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/* $Id$ */
/*.......1.........2.........3.........4.........5.........6.........7.........8
================================================================================
FILE hyst/cfunc.mod
Copyright 1991
Georgia Tech Research Corporation, Atlanta, Ga. 30332
All Rights Reserved
PROJECT A-8503-405
AUTHORS
6 Jun 1991 Jeffrey P. Murray
MODIFICATIONS
2 Oct 1991 Jeffrey P. Murray
SUMMARY
This file contains the model-specific routines used to
functionally describe the hyst code model.
INTERFACES
FILE ROUTINE CALLED
CMutil.c void cm_smooth_corner();
CM.c void *cm_analog_alloc()
void *cm_analog_get_ptr()
REFERENCED FILES
Inputs from and outputs to ARGS structure.
NON-STANDARD FEATURES
NONE
===============================================================================*/
/*=== INCLUDE FILES ====================*/
#include "cm_hyst.h"
/*=== CONSTANTS ========================*/
/*=== MACROS ===========================*/
/*=== LOCAL VARIABLES & TYPEDEFS =======*/
/*=== FUNCTION PROTOTYPE DEFINITIONS ===*/
/*==============================================================================
FUNCTION void hyst()
AUTHORS
2 Oct 1991 Jeffrey P. Murray
MODIFICATIONS
NONE
SUMMARY
This function implements the hyst code model.
INTERFACES
FILE ROUTINE CALLED
CMutil.c void cm_smooth_corner();
CM.c void *cm_analog_alloc()
void *cm_analog_get_ptr()
RETURNED VALUE
Returns inputs and outputs via ARGS structure.
GLOBAL VARIABLES
NONE
NON-STANDARD FEATURES
NONE
==============================================================================*/
/*=== CM_HYST ROUTINE ===*/
/*************************************************************************
* BEHAVIOR OF HYSTERESIS: *
* out hyst hyst *
* ^ ____/\_____ ____/\_____ *
* | / \/ \ *
* | x_fall_linear x_rise_zero *
* out_upper_limit- - *----<-------------<------*-------> *
* | /| /| /| *
* | / /in_high / *
* | / | / | / | *
* | / / __/ *
* | |/_ | / | /| | *
* | / / / *
* | / | / | / | *
* <------O----/------------/------------/-----------------------> in *
* | | / | / | / *
* | / / / *
* <--------*------->----|---->-------* - - - - out_lower_limit *
* x_fall_zero in_low x_rise_linear *
* V *
* *
* input_domain defines "in" increment below & above the "*" points *
* shown, within which smoothing of the d(out)/d(in) values *
* occurs...this prevents abrupt changes in d(out)/d(in) which *
* could prevent the simulator from reaching convergence during *
* a transient or DC analysis. *
* *
**************************************************************************/
/**************************************************************************/
/* Usage of cm_smooth_corner: */
/* */
/* void cm_smooth_corner(double x_input, double x_center, double y_center, */
/* double domain, double lower_slope, */
/* double upper_slope,double *y_output, double *dy_dx) */
/* */
/**************************************************************************/
void cm_hyst(ARGS) /* structure holding parms,
inputs, outputs, etc. */
{
double in, /* input to hysteresis block */
out, /* output from hysteresis block */
in_low, /* lower input value for hyst=0 at which
the transfer curve changes from constant
to linear */
in_high, /* upper input value for hyst=0 at which
the transfer curve changes from constant
to linear */
hyst, /* the hysteresis value (see above diagram) */
out_lower_limit, /* the minimum output value from the block */
out_upper_limit, /* the maximum output value from the block */
input_domain, /* the delta value of the input above and
below in_low and in_high within which
smoothing will be applied to the output
in order to maintain continuous first partial
derivatives. */
slope, /* calculated rise and fall slope for the block */
pout_pin, /* partial derivative of output w.r.t. input */
x_rise_linear, /* = in_low + hyst */
x_rise_zero, /* = in_high + hyst */
x_fall_linear, /* = in_high - hyst */
x_fall_zero; /* = in_low - hyst */
Boolean_t *hyst_state, /* TRUE => input is on lower leg of
hysteresis curve, between -infinity
and in_high + hyst.
