Predefined Fortran functions in MUSUBI

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  4. Predefined Fortran functions in MUSUBI

On this page we would like to introduce a list of predefined fortran functions that can be used in Musubi and a tutorial on how to use them.

Predefined space time functions

To distinguish between spatial and transient function one uses the variable table. Use combined to provide a temporal and a spatial table. Each can be either a constant, a lua function, a predefined function or a space time function. Here is an example:

variable = {
  {
    name = 'vel_x',
    ncomponents = 1,
    vartype = 'st_fun',
    st_fun = {
      predefined = 'combined',
      temporal = {
        ...
      }, -- temporal
      spatial = {
        ...
      } -- spatial
    } -- st_fun
  }, -- vel_x
} -- variable

Predefined spatial funtions

  • Parabolic profile
  • Random distribution

Parabolic profile

You can use the parabolic profile if you provide the shape of the parabol and the amplitude.

Here is an example on how to you use it.

variable = {
  {
    name = 'vel_x',
    ncomponents = 1,
    vartype = 'st_fun',
    st_fun = {
      predefined = 'combined',
      temporal = {
        ...
      }, -- temporal
      spatial = {
        predefined ='parabol',
        shape = {
          kind = 'canoND',
          object = {
            center  = {-8.0, 0.0, 0.0},
            halfvec = {{0.0, 1.0, 0.0}, {0.0, 0.0, 1.0}}
          } -- object
        }, -- shape
        amplitude = 1.0
      } -- spatial
    } -- st_fun
  }, -- vel_x
  ...
} -- variable

Random distribution

You can use random numbers for the spatial part. Example:

variable = {
  {
    name = 'vel_x',
    ncomponents = 1,
    vartype = 'st_fun',
    st_fun = {
      predefined = 'combined',
      temporal = {
        ...
      }, -- temporal
      spatial = {
        predefined ='random',
        min = 0.0, -- default
        max = 1.0 -- default
      } -- spatial
    } -- st_fun
  }, -- vel_x
  ...
} -- variable

Predefined temporal functions

  • linear, smooth
  • datafile
  • cos

Linear and Smooth

Here is an example on how to use the linear and smooth functionality for spacetime functions.

variable = {
  {
    name = 'vel_x',
    ncomponents = 1,
    vartype = 'st_fun',
    st_fun = {
      predefined = 'combined',
      spatial = 1.0, -- as an example
      temporal = {
        predefined = {
          kind = 'linear', -- or 'smooth'
          minfactor = 0.0, -- default = 0.0
          maxfactor = 1.0, -- default = 1.0
          from_time = 0, -- default = 0.0
          to_time = 1000, -- default = 1.0
        } -- predefined
      } -- temporal
    } -- st_fun
  } -- vel_x
} -- variable

The following graphs show the differences between smooth and linear.

linear_smooth

Using data files

temporal = {
  kind = 'predefined',
  predefined = {
    kind = 'datafile',
    filename = '...',
    intp = '...',
    ramping = { -- possible
      rampVal = ..., -- ramping value
      rampT = ... -- ramping time
    },
    fac = 1.0, -- default
    periodic = 'false' -- default
  } -- predefined
} -- temporal

Using cosine function

temporal = {
  kind = 'predefined',
  predefined = {
    kind = 'cos',
    frequency = 1.0, -- default
    phase = 0.0, -- default
    offset = 0.0 -- default
  } -- predefined
} -- temporal