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Remove unused 

Add a delay of half a time step to reduce error
This commit is contained in:
Holger Vogt 2021-06-12 16:31:11 +02:00
parent abc6eb56f3
commit 028dd0ab88
1 changed files with 11 additions and 26 deletions
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37
src/xspice/icm/analog/delay/cfunc.mod
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@ -10,7 +10,7 @@ The ngspice team
AUTHORS AUTHORS
21 May 2021 Holger Vogt 12 June 2021 Holger Vogt
MODIFICATIONS MODIFICATIONS
@ -172,7 +172,6 @@ void cm_delay(ARGS)
int buffer_size, delay_step; int buffer_size, delay_step;
double delay; double delay;
double delmin, delmax; double delmin, delmax;
double *ins, *ins_old;
mLocal_Data_t *loc; /* Pointer to local static data, not to be included mLocal_Data_t *loc; /* Pointer to local static data, not to be included
in the state vector */ in the state vector */
@ -224,14 +223,6 @@ void cm_delay(ARGS)
} }
loc->buffer_size = buffer_size; loc->buffer_size = buffer_size;
cm_analog_alloc(TRUE,sizeof(double));
ins = (double *) cm_analog_get_ptr(TRUE,0); /* Set out pointer to current
time storage */
ins_old = (double *) cm_analog_get_ptr(TRUE,1); /* Set old-output-state pointer
to previous time storage */
*ins = *ins_old = loc->start_val = INPUT(in);
/* The delay is controlled by input delay_cnt */ /* The delay is controlled by input delay_cnt */
if (PARAM(has_delay_cnt) == MIF_TRUE) { if (PARAM(has_delay_cnt) == MIF_TRUE) {
if (PARAM_NULL(delmin)) if (PARAM_NULL(delmin))
@ -276,38 +267,28 @@ void cm_delay(ARGS)
loc = STATIC_VAR (locdata); loc = STATIC_VAR (locdata);
ins = (double *) cm_analog_get_ptr(TRUE,0); /* Set out pointer to current
time storage */
ins_old = (double *) cm_analog_get_ptr(TRUE,1); /* Set old-output-state pointer
to previous time storage */
delay = loc->tdelay; delay = loc->tdelay;
if (delay == 0.0 && !PARAM(has_delay_cnt)) { if (delay == 0.0 && !PARAM(has_delay_cnt)) {
OUTPUT(out) = INPUT(in); OUTPUT(out) = INPUT(in);
return; return;
} }
if (delay < loc->tstep) {
delay = 0.;
}
if (TIME == 0.0) if (TIME == 0.0)
loc->start_val = INPUT(in); loc->start_val = INPUT(in);
/* input, simply interpolated to TSTEP */ /* input, simply interpolated to TSTEP */
double tacct = loc->step_count * loc->tstep; double tacct = loc->step_count * loc->tstep;
if (TIME >= tacct) { if (TIME >= tacct) {
double curr_in; loc->buffer[loc->buff_write] = INPUT(in);
/* double tdiff = TIME - tacct;
// interpolate
if (tdiff > 0) {
curr_in = loc->prev_val + (INPUT(in) - loc->prev_val) / (TIME - loc->tprev) * tacct;
}
else*/
curr_in = INPUT(in);
loc->buffer[loc->buff_write] = *ins = curr_in;
/* next buffer location, circular, for writing */ /* next buffer location, circular, for writing */
loc->buff_write = (loc->buff_write + 1) % loc->buffer_size; loc->buff_write = (loc->buff_write + 1) % loc->buffer_size;
loc->step_count++; loc->step_count++;
loc->tprev = tacct; loc->tprev = tacct;
loc->prev_val = curr_in; loc->prev_val = INPUT(in);
} }
delmin = loc->tdelmin; delmin = loc->tdelmin;
@ -326,6 +307,10 @@ void cm_delay(ARGS)
else else
OUTPUT(out) = loc->buffer[loc->buff_del]; OUTPUT(out) = loc->buffer[loc->buff_del];
/* add offset to reduce error */
/* FIXME: may not be needed if (better) interpolation */
delay += 0.5 * loc->tstep;
/* delay in steps */ /* delay in steps */
delay_step = (int)(delay / loc->tstep); delay_step = (int)(delay / loc->tstep);
/* FIXME: For whatever reason the model is assessed two times per time step */ /* FIXME: For whatever reason the model is assessed two times per time step */