cfunc.mod

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/* $Id: cfunc.mod,v 1.3 2004/07/09 18:37:57 pnenzi Exp $ */
/*.......1.........2.........3.........4.........5.........6.........7.........8
================================================================================

FILE pwl/cfunc.mod

Copyright 1991
Georgia Tech Research Corporation, Atlanta, Ga. 30332
All Rights Reserved

PROJECT A-8503-405
               

AUTHORS                      

    19 Apr 1991     Jeffrey P. Murray


MODIFICATIONS   

    25 Sep 1991    Jeffrey P. Murray
     2 Oct 1991    Jeffrey P. Murray
                                   

SUMMARY

    This file contains the model-specific routines used to
    functionally describe the pwl (piece-wise linear) code model.


INTERFACES       

    FILE                 ROUTINE CALLED     

    CMutil.c             void cm_smooth_corner(); 

    CMmacros.h           cm_message_send();                   
                             
    CM.c                 void cm_analog_not_converged()


REFERENCED FILES

    Inputs from and outputs to ARGS structure.
                     

NON-STANDARD FEATURES

    NONE

===============================================================================*/

/*=== INCLUDE FILES ====================*/

#include <math.h>

                                      

/*=== CONSTANTS ========================*/

#define FRACTION 0.30
#define EPSILON 1.0e-9



/*=== MACROS ===========================*/



  
/*=== LOCAL VARIABLES & TYPEDEFS =======*/                         


    
           
/*=== FUNCTION PROTOTYPE DEFINITIONS ===*/




                   
/*==============================================================================

FUNCTION double limit_x_value()

AUTHORS                      

    25 Sep 1991     Jeffrey P. Murray


MODIFICATIONS   

     2 Oct 1991    Jeffrey P. Murray

SUMMARY

    Limits a passed input value to some fraction       
    of the segment length defined by                   
    (x_upper - x_lower). The fractional value in       
    question is passed as a value to the routine       
    (fraction).                                        
                                                       

INTERFACES       

    FILE                 ROUTINE CALLED     

    CM.c                 void cm_analog_not_converged()


RETURNED VALUE
    
    Returns a double.

GLOBAL VARIABLES
    
    NONE

NON-STANDARD FEATURES

    NONE

==============================================================================*/

#include <stdlib.h>

/*=== Static LIMIT_X_VALUE ROUTINE ================*/
                                         
/** limit_x_value ******************************************/
/**                                                       **/
/**   Limits a passed input value to some fraction        **/
/**   of the segment length defined by                    **/
/**   (x_upper - x_lower). The fractional value in        **/
/**   question is passed as a value to the routine        **/
/**   (fraction).                                         **/
/**                                                       **/
/**   9/25/91                                  JPM        **/
/***********************************************************/

static double limit_x_value(double x_lower,double x_upper, 
                            double x_input,double fraction, 
                            double *last_x_value)
{
    double max_x_delta,   /* maximum delta value permissible for 
                           this segment domain. */
                  hold;   /* Holding variable for previous x_input value */     


    /** Limit effective change of input to fraction of value of lowest **/
    /** x-segment length...                                            **/ 

    /* calculate maximum delta value for this region */
    max_x_delta = fraction * (x_upper - x_lower);

    /* Test new input */
    if ( max_x_delta < fabs(x_input - *last_x_value) ) {
                        
        hold = x_input;

        /* Assign new x_input based of direction of movement */
        /* since last iteration call                         */
        if ( 0.0 <= (x_input - *last_x_value) ) {
            x_input = *last_x_value = *last_x_value + max_x_delta;
        }
        else {
            x_input = *last_x_value = *last_x_value - max_x_delta;
        }

        /* Alert the simulator to non-convergence */
        cm_analog_not_converged();

        /*** Debugging printf statement ***/
        /* printf("Assigning new x_input...\nPrevious value=%e, New value=%e\n\n",
                hold,x_input);
        */   

    }
    else { /* No limiting of x_input required */
        *last_x_value = x_input;
    }
                          
    return x_input;

}

/*==============================================================================

FUNCTION void cm_pwl(>

AUTHORS                      

    19 Apr 1991     Jeffrey P. Murray

MODIFICATIONS   

    25 Sep 1991    Jeffrey P. Murray
     2 Oct 1991    Jeffrey P. Murray

SUMMARY

    This function implements the pwl code model.

INTERFACES       

    FILE                 ROUTINE CALLED     

    CMutil.c             void cm_smooth_corner(); 

    CMmacros.h           cm_message_send();                   
                             
    CM.c                 void cm_analog_not_converged()


RETURNED VALUE
    
    Returns inputs and outputs via ARGS structure.

GLOBAL VARIABLES
    
    NONE

NON-STANDARD FEATURES

    NONE

==============================================================================*/

/*=== CM_PWL ROUTINE ================*/

void cm_pwl(ARGS)  /* structure holding parms, 
                                   inputs, outputs, etc.     */
{
    int i;               /* generic loop counter index */
	int size;            /* size of the x_array        */

    double input_domain;    /* smoothing range */
    double *x;              /* pointer to the x-coordinate array */
    double *y;              /* pointer to the y-coordinate array */
    double lower_seg;       /* x segment below which input resides */
    double upper_seg;       /* x segment above which the input resides */
    double lower_slope;     /* slope of the lower segment */
    double upper_slope;     /* slope of the upper segment */
    double x_input;         /* input */
    double out;             /* output */
    double dout_din;        /* partial derivative of the output wrt input */
    double threshold_lower; /* value below which the output begins smoothing */
    double threshold_upper; /* value above which the output begins smoothing */
    double test1;           /* debug testing value */
    double test2;           /* debug testing value */
    double *last_x_value;   /* static variable for limiting */
    double test;            /* temp storage variable for limit testing */

    Mif_Complex_t ac_gain;
                                           
    char *allocation_error="\n***ERROR***\nPWL: Allocation calloc failed!\n";
    char *limit_error="\n***ERROR***\nPWL: Violation of 50% rule in breakpoints!\n";

    /* Retrieve frequently used parameters... */

    input_domain = PARAM(input_domain);

    size = PARAM_SIZE(x_array);