Scilab Home page | Wiki | Bug tracker | Forge | Mailing list archives | ATOMS | File exchange
Please login or create an account
Change language to: English - Français - Português - 日本語

Please note that the recommended version of Scilab is 6.0.0. This page might be outdated.
See the recommended documentation of this function

Справка Scilab >> Matlab to Scilab Conversion Tips > sci_files

sci_files

How to write conversion functions

Description

To convert calls to Matlab functions, mfile2sci uses a function called sci_<Matlab_function_name>. All these functions are defined in sci_files in directory SCI/modules/m2sci/macros/sci_files/. The set of sci_files given in Scilab distribution does not allow to convert calls to all Matlab functions yet. However, a Scilab user can add sci_files (for Matlab functions or for user defined functions) to Scilab using the following tips.

In M2SCI, a function call is considered as a "tree" (it is also the case for the instructions of the file to convert), represented in Scilab by a tlist with following fields:

  • name

    Matlab function name

    lhsnb

    number of Matlab function output parameters

    lhs

    list of Matlab function output parameters

    rhs

    list of Matlab function input parameters

A sci_function has one input called tree which is also the output of the function. A sci_function has to convert this incoming "tree" so that it is compatible with Scilab by changing name, lhsnb, lhs and/or rhs. The other task that has to be done by this function is inference. Incoming tree contains inference data in its lhs that have to be updated with what can be infered for the outputs of this function.

Some useful functions have been written to help to create M2SCI tlists while writing this conversion function:

  • Funcall

    create a tree representing a function call

    Operation

    create a tree representing an operation

    Variable

    create a tree representing a variable

    Cste

    create a tree representing a constante value

    Infer

    create a tree representing inference data

    Type

    create a tree representing type for inference

    Equal

    create a tree representing an instruction

Some other functions have been designed to get properties of operands/inputs. Considering A is tlist used in macro tree, you can use the following functions:

Function returns %T if...
is_empty(A) all dimensions of A are 0
not_empty(A) all dimensions of A are known and at least one dimension of A is not 0
is_a_scalar(A) all dimensions of A are 1
not_a_scalar(A) all dimensions of A are known and at least one dimension of A is not 1
is_a_vector(A) all dimensions of A are known and all dimensions of A but one are equal to 1
not_a_vector(A) all dimensions of A are known and at least two dimensions of A are greater than one
is_real(A) A is real
is_complex(A) A is complex
isdefinedvar(A) A is a variable already created in M-file currently converted
allunknown(A) all dimensions of A are unknown

Some other functions have been written for specific needs while writing conversion files:

  • first_non_singleton

    is an equivalent to firstnonsingleton for an M2SCI tlist. Calling sequence: dim = first_non_singleton(A)

    gettempvar

    generates a temporary variable having a name which does not already exist. Calling sequence:v = gettempvar()

    insert

    allows to insert instructions. Calling sequence:insert(Equal(...),opt) with opt~=1 to insert before current instruction and opt=1 to insert after it.

    getoperands

    can be used to get each operand as a variable. Calling sequence: [A,B] = getoperands(operation_tlist)

    getrhs

    can be used to get each parameter as a variable. Calling sequence: [A,...] = getrhs(funcall_tlist)

    convert2double

    change type of input when this type is not implemented for a particular function is Scilab. Calling sequence:A = convert2double(A)

To have more information about how to write such files, refer to directory SCI/modules/m2sci/macros/sci_files/ which gives many examples from very simple ones (e.g. sci_abs.sci) to very complex ones (e.g. sci_zeros.sci).

See Also

  • m2scideclare — Giving tips to help M2SCI...
  • Funcall — Create a tree representing a function call
  • Operation — Create a tree representing an operation
  • Variable — Create a tree representing a variable
  • Cste — Create a tree representing a constant
  • Infer — Create a tree containing inference data
  • Type — Create a tree containing type inference data
  • Equal — Create a tree representing an instruction
Scilab Enterprises
Copyright (c) 2011-2017 (Scilab Enterprises)
Copyright (c) 1989-2012 (INRIA)
Copyright (c) 1989-2007 (ENPC)
with contributors
Last updated:
Thu Oct 02 14:01:18 CEST 2014