/* This function runs the AC noise analysis. It saves its results in
the 'xn' vector. */
void acsolver::solve_noise (void) {
int N = countNodes ();
int M = countVoltageSources ();
// save usual AC results
tvector<nr_complex_t> xsave = *x;
// create the Cy matrix
createNoiseMatrix ();
// create noise result vector if necessary
if (xn == NULL) xn = new tvector<nr_double_t> (N + M);
// temporary result vector for transimpedances
tvector<nr_complex_t> zn = tvector<nr_complex_t> (N + M);
// create the MNA matrix once again and LU decompose the adjoint matrix
createMatrix ();
A->transpose ();
eqnAlgo = ALGO_LU_FACTORIZATION_CROUT;
runMNA ();
// ensure skipping LU decomposition
updateMatrix = 0;
convHelper = CONV_None;
eqnAlgo = ALGO_LU_SUBSTITUTION_CROUT;
// compute noise voltage for each node (and voltage source)
for (int i = 0; i < N + M; i++) {
z->set (0); z->set (i, -1); // modify right hand side appropriately
runMNA (); // solve
zn = *x; // save transimpedance vector
// compute actual noise voltage
xn->set (i, sqrt (real (scalar (zn * (*C), conj (zn)))));
}
// restore usual AC results
*x = xsave;
}
int nasolver<nr_type_t>::solve_once (void)
{
qucs::exception * e;
int error = 0, d;
// run the calculation function for each circuit
calculate ();
// generate A matrix and z vector
createMatrix ();
// solve equation system
try_running ()
{
runMNA ();
}
// appropriate exception handling
catch_exception ()
{
case EXCEPTION_PIVOT:
case EXCEPTION_WRONG_VOLTAGE:
e = new qucs::exception (EXCEPTION_NA_FAILED);
d = top_exception()->getData ();
pop_exception ();
if (d >= countNodes ())
{
d -= countNodes ();
e->setText ("voltage source `%s' conflicts with some other voltage "
"source", findVoltageSource(d)->getName ());
}
else
{
e->setText ("circuit admittance matrix in %s solver is singular at "
"node `%s' connected to [%s]", desc.c_str(), nlist->get (d).c_str(),
nlist->getNodeString (d).c_str());
}
throw_exception (e);
error++;
break;
case EXCEPTION_SINGULAR:
do
{
d = top_exception()->getData ();
pop_exception ();
if (d < countNodes ())
{
logprint (LOG_ERROR, "WARNING: %s: inserted virtual resistance at "
"node `%s' connected to [%s]\n", getName (), nlist->get (d).c_str(),
nlist->getNodeString (d).c_str());
}
}
while (top_exception() != NULL &&
top_exception()->getCode () == EXCEPTION_SINGULAR);
break;
default:
estack.print ();
break;
}
// save results into circuits
if (!error) saveSolution ();
return error;
}
