Mathematical expression

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Description

The Expression block applies the specified Scilab functions to its input.

Dialog Box

Give a scalar scilab expression using inputs u1, u2,...
ex: (dd*u1+sin(u2)$>$0)*u3
Note that here dd must be defined in context
number of inputs	2
scilab expression	(u1$>$0)*sin(u2)2
use zero-crossing (0: no, 1 yes)	1

• number of inputs: Block input can be a scalar or vector.
• scilab expression: The Scilab expression applied to the input.
• use zero-crossing :Select to enable zero crossing detection.

Default properties

• always active: no
• direct-feedthrough: yes
• zero-crossing: yes
• mode: yes
• number/sizes of inputs: 2 / 1 1
• number/sizes of outputs: 1 / 1
• number/sizes of activation inputs: 0 /
• number/sizes of activation outputs: 0 /
• continuous-time state: no
• discrete-time state: no
• name of computational function: evaluate_expr

Interfacing function

scilab/macros/scicos_blocks/misc/EXPRESSION.sci

Computational function (type 4)

#include "scicos_block.h"
#include <math.h>
#if WIN32
#include <float.h>
#endif

#if defined(solaris)
#include <ieeefp.h>
int isinf(double x) { return !finite(x) && x==x; }
#endif

#if WIN32
/*
arcsinh z = log (z+sqrt(1+z2))
*/
double asinh(double x)
{
  return log(x+sqrt(x*x+1));
}

double acosh(double x)
{
  return log(x+sqrt(x*x-1));
}

/* atanh(x)
 *      For x>=0.5
 *                  1              2x                          x
 *	atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
 *                  2             1 - x                      1 - x
 *	
 * 	For x<0.5
 *	atanh(x) = 0.5*log1p(2x+2x*x/(1-x))
 *
 */

double atanh(double x)
{
	if (x >=0.5) 
	{
		return 0.5*log((1+x)/(1-x));
	}
	else
	{
		return 0.5*log((2*x)+(2*x)*x/(1-x));
	}
  
}
#endif

void evaluate_expr(scicos_block *block,int flag)
{
  static double stack [1000];
  static int count,bottom,nzcr,i,phase; 
  int j;  
  if (flag==1||flag==9){
    phase=get_phase_simulation();
    bottom=-1;
    count=-1;
    nzcr=-1;
    while (count<block->nipar-1){
      count=count+1;
      switch (block->ipar[count]) {
      case 2:
	count=count+1;
	bottom=bottom+1;
	if(bottom>999){
	  set_block_error(-16);
	  return;
	}
	if (block->nin>1){
	  stack[bottom]=block->inptr[block->ipar[count]-1][0];
	}else{
	  j=block->ipar[count]-1;
	  if (j<block->insz[0]){
	    stack[bottom]=block->inptr[0][block->ipar[count]-1];
	  }else{
	    stack[bottom]=0.;
	  }
	}
	break;
      case 6:
	count=count+1;
	bottom=bottom+1;
	if(bottom>999){
	  set_block_error(-16);
	  return;
	}
	stack[bottom]=block->rpar[block->ipar[count]-1];
	break;
      case 5:
	count=count+1;
	switch (block->ipar[count]) {
	case 1:
	  stack[bottom-1]=stack[bottom-1]+stack[bottom];
	  bottom=bottom-1;
	  break;
	case 2:
	  stack[bottom-1]=stack[bottom-1]-stack[bottom];
	  bottom=bottom-1;
	  break;
	case 3:
	  stack[bottom-1]=stack[bottom-1]*stack[bottom];
	  bottom=bottom-1;
	  break;
	case 7:
	  stack[bottom-1]=stack[bottom-1]/stack[bottom];
	  bottom=bottom-1;
	  break;
	case 15:
	  stack[bottom-1]=pow(stack[bottom-1],stack[bottom]);
	  bottom=bottom-1;
	  break;
	case 16: /* case == */
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]==stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]==stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;

