org.mitre.poorMan.javaTiming

Interface DerivedComputation

public interface DerivedComputation

A metric that is computed from something in your application, including stop watches.

The metric is reported when Timing.dumpTimings() is called. The metric can be registered with Timing.registerDerivedComputation(). Below is an example in which the effective CPU throughput for computing an FFT is calculated based on the size of the FFT and the amount of time it took on average to compute it.

import static java.lang.Math.log;

final public class LoopTimes {
        public static StopWatch internalLoopTiming =
                Timing
                        .createAndRegisterStatistic("internal loop time")
                        .suppressIfValueIsZero();

        public static int iter;
        public static int nFFT;

        public static DerivedComputation internalGflops;

        public static final Double ZERO = new Double(0.0);

        static {
                Timing.stripBaseName("org.mitre");

                Timing.registerDerivedComputation("gflops (internal)",
                        internalGflops=new DerivedComputation(){

                        @Override
                        public String getComputedString() {
                                Number val = getComputedNumber();
                                if (val == ZERO) return null;
                                return val.toString() + " Gflops";
                        }

                        @Override
                        public Number getComputedNumber() {
                                if (internalLoopTiming.getCount() == 0){
                                        return ZERO;
                                }
                                else {
                                        double mx = (int)(log(nFFT)/log(2)+0.001);
                                        double time = internalLoopTiming.getCumulative();
                                        double gflops = (5.0 * mx  * nFFT *  iter)/(time);
                                        return new Double(gflops);
                                }
                        }
                });
        }

}

 

Version:

1.1

Author:

Nazario Irizarry

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Number	getComputedNumber() This is NOT called when timings are dumped.
java.lang.String	getComputedString() This is called when timings are dumped.

Method Detail

getComputedString

java.lang.String getComputedString()

This is called when timings are dumped. If the computation does not apply just return null.

Returns:

null if computation does not apply.

getComputedNumber

java.lang.Number getComputedNumber()

This is NOT called when timings are dumped. It exists as a way to query your specific derrived computation for a value if you need it.

Returns:

null if computation does not apply.