DIF1

Returns the time derivative of the state variable defined by the Control_Diff element.

Format

DIF1(id)

Description

For implicit Control_Diff elements, the time derivative is approximate, obtained using numerical differentiation.

Arguments

id: The ID of the Control_Diff element.

Example

<Force_Vector_TwoBody
     id                   = "30101"
     type                 = "ForceOnly"
     i_marker_id          = "30102040"
     body1_id             = "30102"
     j_floating_marker_id = "30101041"
     body2_id             = "30101"
     ref_marker_id        = "30101010"
     ref_body_id          = "30101"
     fx_expression        = "0"
     fy_expression        = "0"
     fz_expression        = "0.01*DIF(301001)+
                             0.0001*DIF1(301001)"
  />  
<Control_Diff
     label                = "Diff/301001"
     id                   = "301001"
     is_implicit          = "FALSE"
     ic                   = "0."
     ic_dot               = "0."
     is_static_hold       = "FALSE"
     type                 = "EXPRESSION"
     expr                 = "DZ(30102020,30101010)"
  />