	case 17:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]<stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]<stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 18:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]>stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]>stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 19:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]<=stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]<=stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 20:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]>=stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]>=stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 21:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(stack[bottom-1]!=stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=(stack[bottom-1]!=stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 28:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=((int)stack[bottom-1]||(int)stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=((int)stack[bottom-1]||(int)stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;
	case 29:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom-1]-stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=((int)stack[bottom-1]&&(int)stack[bottom]);
	    }
	  }
	  if(phase==1||block->ng==0){
	    i=((int)stack[bottom-1]&&(int)stack[bottom]);
	  } else{
	    i=block->mode[nzcr];
	  }
	  stack[bottom-1]=(double)i;
	  bottom=bottom-1;
	  break;

	case 30:
	  if (flag==9) {
	    block->g[nzcr]=stack[bottom];
	    if(phase==1) {
	      block->mode[nzcr]=(0.0==stack[bottom]);
	    }
	  }
	  if(block->ng>0) nzcr=nzcr+1;
	  if(phase==1||block->ng==0){
	    i=(stack[bottom]==0.0);
	  }else{
	    i=block->mode[nzcr];
	  }
	  if (i){
	    stack[bottom]=1.0;
	  }else{
	    stack[bottom]=0.0;   
	  }
	  break;
	case 99:
	  stack[bottom]=-stack[bottom];
	  break;
	case 101:
	  stack[bottom]=sin(stack[bottom]);
	  break;
	case 102:
	  stack[bottom]=cos(stack[bottom]);
	  break;
	case 103:
	  stack[bottom]=tan(stack[bottom]);
	  break;
	case 104:
	  stack[bottom]=exp(stack[bottom]);
	  break;
	case 105:
	  stack[bottom]=log(stack[bottom]);
	  break;
	case 106:
	  stack[bottom]=sinh(stack[bottom]);
	  break;
	case 107:
	  stack[bottom]=cosh(stack[bottom]);
	  break;
	case 108:
	  stack[bottom]=tanh(stack[bottom]);
	  break;

