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Posted to dev@commons.apache.org by Gilles Sadowski <gi...@harfang.homelinux.org> on 2011/09/07 01:04:59 UTC
Re: svn commit: r1165846 [2/2] -
/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Hello.
> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
> ==============================================================================
> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
> @@ -74,31 +74,6147 @@ public class FastMath {
> /** Napier's constant e, base of the natural logarithm. */
> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
>
> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
> +
> /** Exponential evaluated at integer values,
> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
> */
> - private static final double EXP_INT_TABLE_A[] = new double[1500];
> + private static final double EXP_INT_TABLE_A[] =
> + {
> + +0.0d,
> + Double.NaN,
[More than 6000 lines stripped.]
Wouldn't it be advantageous to store those tabulated data in separate
Java files? E.g.
---
class ExpIntTables {
static final double[] A = {
// Very long table.
};
static final double[] B = {
// ...
};
---
And in "FastMath.java":
---
public class FastMath {
private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
}
---
Gilles
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Re: svn commit: r1165846 [2/2] - /commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Posted by sebb <se...@gmail.com>.
On 7 September 2011 12:07, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> On Wed, Sep 07, 2011 at 11:22:24AM +0100, sebb wrote:
>> On 7 September 2011 10:46, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
>> > On Wed, Sep 07, 2011 at 12:42:06AM +0100, sebb wrote:
>> >> On 7 September 2011 00:04, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
>> >> > Hello.
>> >> >
>> >> >> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
>> >> >> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
>> >> >> ==============================================================================
>> >> >> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
>> >> >> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
>> >> >> @@ -74,31 +74,6147 @@ public class FastMath {
>> >> >> /** Napier's constant e, base of the natural logarithm. */
>> >> >> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
>> >> >>
>> >> >> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
>> >> >> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
>> >> >> +
>> >> >> /** Exponential evaluated at integer values,
>> >> >> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
>> >> >> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
>> >> >> */
>> >> >> - private static final double EXP_INT_TABLE_A[] = new double[1500];
>> >> >> + private static final double EXP_INT_TABLE_A[] =
>> >> >> + {
>> >> >> + +0.0d,
>> >> >> + Double.NaN,
>> >> >
>> >> > [More than 6000 lines stripped.]
>> >> >
>> >> > Wouldn't it be advantageous to store those tabulated data in separate
>> >> > Java files? E.g.
>> >> > ---
>> >> > class ExpIntTables {
>> >> > static final double[] A = {
>> >> > // Very long table.
>> >> > };
>> >> > static final double[] B = {
>> >> > // ...
>> >> > };
>> >> > ---
>> >> >
>> >> > And in "FastMath.java":
>> >> > ---
>> >> > public class FastMath {
>> >> > private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
>> >> > private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
>> >> > }
>> >> > ---
>> >>
>> >> That would be possible, but would require the tables to be
>> >> non-private, increasing the theoretical risk of accidental changes.
>> >
>> > I know, but having "package" access level reduces the risk to our own
>> > mistakes, similar to any bug we can introduce when writing code.
>>
>> Except that there are now many more files that may need to be debugged.
>
> I'm not sure I understand. Once the tables are generated, you put them in
> their file and those data files need not be touched anymore.
I was referring to potential corruption of tables by other classes in
the same package.
>>
>> > One can also assumes that the tables will need much less changes (if
>> > at all) than actual code in "FastMath.java"; so having them in separate
>> > files could reduce the risk of messing with them... And of course, there is
>> > the practical advantage of not having to load/scroll 6000+ lines in orde to
>> > have a look at the code.
>>
>> We could move the tables and disabled setup code to the end of the source file.
>
> I don't remember the exact setup, but I once run into a source code file
> size problem by putting a lot of tables (as arrays) within the same Java
> file. It was solved by separating them out in several files...
> So, here one could imagine adding more and more tables (or adding more
> entries to the existing ones) until this will occur.
If it occurs we can fix the problem.
The current change has added a few constants and some methods, but the
number of tables and their contents are deliberately the same.
>>
>> Some of the setup code could be moved into a separate class - e.g. the
>> slowExp, slowSin and SlowCos methods use the FACT table, which is not
>> needed elsewhere.
>>
>> > By the way, how much faster is now the first use of a method from
>> > "FastMath"?
>>
>> Not checked. Perhaps the OP of the JIRA will be able to help there.
