/**********
Copyright 1990 Regents of the University of California.  All rights reserved.
Author: 1990 Jaijeet Roychowdury
**********/

#include "spice.h"
#include <stdio.h>
#include "strext.h"
#include <math.h>
#include "misc.h"
#include "spmatrix.h"

#define THRSH 0.01
#define ABS_THRSH 0
#define DIAG_PIVOTING	1

#undef DEBUG_LEVEL1


extern void usage();
extern void comments();
extern double phi();

 main (argc, argv)
 int argc;
 char **argv;
 {
int ch;
extern int optind, opterr;
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++;
argc--;

ch = 0;
while (argc > 0) {
  s = *argv++;
  argc--;
  while (ch = *s++) {
	if (*s)
		optarg = s;
	else if (argc)
		optarg = *argv;
	else
		optarg = NULL;
	use_opt = 0;

 switch (ch) {
 case 'o':
	 name = (char *) malloc((unsigned) (strlen(optarg)*sizeof(char)));
	 (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 'u':
	 usage(pname);
	 exit(1);
	 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",argv[0]);
fflush(stdout);
exit(1);
}

if ( (k<0.0?-k: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 = (double **) malloc((unsigned) (sizeof(double*)*(num+1)));
inverse = (double **) malloc((unsigned) (sizeof(double*)*(num+1)));
tpeigenvalues = (double *) malloc((unsigned) (sizeof(double)*(num+1)));

for (i=1;i<=num;i++) {
matrix[i] = (double *) malloc((unsigned) (sizeof(double)*(num+1)));
inverse[i] = (double *) malloc((unsigned) (sizeof(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 = (double *) malloc((unsigned) (sizeof(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];
	}
}

free(gammaj);

/* matrix = M set up */

{
char *othermatrix;
double *rhs, *solution;
double *irhs, *isolution;
int errflg, err, singular_row, singular_col;
double *elptr;

rhs = (double *) malloc((unsigned) (sizeof(double)*(num+1)));
irhs = (double *) malloc((unsigned) (sizeof(double)*(num+1)));
solution = (double *) malloc((unsigned) (sizeof(double)*(num+1)));
isolution = (double *) malloc((unsigned) (sizeof(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);
#ifdef notdef
/* For the original "sparse" interface; doesn't work with the spice3 interface
   to sparse */
case spSMALL_PIVOT:
	fprintf(stderr,"* Warning: matrix is illconditioned.\n");
	fflush(stderr);
	break;
#endif
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];
	}
}

free(rhs); free(solution);
}

/* inverse = M^{-1} set up */

fprintf(stdout,"\n");
fprintf(stdout,"* Lossy line models\n");

options = (char *) malloc((unsigned) 256);
(void) strcpy(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);

free(tpeigenvalues);
for (i=1;i<=num;i++) {
free(matrix[i]);
free(inverse[i]);
}
free(matrix);
free(inverse);
free(name);
free(options);

}

void
usage(argv)
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> -u\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(r,l,g,c,ctot,cm,lm,k,name,num,len)
double r,l,g,c,ctot,cm,lm,k,len;
char *name;
int num;
{

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(i,arg)
	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;
}
