WOLFRAM SYSTEMMODELER

CombiTable1Ds

Table look-up in one dimension (matrix/file) with one input and n outputs

Wolfram Language

In[1]:=
Click for copyable input
SystemModel["Modelica.Blocks.Tables.CombiTable1Ds"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

Linear interpolation in one dimension of a table. Via parameter columns it can be defined how many columns of the table are interpolated. If, e.g., icol={2,4}, it is assumed that one input and 2 output signals are present and that the first output interpolates via column 2 and the second output interpolates via column 4 of the table matrix.

The grid points and function values are stored in a matrix "table[i,j]", where the first column "table[:,1]" contains the grid points and the other columns contain the data to be interpolated. Example:

   table = [0,  0;
            1,  1;
            2,  4;
            4, 16]
   If, e.g., the input u = 1.0, the output y =  1.0,
       e.g., the input u = 1.5, the output y =  2.5,
       e.g., the input u = 2.0, the output y =  4.0,
       e.g., the input u =-1.0, the output y = -1.0 (i.e., extrapolation).
  • The interpolation is efficient, because a search for a new interpolation starts at the interval used in the last call.
  • If the table has only one row, the table value is returned, independent of the value of the input signal.
  • If the input signal u is outside of the defined interval, i.e., u > table[size(table,1),1] or u < table[1,1], the corresponding value is also determined by linear interpolation through the last or first two points of the table.
  • The grid values (first column) have to be strictly increasing.

The table matrix can be defined in the following ways:

  1. Explicitly supplied as parameter matrix "table", and the other parameters have the following values:
       tableName is "NoName" or has only blanks,
       fileName  is "NoName" or has only blanks.
    
  2. Read from a file "fileName" where the matrix is stored as "tableName". Both ASCII and MAT-file format is possible. (The ASCII format is described below). The MAT-file format comes in four different versions: v4, v6, v7 and v7.3. The library supports at least v4, v6 and v7 whereas v7.3 is optional. It is most convenient to generate the MAT-file from FreeMat or MATLAB® by command
       save tables.mat tab1 tab2 tab3
    
    or Scilab by command
       savematfile tables.mat tab1 tab2 tab3
    
    when the three tables tab1, tab2, tab3 should be used from the model.
    Note, a fileName can be defined as URI by using the helper function loadResource.
  3. Statically stored in function "usertab" in file "usertab.c". The matrix is identified by "tableName". Parameter fileName = "NoName" or has only blanks. Row-wise storage is always to be preferred as otherwise the table is reallocated and transposed. See the Tables package documentation for more details.

When the constant "NO_FILE_SYSTEM" is defined, all file I/O related parts of the source code are removed by the C-preprocessor, such that no access to files takes place.

If tables are read from an ASCII-file, the file needs to have the following structure ("-----" is not part of the file content):

-----------------------------------------------------
#1
double tab1(5,2)   # comment line
  0   0
  1   1
  2   4
  3   9
  4  16
double tab2(5,2)   # another comment line
  0   0
  2   2
  4   8
  6  18
  8  32
-----------------------------------------------------

Note, that the first two characters in the file need to be "#1" (a line comment defining the version number of the file format). Afterwards, the corresponding matrix has to be declared with type (= "double" or "float"), name and actual dimensions. Finally, in successive rows of the file, the elements of the matrix have to be given. The elements have to be provided as a sequence of numbers in row-wise order (therefore a matrix row can span several lines in the file and need not start at the beginning of a line). Numbers have to be given according to C syntax (such as 2.3, -2, +2.e4). Number separators are spaces, tab (\t), comma (,), or semicolon (;). Several matrices may be defined one after another. Line comments start with the hash symbol (#) and can appear everywhere. Other characters, like trailing non comments, are not allowed in the file.

MATLAB is a registered trademark of The MathWorks, Inc.

Connectors (2)

u

Type: RealInput

Description: Connector of Real input signal

y

Type: RealOutput[nout]

Description: Connector of Real output signals

Parameters (9)

nout

Value: size(columns, 1)

Type: Integer

Description: Number of outputs

tableOnFile

Value: false

Type: Boolean

Description: = true, if table is defined on file or in function usertab

table

Value: fill(0.0, 0, 2)

Type: Real[:,:]

Description: Table matrix (grid = first column; e.g., table=[0,2])

tableName

Value: "NoName"

Type: String

Description: Table name on file or in function usertab (see docu)

fileName

Value: "NoName"

Type: String

Description: File where matrix is stored

verboseRead

Value: true

Type: Boolean

Description: = true, if info message that file is loading is to be printed

columns

Value: 2:size(table, 2)

Type: Integer[:]

Description: Columns of table to be interpolated

smoothness

Value: Modelica.Blocks.Types.Smoothness.LinearSegments

Type: Smoothness

Description: Smoothness of table interpolation

tableOnFileRead

Value:

Type: Real

Description: = 1, if table was successfully read from file

Components (1)

tableID

Type: ExternalCombiTable1D

Description: External table object

Used in Examples (4)

AIMC_withLosses

Test example: AsynchronousInductionMachineSquirrelCage with losses

ForceCurrentBehaviour

Comparison of the force-current characteristics of both converter models with armature blocked at mid-position

ForceStrokeBehaviour

Force-stroke characteristic of the permeance model at constant current

ComparisonQuasiStationary

Slow forced armature motion of both solenoid models so that electromagnetic field and current are quasi-stationary