
#define ABS_THRSH 0
#define DIAG_PIVOTING 1
#undef DEBUG_LEVEL1
/* `-u' option showing the usage help is changed to `-h'. -- ro */
extern void usage(char **argv);
extern void comments(double r,double l,double g,double c,double ctot,double cm,double lm,double k,char *name,int num, double len);
extern double phi(int i, double arg);
extern void spErrorMessage(MatrixPtr, FILE*, char*);
int
main (int argc, char **argv)
{
int ch;
int errflg=0,i,j;
double l,c,ctot,r=0.0,g=0.0,k=0.0,lm=0.0,cm=0.0,len;
unsigned gotl=0,gotc=0,gotr=0,gotg=0,gotk=0,gotcm=0,gotlen=0;
unsigned gotname=0, gotnum=0;
char *name = "";
double **matrix, **inverse;
double *tpeigenvalues, *gammaj;
char *options;
int num, node;
char **pname, *s;
int use_opt;
char *optarg;
pname = argv;
argv++;
argc--;
ch = 0;
while (argc > 0) {
s = *argv++;
argc--;
while ((ch = *s++) != '\0') {
if (*s)
optarg = s;
else if (argc)
optarg = *argv;
else
optarg = NULL;
use_opt = 0;
switch (ch) {
case 'o':
name = TMALLOC(char, strlen(optarg));
(void) strcpy(name,optarg);
gotname=1;
use_opt = 1;
break;
case 'l':
sscanf(optarg,"%lf",&l);
gotl=1;
use_opt = 1;
break;
case 'c':
sscanf(optarg,"%lf",&c);
gotc=1;
use_opt = 1;
break;
case 'r':
sscanf(optarg,"%lf",&r);
use_opt = 1;
gotr=1;
break;
case 'g':
sscanf(optarg,"%lf",&g);
use_opt = 1;
gotg=1;
break;
case 'k':
sscanf(optarg,"%lf",&k);
use_opt = 1;
gotk=1;
break;
case 'x':
sscanf(optarg,"%lf",&cm);
use_opt = 1;
gotcm=1;
break;
case 'L':
sscanf(optarg,"%lf",&len);
use_opt = 1;
gotlen=1;
break;
case 'n':
sscanf(optarg,"%d",&num);
use_opt = 1;
gotnum=1;
break;
case 'h':
usage(pname);
exit(1);
break;
case '-':
break;
default:
usage(pname);
exit(2);
break;
}
if (use_opt) {
if (optarg == s)
s += strlen(s);
else if (optarg) {
argc--;
argv++;
}
}
}
}
if (errflg) {
usage(argv);
exit (2);
}
if (gotl + gotc + gotname + gotnum + gotlen < 5) {
fprintf(stderr,"l, c, model_name, number_of_conductors and length must be specified.\n");
fprintf(stderr,"%s -u for details.\n",pname[0]);
fflush(stdout);
exit(1);
}
if (fabs(k) >= 1.0) {
fprintf(stderr,"Error: |k| must be less than 1.0\n");
fflush(stderr);
exit(1);
}
if (num == 1) {
fprintf(stdout,"* single conductor line\n");
fflush(stdout);
exit(1);
}
lm = l*k;
switch(num) {
case 1: ctot = c; break;
case 2: ctot = c + cm; break;
default: ctot = c + 2*cm; break;
}
comments(r,l,g,c,ctot,cm,lm,k,name,num,len);
matrix = TMALLOC(double *, num + 1);
inverse = TMALLOC(double *, num + 1);
tpeigenvalues = TMALLOC(double, num + 1);
for (i=1;i<=num;i++) {
matrix[i] = TMALLOC(double, num + 1);
inverse[i] = TMALLOC(double, num + 1);
}
for (i=1;i<=num;i++) {
tpeigenvalues[i] = -2.0 * cos(M_PI*i/(num+1));
}
for (i=1;i<=num;i++) {
for (j=1;j<=num;j++) {
matrix[i][j] = phi(i-1,tpeigenvalues[j]);
}
}
gammaj = TMALLOC(double, num + 1);
for (j=1;j<=num;j++) {
gammaj[j] = 0.0;
for (i=1;i<=num;i++) {
gammaj[j] += matrix[i][j] * matrix[i][j];
}
gammaj[j] = sqrt(gammaj[j]);
}
for (j=1;j<=num;j++) {
for (i=1;i<=num; i++) {
matrix[i][j] /= gammaj[j];
}
}
tfree(gammaj);
/* matrix = M set up */
{
MatrixPtr othermatrix;
double *rhs, *solution;
