1 files changed, 117 insertions, 0 deletions
diff --git a/src/electronics/simulation/capacitance.cpp b/src/electronics/simulation/capacitance.cpp
new file mode 100644
index 0000000..9087c7f
--- /dev/null
+++ b/src/electronics/simulation/capacitance.cpp
@@ -0,0 +1,117 @@
+/***************************************************************************
+ *   Copyright (C) 2003-2005 by David Saxton                               *
+ *   david@bluehaze.org                                                    *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ ***************************************************************************/
+
+#include "capacitance.h"
+#include "matrix.h"
+
+Capacitance::Capacitance( const double capacitance, const double delta )
+	: Reactive(delta)
+{
+	m_cap = capacitance;
+	g_eq_old = i_eq_old = 0.;
+	m_numCNodes = 2;
+	setMethod( Capacitance::m_euler );
+}
+
+Capacitance::~Capacitance()
+{
+}
+
+void Capacitance::setCapacitance( const double c )
+{
+	m_cap = c;
+}
+
+void Capacitance::add_initial_dc()
+{
+	// We don't need to do anything here, as time_step() will do that for us,
+	// apart from to make sure our old values are 0
+	g_eq_old = i_eq_old = 0.;
+}
+
+void Capacitance::updateCurrents()
+{
+	if (!b_status) return;
+	const double r_i = (p_cnode[0]->v-p_cnode[1]->v)*g_eq_old;
+	m_cnodeI[0] = -i_eq_old-r_i;
+	m_cnodeI[1] = -m_cnodeI[0];
+}
+
+
+void Capacitance::add_map()
+{
+	if (!b_status) return;
+	
+	if ( !p_cnode[0]->isGround )
+	{
+		p_A->setUse( p_cnode[0]->n(), p_cnode[0]->n(), Map::et_unstable, false );
+	}
+	if ( !p_cnode[1]->isGround )
+	{
+		p_A->setUse( p_cnode[1]->n(), p_cnode[1]->n(), Map::et_unstable, false );
+	}
+	
+	if ( !p_cnode[0]->isGround && !p_cnode[1]->isGround )
+	{
+		p_A->setUse( p_cnode[0]->n(), p_cnode[1]->n(), Map::et_unstable, false );
+		p_A->setUse( p_cnode[1]->n(), p_cnode[0]->n(), Map::et_unstable, false );
+	}
+}
+
+
+void Capacitance::time_step()
+{
+	if (!b_status) return;
+	
+	double v = p_cnode[0]->v-p_cnode[1]->v;
+	double i_eq_new = 0.0, g_eq_new = 0.0;
+	
+	if ( m_method == Capacitance::m_euler )
+	{
+		g_eq_new = m_cap/m_delta;
+		i_eq_new = -v*g_eq_new;
+	}
+	else if ( m_method == Capacitance::m_trap ) {
+		// TODO Implement + test trapezoidal method
+		g_eq_new = 2.*m_cap/m_delta;
+	}
+	
+	if ( g_eq_old != g_eq_new )
+	{
+		A_g( 0, 0 ) += g_eq_new-g_eq_old;
+		A_g( 1, 1 ) += g_eq_new-g_eq_old;
+		A_g( 0, 1 ) -= g_eq_new-g_eq_old;
+		A_g( 1, 0 ) -= g_eq_new-g_eq_old;
+	}
+	
+	if ( i_eq_new != i_eq_old )
+	{
+		b_i( 0 ) -= i_eq_new-i_eq_old;
+		b_i( 1 ) += i_eq_new-i_eq_old;
+	}
+	
+	g_eq_old = g_eq_new;
+	i_eq_old = i_eq_new;
+}
+
+bool Capacitance::updateStatus()
+{
+	b_status = Reactive::updateStatus();
+	if ( m_method == Capacitance::m_none ) b_status = false;
+	return b_status;
+}
+
+void Capacitance::setMethod( Method m )
+{
+	m_method = m;
+	updateStatus();
+}
+
+