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Input Rules

FrontISTR input files (overall control data .dat, analysis control data .cnt, and mesh data .msh) follow common notation rules.

File Characteristics

  • They are free-format ASCII files.
  • They consist of headers beginning with ! followed by data.
  • The order in which headers are written is generally arbitrary.
  • A comma , is used as the data delimiter.

Note: Characteristics specific to analysis control data

Analysis control data (.cnt) has the following additional characteristics.

  • The file is broadly divided into three zones: calculation control data, solver control data, and post-processing (visualization) control data.
  • Enter !END at the end of the file to terminate it.

Identifies the meaning of the data and the data block. A line whose first character is ! is regarded as a header.

Header Line

Describes the header and its associated parameters.

  • A header line must begin with a header.
  • If parameters are required, they must follow it using ,.
  • If a parameter takes a value, the parameter is followed by =, and then the value is specified.
  • A header line cannot span multiple lines.

Data Lines

Begin on the line following the header line and describe the required data.

  • Data lines may span multiple lines; this is determined by the data description rules defined for each header.
  • Data lines may not be required.

Delimiter

A comma , is used as the data delimiter.

Whitespace Handling

Whitespace is ignored.

Names

Characters that may be used in names are underscore _, hyphen -, and alphanumeric characters a-z A-Z 0-9, but the first character must be _ or an alphabetic character a-z A-Z.

  • Names are case-insensitive and are treated internally as uppercase.
  • The maximum name length is 63 characters.

File Names

Characters that may be used in file names are underscore _, hyphen -, period ., slash /, and alphanumeric characters a-z A-Z 0-9.

  • Unless otherwise specified, file names may include paths. Both relative and absolute paths can be specified.
  • The maximum file name length is 1023 characters.

Floating-Point Data

An exponent may be present or omitted. An exponent must be preceded by E or e. Either E or e may be used.

Note:

D or d cannot be used.

Comment Lines

Lines beginning with !! or # are regarded as comment lines and ignored.

  • Comment lines can be inserted anywhere in the file, with no limit on their number.

!END

Indicates the end of the data. When this header appears, data reading terminates.