double *irhs, *isolution;
int errflg, err, singular_row, singular_col;
double *elptr;
rhs = TMALLOC(double, num + 1);
irhs = TMALLOC(double, num + 1);
solution = TMALLOC(double, num + 1);
isolution = TMALLOC(double, num + 1);
othermatrix = spCreate(num,0,&errflg);
for (i=1;i<=num;i++) {
for (j=1; j<=num; j++) {
elptr = spGetElement(othermatrix,i,j);
*elptr = matrix[i][j];
}
}
#ifdef DEBUG_LEVEL1
(void) spPrint(othermatrix,0,1,0);
#endif
for (i=1;i<=num;i++) rhs[i] = 0.0;
rhs[1]=1.0;
err =
spOrderAndFactor(othermatrix,rhs,THRSH,ABS_THRSH,DIAG_PIVOTING);
spErrorMessage(othermatrix,stderr,NULL);
switch(err) {
case spNO_MEMORY:
fprintf(stderr,"No memory in spOrderAndFactor\n");
fflush(stderr);
exit(1);
case spSINGULAR:
(void)
spWhereSingular(othermatrix,&singular_row,&singular_col);
fprintf(stderr,"Singular matrix: problem in row %d and col %d\n", singular_row, singular_col);
fflush(stderr);
exit(1);
default: break;
}
for (i=1;i<=num;i++) {
for (j=1;j<=num;j++) {
rhs[j] = (j==i?1.0:0.0);
irhs[j] = 0.0;
}
(void) spSolveTransposed(othermatrix,rhs,solution, irhs, isolution);
for (j=1;j<=num;j++) {
inverse[i][j] = solution[j];
}
}
tfree(rhs);
tfree(solution);
}
/* inverse = M^{-1} set up */
fprintf(stdout,"\n");
fprintf(stdout,"* Lossy line models\n");
options = "rel=1.2 nocontrol";
for (i=1;i<=num;i++) {
fprintf(stdout,".model mod%d_%s ltra %s r=%0.12g l=%0.12g g=%0.12g c=%0.12g len=%0.12g\n",
i,name,options,r,l+tpeigenvalues[i]*lm,g,ctot-tpeigenvalues[i]*cm,len);
/*i,name,options,r,l+tpeigenvalues[i]*lm,g,ctot+tpeigenvalues[i]*cm,len);*/
}
fprintf(stdout,"\n");
fprintf(stdout,"* subcircuit m_%s - modal transformation network for %s\n",name,name);
fprintf(stdout,".subckt m_%s", name);
for (i=1;i<= 2*num; i++) {
fprintf(stdout," %d",i);
}
fprintf(stdout,"\n");
for (j=1;j<=num;j++) fprintf(stdout,"v%d %d 0 0v\n",j,j+2*num);
for (j=1;j<=num;j++) {
for (i=1; i<=num; i++) {
fprintf(stdout,"f%d 0 %d v%d %0.12g\n",
(j-1)*num+i,num+j,i,inverse[j][i]);
}
}
node = 3*num+1;
for (j=1;j<=num;j++) {
fprintf(stdout,"e%d %d %d %d 0 %0.12g\n", (j-1)*num+1,
node, 2*num+j, num+1, matrix[j][1]);
node++;
for (i=2; i<num; i++) {
fprintf(stdout,"e%d %d %d %d 0 %0.12g\n", (j-1)*num+i,
node,node-1,num+i,matrix[j][i]);
node++;
}
fprintf(stdout,"e%d %d %d %d 0 %0.12g\n", j*num,j,node-1,
2*num,matrix[j][num]);
}
fprintf(stdout,".ends m_%s\n",name);
fprintf(stdout,"\n");
fprintf(stdout,"* Subckt %s\n", name);
fprintf(stdout,".subckt %s",name);
for (i=1;i<=2*num;i++) {
fprintf(stdout," %d",i);
}
fprintf(stdout,"\n");
fprintf(stdout,"x1");
for (i=1;i<=num;i++) fprintf(stdout," %d", i);
for (i=1;i<=num;i++) fprintf(stdout," %d", 2*num+i);
fprintf(stdout," m_%s\n",name);
for (i=1;i<=num;i++)
fprintf(stdout,"o%d %d 0 %d 0 mod%d_%s\n",i,2*num+i,3*num+i,i,name);
fprintf(stdout,"x2");
for (i=1;i<=num;i++) fprintf(stdout," %d", num+i);
for (i=1;i<=num;i++) fprintf(stdout," %d", 3*num+i);
fprintf(stdout," m_%s\n",name);
fprintf(stdout,".ends %s\n",name);
tfree(tpeigenvalues);
for (i=1;i<=num;i++) {
tfree(matrix[i]);
tfree(inverse[i]);
}
tfree(matrix);
tfree(inverse);
tfree(name);
return EXIT_NORMAL;
