In Fortran 90 programs, the value of the kind type parameter for a given data type can be specified by the KIND intrinsic function. Dc_types module of gt4f90io provides standard type parameters. By using the dc_trace module, it is not necessary to define type parameters in user's programs.
For example, a sample program using the dc_trace module (diffusion_3.f90) is shown here, which are modified from diffusion_2.f90 in Data I/O interface: (3) Add attribute. Statements with colored font (or bold font) are associated with the dc_types module.
!= Sample program for gt4_history/gt4f90io ! ! * 2007/06/25 M.Odaka ! * 2006/10/25 Y.Morikawa ! * 2003/08/21 M.Odaka ! * 2001/02/27 S.Takehiro ! ! Solving diffusion equation ! \[ ! du/dt = \kappa d^2 u/dx^2 ! \] ! for giving values of $u$ at $x=[0,1]$. ! program diffusion_3 use gt4_history ! モジュール指定 use dc_types, only : DP ! モジュール指定 integer, parameter :: nx=30 ! グリッド数 integer, parameter :: nt=200 ! 時間ステップ数 integer, parameter :: ndisp=10 ! 出力間隔 real(DP), parameter :: dx=1.0/(nx-1) ! グリッド間隔 real(DP), parameter :: dt=0.0005 ! 時間間隔 real(DP), dimension(nx):: x=(/(dx*(i-1),i=1,nx)/) ! 座標変数 real(DP), dimension(nx):: temp ! 温度 real(DP), parameter :: kappa=1.0 ! 熱拡散係数 tinit = 0.0 ! 初期時刻設定 temp = exp(-((x-0.5)/0.1)**2) ! 初期値設定 call HistoryCreate( & ! ヒストリー作成 & file='diffusion_3.nc', title='Diffusion equation', & & source='Sample program of gt4_history/gt4f90io', & & institution='GFD_Dennou Club davis project', & & dims=(/'x','t'/), dimsizes=(/nx,0/), & & longnames=(/'X-coordinate','time '/), & & units=(/'m','s'/), & & origin=real(tinit), interval=real(ndisp*dt) ) call HistoryPut('x',x) ! 次元変数出力 call HistoryAddVariable( & ! 変数定義 & varname='temp', dims=(/'x','t'/), & & longname='temperature', units='K', xtype='double') call HistoryAddAttr('temp','gt_graph_tick_all',1) call HistoryAddAttr('temp','gt_graph_contour_spacing',(/0.0,1.0,0.01/)) call HistoryAddAttr('temp','+gt_user_davis_kappa',kappa) call HistoryPut('temp',temp) ! 変数出力 do it=1,nt temp(2:nx-1) = temp(2:nx-1) & ! 時間積分 & + kappa*(temp(3:nx)-2*temp(2:nx-1)+temp(1:nx-2))/dx**2*dt if ( mod(it,ndisp) == 0 ) then call HistoryPut('temp',temp) ! 変数出力 endif enddo call HistoryClose stop end program diffusion_3
In this sample program, the parameter DP provided by dc_trace module is used as the kind type parameter for double precision real literal constant. The dc_trace module also provides kind type parameters for integer and character literal constants. In detail, please see gt4f90io reference manual.