netlist_time compute_next_timestep(double cur_ts)
{
nl_double new_solver_timestep = m_params.m_max_timestep;
if (m_params.m_dynamic_ts)
{
for (int k = 0, iN = m_terms.size(); k < iN; k++)
{
analog_net_t n = m_nets[k];
terms_for_net_t t = m_terms[k].get();
nl_double DD_n = (n.Q_Analog() - t.last_V);
nl_double hn = cur_ts;
//printf("%f %f %f %f\n", DD_n, t->m_DD_n_m_1, hn, t->m_h_n_m_1);
nl_double DD2 = (DD_n / hn - t.DD_n_m_1 / t.h_n_m_1) / (hn + t.h_n_m_1);
nl_double new_net_timestep;
t.h_n_m_1 = hn;
t.DD_n_m_1 = DD_n;
if (Math.Abs(DD2) > nl_config_global.NL_FCONST(1e-60)) // avoid div-by-zero
{
new_net_timestep = Math.Sqrt(m_params.m_dynamic_lte / Math.Abs(nl_config_global.NL_FCONST(0.5) * DD2));
}
else
{
new_net_timestep = m_params.m_max_timestep;
}
if (new_net_timestep < new_solver_timestep)
{
new_solver_timestep = new_net_timestep;
}
t.last_V = n.Q_Analog();
}
if (new_solver_timestep < m_params.m_min_timestep)
{
//log().warning("Dynamic timestep below min timestep. Consider decreasing MIN_TIMESTEP: {1} us", new_solver_timestep*1.0e6);
new_solver_timestep = m_params.m_min_timestep;
}
}
//if (new_solver_timestep > 10.0 * hn)
// new_solver_timestep = 10.0 * hn;
/*
* FIXME: Factor 2 below is important. Without, we get timing issues. This must be a bug elsewhere.
*/
return(netlist_time.Max(netlist_time.from_double(new_solver_timestep), netlist_time.quantum() * 2));
}
//template <typename T>
//void store(const T * RESTRICT V);
//template <typename T>
//T delta(const T * RESTRICT V);
//template <typename T>
//void build_LE_A();
//template <typename T>
//void build_LE_RHS();
/* calculate matrix */
void setup_matrix()
{
UInt32 iN = (UInt32)m_nets.size();
for (UInt32 k = 0; k < iN; k++)
{
m_terms[k].railstart = m_terms[k].count();
for (UInt32 i = 0; i < m_rails_temp[k].count(); i++)
{
this.m_terms[k].add(m_rails_temp[k].terms()[i], m_rails_temp[k].connected_net_idx()[i], false);
}
m_terms[k].set_pointers();
}
foreach (terms_for_net_t rt in m_rails_temp)
{
rt.clear(); // no longer needed
//plib::pfree(rt); // no longer needed
}
m_rails_temp.clear();
/* Sort in descending order by number of connected matrix voltages.
* The idea is, that for Gauss-Seidel algo the first voltage computed
* depends on the greatest number of previous voltages thus taking into
* account the maximum amout of information.
*
* This actually improves performance on popeye slightly. Average
* GS computations reduce from 2.509 to 2.370
*
* Smallest to largest : 2.613
* Unsorted : 2.509
* Largest to smallest : 2.370
*
* Sorting as a general matrix pre-conditioning is mentioned in
* literature but I have found no articles about Gauss Seidel.
*
* For Gaussian Elimination however increasing order is better suited.
* NOTE: Even better would be to sort on elements right of the matrix diagonal.
*
*/
if (m_sort != eSortType.NOSORT)
{
int sort_order = (m_sort == eSortType.DESCENDING ? 1 : -1);
for (UInt32 k = 0; k < iN - 1; k++)
{
for (UInt32 i = k + 1; i < iN; i++)
{
if (((int)(m_terms[k].railstart) - (int)(m_terms[i].railstart)) * sort_order < 0)
{
//std::swap(m_terms[i], m_terms[k]);
var termsTemp = m_terms[i];
m_terms[i] = m_terms[k];
m_terms[k] = termsTemp;
//std::swap(m_nets[i], m_nets[k]);
var netsTemp = m_nets[i];
m_nets[i] = m_nets[k];
m_nets[k] = netsTemp;
}
}
}
foreach (var term in m_terms)
{
var other = term.connected_net_idx();
for (UInt32 i = 0; i < term.count(); i++)
{
if (other[i] != -1)
{
other[i] = get_net_idx(term.terms()[i].otherterm.net());
}
}
}
}
/* create a list of non zero elements. */
for (UInt32 k = 0; k < iN; k++)
{
terms_for_net_t t = m_terms[k];
/* pretty brutal */
var other = t.connected_net_idx();
t.nz.clear();
for (UInt32 i = 0; i < t.railstart; i++)
{
if (!t.nz.Contains((UInt32)other[i])) //if (!plib::container::contains(t->m_nz, static_cast<unsigned>(other[i])))
{
t.nz.push_back((UInt32)other[i]);
}
}
t.nz.push_back(k); // add diagonal
/* and sort */
t.nz.Sort(); //std::sort(t.m_nz.begin(), t.m_nz.end());
}
/* create a list of non zero elements right of the diagonal
* These list anticipate the population of array elements by
* Gaussian elimination.
