Dear Anup,
The simplest explanation that I can give is that, in its original form, the
implementation of the Time class in step-44 is not suitable for your needs
and you need to adjust it accordingly. If you need to change that value of
delta_t, then you should add some function that does it for you. What have
you tried so far that has not worked so far? I've annotated what I think
you'd likely have to do here:
class Time
{
public:
Time (const double time_end,
const double delta_t) // This should now be delta_t_0
:
timestep(0),
time_current(0.0),
time_end(time_end),
delta_t(delta_t) // Needs correct initialisation value
// Need to initialise value of delta_t_0
{}
virtual ~Time()
{}
double current() const
{
return time_current;
}
double end() const
{
return time_end;
}
double get_delta_t() const
{
return delta_t;
}
// Need a new function set_delta_t that changes the timestep size
unsigned int get_timestep() const
{
return timestep;
}
void increment()
{
time_current += delta_t;
++timestep;
}
private:
unsigned int timestep;
double time_current;
const double time_end;
const double delta_t; // This should not be const, as you want to
change its value
// Need a new member delta_t_0
};
Then you'd change the timestep size by calling time.set_delta_t(/*value*/).
Regards,
J-P
On Sunday, September 4, 2016 at 1:41:39 AM UTC+2, Anup Basak wrote:
>
> Dear Jean-Paul,
>
> Thank you for your reply.
>
> I, in fact, have done that way only. I have defined the initial time step
> through .prm file. Now my question is that
> after I update my time step in the run() function how can I pass this new
> time step, say 'delta_t' to the class 'Time'
> to obtain other parameters like current_time etc.
>
> Thanks and regards,
> Anup.
>
> On Wed, Aug 31, 2016 at 12:27 AM, Jean-Paul Pelteret <> wrote:
>
>> Dear Anup,
>>
>> Why don't you reinterpret the parameter passed as "delta_t" to be the
>> initial timestep size "delta_t_0" and then adjust the current timestep size
>> "delta_t" however you want? How you do this adjustment algorithm-wise is,
>> of course, entirely up to you.
>>
>> Regards,
>> J-P
>>
>>
>> On Tuesday, August 30, 2016 at 7:02:41 PM UTC+2, Anup Basak wrote:
>>>
>>> Hello all,
>>>
>>> I was trying to implement an adaptive time step in step44. In the given
>>> example 'delta_t' has been considered to be
>>> fixed and its value is taken from the .prm file. Now let us say one
>>> changes the value of 'delta_t' in the function 'run()'.
>>> What will be the convenient way to replace old value of 'delta_t' by the
>>> new one and use it to obtain current time etc
>>> using the class 'Time'.
>>>
>>> I shall be thankful if someone can help me in this regard.
>>>
>>> Thank you,
>>>
>>> Regards,
>>> Anup.
>>>
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