	case 109:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]>0) {
	      i=floor(stack[bottom]);
	    }else{
	      i=ceil(stack[bottom]);
	    }
	    if(i==0)  {
	      block->g[nzcr]=(stack[bottom]-1)*(stack[bottom]+1);
	    }else if(i>0){
	      block->g[nzcr]=(stack[bottom]-i-1.)*(stack[bottom]-i);
	    }else{
	      block->g[nzcr]=(stack[bottom]-i)*(stack[bottom]-i+1);
	    }
	    if(i%2)  block->g[nzcr]=-block->g[nzcr];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    if (stack[bottom]>0) {
	      stack[bottom]=floor(stack[bottom]);
	    }else{
	      stack[bottom]=ceil(stack[bottom]);
	    }
	  }else{
	    stack[bottom]=(double) block->mode[nzcr];
	  }
	  break;
	  /*
	  if (stack[bottom]>0) {
	    stack[bottom]=floor(stack[bottom]);
	  }else{
	    stack[bottom]=ceil(stack[bottom]);
	    }*/
	  break;
	case 110:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]>0) {
	      i=floor(stack[bottom]+.5);
	    }else{
	      i=ceil(stack[bottom]-.5);
	    }
	    block->g[nzcr]=(stack[bottom]-i-.5)*(stack[bottom]-i+.5);
	    if(i%2)  block->g[nzcr]=-block->g[nzcr];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    if (stack[bottom]>0) {
	      stack[bottom]=floor(stack[bottom]+.5);
	    }else{
	      stack[bottom]=ceil(stack[bottom]-.5);
	    }
	  }else{
	    stack[bottom]=(double) block->mode[nzcr];
	  }
	  break;
	  /*  if (stack[bottom]>0) {
	    stack[bottom]=floor(stack[bottom]+.5);
	  }else{
	    stack[bottom]=ceil(stack[bottom]-.5);
	  }*/
	case 111:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    i=ceil(stack[bottom]);
	    block->g[nzcr]=(stack[bottom]-i)*(stack[bottom]-i+1);
	    if(i%2)  block->g[nzcr]=-block->g[nzcr];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    stack[bottom]=ceil(stack[bottom]);
	  }else{
	    stack[bottom]=(double) block->mode[nzcr];
	  }
	  break;
	case 112:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    i=floor(stack[bottom]);
	    block->g[nzcr]=(stack[bottom]-i-1)*(stack[bottom]-i);
	    if(i%2)  block->g[nzcr]=-block->g[nzcr];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    stack[bottom]=floor(stack[bottom]);
	  }else{
	    stack[bottom]=(double) block->mode[nzcr];
	  }
	  break;
	case 113:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]>0) {
	      i=1;
	    }else if (stack[bottom]<0){
	      i=-1;
	    }else{
	      i=0;
	    }
	    block->g[nzcr]=stack[bottom];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    if (stack[bottom]>0) {
	      stack[bottom]=1.0;
	    }else if(stack[bottom]<0){
	      stack[bottom]=-1.0;
	    }else{
	      stack[bottom]=0.0;
	    }
	  }else{
	    stack[bottom]=(double) block->mode[nzcr];
	  }
	  break;
	  /* if (stack[bottom]>0) {
	    stack[bottom]=1.0;
	  }else if(stack[bottom]<0){
	    stack[bottom]=-1.0;
	  }else{
	    stack[bottom]=0.0;
	    }*/
	case 114:  /* abs */
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]>0) {
	      i=1;
	    }else if (stack[bottom]<0){
	      i=-1;
	    }else{
	      i=0;
	    }
	    block->g[nzcr]=stack[bottom];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    if (stack[bottom]>0) {
	      stack[bottom]=stack[bottom];
	    }else {
	      stack[bottom]=-stack[bottom];
	    }
	  }else{
	    stack[bottom]=stack[bottom]*(block->mode[nzcr]);
	  }
	  break;
	  /* if (stack[bottom]>0) {
	    stack[bottom]=stack[bottom];
	  }else {
	    stack[bottom]=-stack[bottom];
	    }*/
	case 115:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]>stack[bottom-1]) {
	      i=0;
	    }else {
	      i=1;
	    }
	    block->g[nzcr]=stack[bottom]-stack[bottom-1];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    stack[bottom-1]=max(stack[bottom-1],stack[bottom]);
	  }else{
	    stack[bottom-1]=stack[bottom-block->mode[nzcr]];
	  }
	  bottom=bottom-1;
	  break;
	case 116:
	  if(block->ng>0) nzcr=nzcr+1;
	  if (flag==9) {
	    if (stack[bottom]<stack[bottom-1]) {
	      i=0;
	    }else {
	      i=1;
	    }
	    block->g[nzcr]=stack[bottom]-stack[bottom-1];
	    if(phase==1) block->mode[nzcr]=i;
	  }
	  if(phase==1||block->ng==0){
	    stack[bottom-1]=min(stack[bottom-1],stack[bottom]);
	  }else{
	    stack[bottom-1]=stack[bottom-block->mode[nzcr]];
	  }
	  bottom=bottom-1;
	  break;
	case 117:
	  stack[bottom]=asin(stack[bottom]);
	  break;
	case 118:
	  stack[bottom]=acos(stack[bottom]);
	  break;
	case 119:
	  stack[bottom]=atan(stack[bottom]);
	  break;
	case 120:
	  stack[bottom]=asinh(stack[bottom]);
	  break;
	case 121:
	  stack[bottom]=acosh(stack[bottom]);
	  break;
	case 122:
	  stack[bottom]=atanh(stack[bottom]);
	  break;
	case 123:
	  stack[bottom-1]=atan2(stack[bottom-1],stack[bottom]);
	  bottom=bottom-1;
	  break;

	case 124:
	  stack[bottom]=log10(stack[bottom]);
	  break;
	}
      }
    }
    #if WIN32
    if(!_finite(stack[bottom])||_isnan(stack[bottom])){
    #else
     if(isinf(stack[bottom])||isnan(stack[bottom])){
    #endif
      set_block_error(-2);
      return;
    }else{
      block->outptr[0][0]=stack[bottom];
    }
  }
}