*/
for (UInt32 k = 0; k < iN; k++)
{
terms_for_net_t t = m_terms[k];
/* pretty brutal */
var other = t.connected_net_idx();
if (k == 0)
{
t.nzrd.clear();
}
else
{
t.nzrd = m_terms[k - 1].nzrd;
for (var jIdx = 0; jIdx < t.nzrd.Count;) //for (var j = t.nzrd.begin(); j != t.nzrd.end(); )
{
var j = t.nzrd[jIdx];
if (j < k + 1)
{
t.nzrd.erase(jIdx);
}
else
{
++jIdx;
}
}
}
for (UInt32 i = 0; i < t.railstart; i++)
{
if (!t.nzrd.Contains((UInt32)other[i]) && other[i] >= (int)(k + 1)) //if (!plib::container::contains(t->m_nzrd, static_cast<unsigned>(other[i])) && other[i] >= static_cast<int>(k + 1))
{
t.nzrd.push_back((UInt32)other[i]);
}
}
/* and sort */
t.nzrd.Sort(); //std::sort(t.m_nzrd.begin(), t.m_nzrd.end());
}
/* create a list of non zero elements below diagonal k
* This should reduce cache misses ...
*/
bool [,] touched = new bool [iN, iN]; //bool **touched = plib::palloc_array<bool *>(iN);
//for (UInt32 k = 0; k < iN; k++)
// touched[k] = plib::palloc_array<bool>(iN);
for (UInt32 k = 0; k < iN; k++)
{
for (UInt32 j = 0; j < iN; j++)
{
touched[k, j] = false;
}
for (UInt32 j = 0; j < m_terms[k].nz.size(); j++)
{
touched[k, m_terms[k].nz[j]] = true;
}
}
m_ops = 0;
for (UInt32 k = 0; k < iN; k++)
{
m_ops++; // 1/A(k,k)
for (UInt32 row = k + 1; row < iN; row++)
{
if (touched[row, k])
{
m_ops++;
if (!m_terms[k].nzbd.Contains(row)) //if (!plib::container::contains(m_terms[k]->m_nzbd, row))
{
m_terms[k].nzbd.push_back(row);
}
for (UInt32 col = k + 1; col < iN; col++)
{
if (touched[k, col])
{
touched[row, col] = true;
m_ops += 2;
}
}
}
}
}
log().verbose.op("Number of mults/adds for {0}: {1}", name(), m_ops);
#if false
if ((0))
{
for (unsigned k = 0; k < iN; k++)
{
pstring line = plib::pfmt("{1:3}")(k);
for (unsigned j = 0; j < m_terms[k]->m_nzrd.size(); j++)
{
line += plib::pfmt(" {1:3}")(m_terms[k]->m_nzrd[j]);
}
log().verbose("{1}", line);
}
}
#endif
/*
* save states
*/
for (UInt32 k = 0; k < iN; k++)
{
string num = new plib.pfmt("{0}").op(k);
state().save(this, m_terms[k].last_V, "lastV." + num);
state().save(this, m_terms[k].DD_n_m_1, "m_DD_n_m_1." + num);
state().save(this, m_terms[k].h_n_m_1, "m_h_n_m_1." + num);
state().save(this, m_terms[k].go(), "GO" + num, m_terms[k].count());
state().save(this, m_terms[k].gt(), "GT" + num, m_terms[k].count());
state().save(this, m_terms[k].Idr(), "IDR" + num, m_terms[k].count());
}
//for (UInt32 k = 0; k < iN; k++)
// plib::pfree_array(touched[k]);
//plib::pfree_array(touched);
touched = null;
}