Log

Library

Non_linear

Description

This block realizes $y(i)=log(u(i))/log(a)$ . The input and output port sizes are determined by the context.

Dialog Box

Set log block parameters
Basis ($>$1)	%e

• Basis : A real scalar greater than 1.

Default properties

• always active: no
• direct-feedthrough: yes
• zero-crossing: no
• mode: no
• number/sizes of inputs: 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: logblk

Interfacing function

scilab/macros/scicos_blocks/nonlinear/LOGBLK_f.sci

Computational function (type 0)

      subroutine logblk(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,
     &     rpar,nrpar,ipar,nipar,u,nu,y,ny)
c     Copyright INRIA


c     Scicos block simulator
c     y=log(u)/log(rpar(1))
c
      double precision t,xd(*),x(*),z(*),tvec(*),rpar(*),u(*),y(*)
      integer flag,nevprt,nx,nz,ntvec,nrpar,ipar(*)
      integer nipar,nu,ny

c
      if(flag.eq.1) then
         do 15 i=1,nu
            if(u(i).gt.0.0d0) then
               y(i)=log(u(i))/log(rpar(1))
            else
               flag=-2
               return
            endif
 15      continue
      endif
      if(flag.eq.6) then
         do 20 i=1,nu
            if(u(i).gt.0.0d0) then
               y(i)=log(u(i))/log(rpar(1))
            endif
 20      continue
      endif

      end