}
void
usage(char **argv)
{
fprintf(stderr,"Purpose: make subckt. for coupled lines using uncoupled simple lossy lines\n");
fprintf(stderr,"Usage: %s -l<line-inductance> -c<line-capacitance>\n",argv[0]);
fprintf(stderr," -r<line-resistance> -g<line-conductance> \n");
fprintf(stderr," -k<inductive coeff. of coupling> \n");
fprintf(stderr," -x<line-to-line capacitance> -o<subckt-name> \n");
fprintf(stderr," -n<number of conductors> -L<length> -h\n");
fprintf(stderr,"Example: %s -n4 -l9e-9 -c20e-12 -r5.3 -x5e-12 -k0.7 -otest -L5.4\n\n",argv[0]);
fprintf(stderr,"See \"Efficient Transient Simulation of Lossy Interconnect\",\n");
fprintf(stderr,"J.S. Roychowdhury and D.O. Pederson, Proc. DAC 91 for details\n");
fprintf(stderr,"\n");
fflush(stderr);
}
void
comments(double r,double l,double g,double c,double ctot,double cm,double lm,double k,char *name,int num, double len)
{
fprintf(stdout,"* Subcircuit %s\n",name);
fprintf(stdout,"* %s is a subcircuit that models a %d-conductor transmission line with\n",name,num);
fprintf(stdout,"* the following parameters: l=%g, c=%g, r=%g, g=%g,\n",l,c,r,g);
fprintf(stdout,"* inductive_coeff_of_coupling k=%g, inter-line capacitance cm=%g,\n",k,cm);
fprintf(stdout,"* length=%g. Derived parameters are: lm=%g, ctot=%g.\n",len,lm,ctot);
fprintf(stdout,"* \n");
fprintf(stdout,"* It is important to note that the model is a simplified one - the\n");
fprintf(stdout,"* following assumptions are made: 1. The self-inductance l, the\n");
fprintf(stdout,"* self-capacitance ctot (note: not c), the series resistance r and the\n");
fprintf(stdout,"* parallel capacitance g are the same for all lines, and 2. Each line\n");
fprintf(stdout,"* is coupled only to the two lines adjacent to it, with the same\n");
fprintf(stdout,"* coupling parameters cm and lm. The first assumption implies that edge\n");
fprintf(stdout,"* effects have to be neglected. The utility of these assumptions is\n");
fprintf(stdout,"* that they make the sL+R and sC+G matrices symmetric, tridiagonal and\n");
fprintf(stdout,"* Toeplitz, with useful consequences (see \"Efficient Transient\n");
fprintf(stdout,"* Simulation of Lossy Interconnect\", by J.S. Roychowdhury and\n");
fprintf(stdout,"* D.O Pederson, Proc. DAC 91).\n\n");
fprintf(stdout,"* It may be noted that a symmetric two-conductor line is\n");
fprintf(stdout,"* represented accurately by this model.\n\n");
fprintf(stdout,"* Subckt node convention:\n");
fprintf(stdout,"* \n");
fprintf(stdout,"* |--------------------------|\n");
fprintf(stdout,"* 1-----| |-----n+1\n");
fprintf(stdout,"* 2-----| |-----n+2\n");
fprintf(stdout,"* : | n-wire multiconductor | :\n");
fprintf(stdout,"* : | line | :\n");
fprintf(stdout,"* n-1-----|(node 0=common gnd plane) |-----2n-1\n");
fprintf(stdout,"* n-----| |-----2n\n");
fprintf(stdout,"* |--------------------------|\n\n");
fflush(stdout);
}
double
phi(int i, double arg)
{
double rval;
switch (i) {
case 0:
rval = 1.0;
break;
case 1:
rval = arg;
break;
default:
rval = arg*phi(i-1,arg) - phi(i-2,arg);
}
return rval;
}
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