FALSE => input is on upper leg
of hysteresis curve, between
in_low - hyst and +infinity */
*old_hyst_state; /* previous value of *hyst_state */
Mif_Complex_t ac_gain; /* AC gain */
/** Retrieve frequently used parameters... **/
in_low = PARAM(in_low);
in_high = PARAM(in_high);
hyst = PARAM(hyst);
out_lower_limit = PARAM(out_lower_limit);
out_upper_limit = PARAM(out_upper_limit);
input_domain = PARAM(input_domain);
/** Calculate Hysteresis Linear Region Slopes & Derived Values **/
/* Define slope of rise and fall lines when not being smoothed */
slope = (out_upper_limit - out_lower_limit)/(in_high - in_low);
x_rise_linear = in_low + hyst; /* Breakpoint - x rising to
linear region */
x_rise_zero = in_high + hyst; /* Breakpoint - x rising to
zero-slope (out_upper_limit) */
x_fall_linear = in_high - hyst; /* Breakpoint - x falling to
linear region */
x_fall_zero = in_low - hyst; /* Breakpoint - x falling to
zero-slope (out_lower_limit) */
if (PARAM(fraction) == MIF_TRUE) /* Set range to absolute value */
input_domain = input_domain * (in_high - in_low);
/** Retrieve frequently used inputs... **/
in = INPUT(in);
/** Test for INIT; if so, allocate storage, otherwise, retrieve
previous timepoint value for output... **/
if (INIT==1) { /* First pass...allocate storage for previous state. */
/* Also, calculate roughly where the current output */
/* will be and use this value to define current state. */
hyst_state = cm_analog_alloc(TRUE,sizeof(Boolean_t));
old_hyst_state = cm_analog_get_ptr(TRUE,1);
if (in < x_rise_zero + input_domain) { /* Set state to X_RISING */
*old_hyst_state = X_RISING;
}
else {
*old_hyst_state = X_FALLING;
}
}
else { /* Allocation not necessary...retrieve previous values */
hyst_state = cm_analog_get_ptr(TRUE,0); /* Set out pointer to current
time storage */
old_hyst_state = cm_analog_get_ptr(TRUE,1); /* Set old-output-state pointer
to previous time storage */
}
/** Set *hyst_out = *old_hyst_out, unless changed below...
we don't need the last iteration value of *hyst_state. **/
*hyst_state = *old_hyst_state;
/*** Calculate value of hyst_state, pout_pin.... ***/
if (*old_hyst_state == X_RISING) { /* Assume calculations on lower */
/* hysteresis section (x rising) */
if ( in <= x_rise_linear - input_domain ) { /* Output @ lower limit */
out = out_lower_limit;
pout_pin = 0.0;
}
else {
if ( in <= x_rise_linear + input_domain ) { /* lower smoothing region */
cm_smooth_corner(in,x_rise_linear,out_lower_limit,input_domain,
0.0,slope,&out,&pout_pin);
}
else {
if (in <= x_rise_zero - input_domain) { /* Rising linear region */
out = (in - x_rise_linear)*slope + out_lower_limit;
pout_pin = slope;
}
else {
if (in <= x_rise_zero + input_domain) { /* Upper smoothing region */
cm_smooth_corner(in,x_rise_zero,out_upper_limit,input_domain,
slope,0.0,&out,&pout_pin);
}
else { /* input has transitioned to X_FALLING region... */
out = out_upper_limit;
pout_pin = 0.0;
*hyst_state = X_FALLING;
}
}
}
}
}
else { /* Assume calculations on upper hysteresis section (x falling) */
if ( in >= x_fall_linear + input_domain ) { /* Output @ upper limit */
out = out_upper_limit;
pout_pin = 0.0;
}
else {
if ( in >= x_fall_linear - input_domain ) { /* Upper smoothing region */
cm_smooth_corner(in,x_fall_linear,out_upper_limit,input_domain,
slope,0.0,&out,&pout_pin);
}
else {
if (in >= x_fall_zero + input_domain) { /* Falling linear region */
out = (in - x_fall_zero)*slope + out_lower_limit;
pout_pin = slope;
}
else {
if (in >= x_fall_zero - input_domain) { /* Lower smoothing region */
cm_smooth_corner(in,x_fall_zero,out_lower_limit,input_domain,
0.0,slope,&out,&pout_pin);
}
else { /* input has transitioned to X_RISING region... */
out = out_lower_limit;
pout_pin = 0.0;
*hyst_state = X_RISING;
}
}
}
}
}
if (ANALYSIS != MIF_AC) { /* DC & Transient Analyses */
OUTPUT(out) = out;
PARTIAL(out,in) = pout_pin;
}
else { /* AC Analysis */
ac_gain.real = pout_pin;
ac_gain.imag= 0.0;
AC_GAIN(out,in) = ac_gain;
}
}