<div dir="ltr">Try running with -ts_view and -options_left and send all of the output.</div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 11, 2017 at 1:12 PM, Ali Berk Kahraman <span dir="ltr"><<a href="mailto:aliberkkahraman@yahoo.com" target="_blank">aliberkkahraman@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello All,<br>
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I am trying to use timesteppers, however I have a problem. Whenever I want to set a dt for the timstepping integration, I cannot succeed. Neither the function TSSetTimeStep nor the command line option seems to work. Using either of them(but not at the same time) and setting it to 1, when I call TSGetTimeStep to learn the value of dt, it gives me the answer 0.002871. Perhaps this is the default value, however I cannot work with this, since the equation I have is slowly evolving.<br>
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Any ideas what might be causing this?<br>
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The part of the code I use,<br>
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PetscReal time=0, timestep=1;<br>
    int maxsteps=30;<br>
    float maxtime=300;<br>
<br>
<br>
        TS ts;<br>
        ierr= TSCreate(PETSC_COMM_WORLD,&ts)<wbr>;<br>
        CHKERRQ(ierr);<br>
        ierr= TSSetProblemType(ts,TS_LINEAR)<wbr>;<br>
        CHKERRQ(ierr);<br>
        ierr= TSSetSolution(ts, dummyvec);<br>
        CHKERRQ(ierr);<br>
        ierr= TSSetType(ts,TSRK);<br>
        CHKERRQ(ierr);<br>
        ierr= TSSetTime(ts,time);<br>
        CHKERRQ(ierr);<br>
        ierr= TSSetTimeStep(ts,timestep);<br>
        CHKERRQ(ierr);<br>
        ierr=TSSetExactFinalTime(ts,TS<wbr>_EXACTFINALTIME_STEPOVER);<br>
        CHKERRQ(ierr);<br>
        TSSetMaxSteps(ts,maxsteps);<br>
        TSSetMaxTime(ts,maxtime);<br>
<br>
        ierr=TSSetFromOptions(ts);CHKE<wbr>RRQ(ierr);<br>
        TSSetRHSFunction(ts,residual,<br>
                         FormRHSFunction,&mycontext);<br>
        ierr= TSSolve(ts,uJi);<br>
        CHKERRQ(ierr);<br>
        TSView(ts,PETSC_VIEWER_STDOUT_<wbr>SELF);<br>
<br>
        TSConvergedReason reason;<br>
        ierr=TSGetConvergedReason(ts,&<wbr>reason);CHKERRQ(ierr);<br>
        printf("Why Converged: %d\n",reason);<br>
        PetscReal usedtimestep;<br>
        TSGetTimeStep(ts,&usedtimestep<wbr>);<br>
        printf("Used timestep: %f\n",usedtimestep);<br>
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</blockquote></div><br></div>