Log
Keywords: main

Subsections

- Library
- Description
- Dialog Box
- Default properties
- Interfacing function
- Computational function (type 0)

##
Log

### Library

Non_linear

### Description

This block realizes . 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