00001 /*****************************************************************************
00002    Major portions of this software are copyrighted by the Medical College
00003    of Wisconsin, 1994-2000, and are released under the Gnu General Public
00004    License, Version 2.  See the file README.Copyright for details.
00005 ******************************************************************************/
00006    
00007 /*
00008   This file contains routines to initialize and implement the 
00009   triangular wave (amplitude, phase, and frequency parameters) signal model.
00010 
00011   File:     model_trnglrwave_apf.c
00012   Author:   B. Douglas Ward
00013   Date:     29 May 1997
00014 */
00015 
00016 
00017 /*---------------------------------------------------------------------------*/
00018 
00019 #include <math.h>
00020 #include "NLfit_model.h"
00021 
00022 void signal_model 
00023 (
00024   float * gs,                /* parameters for signal model */
00025   int ts_length,             /* length of time series data */
00026   float ** x_array,          /* independent variable matrix */
00027   float * ts_array           /* estimated signal model time series */  
00028 );
00029 
00030 
00031 /*---------------------------------------------------------------------------*/
00032 /*
00033   Routine to initialize the signal model by defining the number of parameters
00034   in the signal model, the name of the signal model, and the default values
00035   for the minimum and maximum parameter constraints.
00036 */
00037 
00038 DEFINE_MODEL_PROTOTYPE
00039 
00040 MODEL_interface * initialize_model ()
00041 {
00042   MODEL_interface * mi = NULL;
00043 
00044 
00045   /*----- allocate memory space for model interface -----*/
00046   mi = (MODEL_interface *) XtMalloc (sizeof(MODEL_interface));
00047 
00048 
00049   /*----- define interface for the triangular wave model -----*/   
00050 
00051   /*----- name of this model -----*/
00052   strcpy (mi->label, "TrnglrWave_APF");
00053 
00054   /*----- this is a signal model -----*/
00055   mi->model_type = MODEL_SIGNAL_TYPE;
00056 
00057   /*----- number of parameters in the model -----*/
00058   mi->params = 3;
00059 
00060   /*----- parameter labels -----*/
00061   strcpy (mi->plabel[0], "amplitude");
00062   strcpy (mi->plabel[1], "phase");
00063   strcpy (mi->plabel[2], "frequency");
00064 
00065   /*----- minimum and maximum parameter constraints -----*/
00066   mi->min_constr[0] =   -100.0;    mi->max_constr[0] =   100.0;
00067   mi->min_constr[1] =    -90.0;    mi->max_constr[1] =     0.00;
00068   mi->min_constr[2] =      0.1;    mi->max_constr[2] =     0.15;
00069   
00070   /*----- function which implements the model -----*/
00071   mi->call_func = &signal_model;
00072 
00073 
00074   /*----- return pointer to the model interface -----*/
00075   return (mi);
00076 }
00077 
00078 
00079 /*---------------------------------------------------------------------------*/
00080 /*
00081   Routine to calculate the time series which results from using the
00082   triangular wave model with specified amplitude, phase, and frequency
00083   model parameters.
00084 
00085   Definition of model parameters:
00086 
00087         gs[0] = amplitude of triangular wave
00088         gs[1] = phase angle of triangular wave (degrees)
00089         gs[2] = frequency of triangular wave (cycles / time_step)
00090 */
00091 
00092 void signal_model 
00093 (
00094   float * gs,                /* parameters for signal model */
00095   int ts_length,             /* length of time series data */
00096   float ** x_array,          /* independent variable matrix */
00097   float * ts_array           /* estimated signal model time series */  
00098 )
00099 
00100 {
00101   int it;                           /* time index */     
00102   float t;                          /* time */
00103   float fval;                       /* time series value at time t */  
00104   float cycles;                     /* number of cycles since initial time */
00105 
00106 
00107   /*----- calculate time series corresponding to the given parameters -----*/
00108   for (it = 0;  it < ts_length;  it++)
00109     {
00110       t = x_array[it][1];
00111       cycles = gs[2]*t + gs[1]/360.0;
00112       cycles = cycles - (int)cycles;
00113       if (cycles <= 0.25)
00114         fval = gs[0] * (cycles/0.25);
00115       else
00116         if ((cycles > 0.25) && (cycles <= 0.75))
00117           fval = gs[0] * (2.0 - (cycles/0.25));
00118         else
00119           fval = gs[0] * ((cycles/0.25) - 4.0);
00120       ts_array[it] = fval;      
00121     }
00122 }
00123 
00124 
00125 
00126