sci_files

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 constant 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. Syntax: dim = first_non_singleton(A)

  gettempvar

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

  insert

  allows to insert instructions. Syntax:m2sci_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. Syntax: [A,B] = getoperands(operation_tlist)

  getrhs

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

  convert2double

  change type of input when this type is not implemented for a particular function is Scilab. Syntax: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 the converted pseudo-code representing a function call
• Operation — Generates the Scilab pseudo-code representing an operation
• Variable — Generates the Scilab internal code representing a variable (without its content)
• Cste — Create a tree representing a constant
• Infer — Create a tree containing inference data
• Type — Create a tree containing type inference data
• Equal — Generates the Scilab internal code representing an instruction "LHS = RHS"