CPUTimeRef.cpp File Reference

Compute the reference CPU time with the finite volume solver. The output is the CPU time for 1 iteration. More...

#include "Carmen.h"

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Functions
double	CPUTimeRef (int iterations, int scales)
	Returns the time required by a finite volume computation using iterations iterations and scales scales. It is use to estimate the CPU time compression. More...

Detailed Description

Compute the reference CPU time with the finite volume solver. The output is the CPU time for 1 iteration.

Function Documentation

double CPUTimeRef	(	int	iterations,
		int	scales
	)

Returns the time required by a finite volume computation using iterations iterations and scales scales. It is use to estimate the CPU time compression.

Parameters

iterations	Number of iterations.
scales	Scales

Returns

double

{
    // --- Local variables ---------------------------------------------------

    int OldIterationNb=0;
    int OldScaleNb=0;
    real OldTimeStep=0.;
    bool ConstantTimeStepOld=ConstantTimeStep;

    double result=0.;

    Timer CPURef;
    FineMesh* MeshRef;

    // --- Execution ---------------------------------------------------------

    // Toggle on : Compute reference CPU time

    ComputeCPUTimeRef = true;

    // Toggle off : Constant time step

    ConstantTimeStep = true;

    // backup values of IterationNb and ScaleNb

    OldIterationNb  = IterationNb;
    OldScaleNb  = ScaleNb;
    OldTimeStep     = TimeStep;

    // use reference values
    IterationNb     = iterations;
    ScaleNb         = scales;
    TimeStep    = 0.;

    one_D=1; two_D=1;
    if (Dimension >= 2) one_D=1<<ScaleNb;
    if (Dimension == 3) two_D=1<<ScaleNb;

    // init mesh
    MeshRef = new FineMesh;

    // Iterate on time

    for (IterationNo = 1; IterationNo <= IterationNb; IterationNo++)
    {
        // start timer
        CPURef.start();

        // Compute time evolution
        TimeEvolution(MeshRef);

        // check CPU Time
        CPURef.check();

        // stop timer
        CPURef.stop();
    }

    // Compute CPUTimeRef
    result = CPURef.CPUTime();
    result *= 1./IterationNb;
    result *= 1<<(Dimension*(OldScaleNb-ScaleNb));

    // delete MeshRef
    delete MeshRef;

    // restore values of IterationNb and ScaleNb
    IterationNb = OldIterationNb;
    ScaleNb = OldScaleNb;
    TimeStep = OldTimeStep;
    IterationNo = 0;

    one_D=1; two_D=1;
    if (Dimension >= 2) one_D=1<<ScaleNb;
    if (Dimension == 3) two_D=1<<ScaleNb;

    // Toggle off : Compute reference CPU time

    ComputeCPUTimeRef = false;

    // Restore the value of ConstantTimeStep

    ConstantTimeStep = ConstantTimeStepOld;

    return result;
}

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