>>
>> That probably needs to be the next step.
>
> If the benefit is not significant, I'd rather have the previous setup.
That's currently fairly easy to revert.
But it was necessary to make the change in order to test it.
>
> Gilles
>
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>
>
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Re: svn commit: r1165846 [2/2] -
/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Posted by Gilles Sadowski <gi...@harfang.homelinux.org>.
On Wed, Sep 07, 2011 at 11:22:24AM +0100, sebb wrote:
> On 7 September 2011 10:46, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> > On Wed, Sep 07, 2011 at 12:42:06AM +0100, sebb wrote:
> >> On 7 September 2011 00:04, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> >> > Hello.
> >> >
> >> >> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
> >> >> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
> >> >> ==============================================================================
> >> >> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
> >> >> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
> >> >> @@ -74,31 +74,6147 @@ public class FastMath {
> >> >> /** Napier's constant e, base of the natural logarithm. */
> >> >> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
> >> >>
> >> >> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
> >> >> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
> >> >> +
> >> >> /** Exponential evaluated at integer values,
> >> >> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
> >> >> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
> >> >> */
> >> >> - private static final double EXP_INT_TABLE_A[] = new double[1500];
> >> >> + private static final double EXP_INT_TABLE_A[] =
> >> >> + {
> >> >> + +0.0d,
> >> >> + Double.NaN,
> >> >
> >> > [More than 6000 lines stripped.]
> >> >
> >> > Wouldn't it be advantageous to store those tabulated data in separate
> >> > Java files? E.g.
> >> > ---
> >> > class ExpIntTables {
> >> > static final double[] A = {
> >> > // Very long table.
> >> > };
> >> > static final double[] B = {
> >> > // ...
> >> > };
> >> > ---
> >> >
> >> > And in "FastMath.java":
> >> > ---
> >> > public class FastMath {
> >> > private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
> >> > private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
> >> > }
> >> > ---
> >>
> >> That would be possible, but would require the tables to be
> >> non-private, increasing the theoretical risk of accidental changes.
> >
> > I know, but having "package" access level reduces the risk to our own
> > mistakes, similar to any bug we can introduce when writing code.
>
> Except that there are now many more files that may need to be debugged.
I'm not sure I understand. Once the tables are generated, you put them in
their file and those data files need not be touched anymore.
>
> > One can also assumes that the tables will need much less changes (if
> > at all) than actual code in "FastMath.java"; so having them in separate
> > files could reduce the risk of messing with them... And of course, there is
> > the practical advantage of not having to load/scroll 6000+ lines in orde to
> > have a look at the code.
>
> We could move the tables and disabled setup code to the end of the source file.
I don't remember the exact setup, but I once run into a source code file
size problem by putting a lot of tables (as arrays) within the same Java
file. It was solved by separating them out in several files...
So, here one could imagine adding more and more tables (or adding more
entries to the existing ones) until this will occur.
>
> Some of the setup code could be moved into a separate class - e.g. the
> slowExp, slowSin and SlowCos methods use the FACT table, which is not
> needed elsewhere.
>
> > By the way, how much faster is now the first use of a method from
> > "FastMath"?
>
> Not checked. Perhaps the OP of the JIRA will be able to help there.
>
> That probably needs to be the next step.
If the benefit is not significant, I'd rather have the previous setup.
Gilles
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Re: svn commit: r1165846 [2/2] - /commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Posted by sebb <se...@gmail.com>.
On 7 September 2011 10:46, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> On Wed, Sep 07, 2011 at 12:42:06AM +0100, sebb wrote:
>> On 7 September 2011 00:04, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
>> > Hello.
>> >
>> >> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
>> >> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
>> >> ==============================================================================
>> >> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
>> >> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
>> >> @@ -74,31 +74,6147 @@ public class FastMath {
>> >> /** Napier's constant e, base of the natural logarithm. */
>> >> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
>> >>
>> >> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
>> >> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
>> >> +
>> >> /** Exponential evaluated at integer values,
>> >> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
>> >> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
>> >> */
>> >> - private static final double EXP_INT_TABLE_A[] = new double[1500];
>> >> + private static final double EXP_INT_TABLE_A[] =
>> >> + {
>> >> + +0.0d,
>> >> + Double.NaN,
>> >
>> > [More than 6000 lines stripped.]
>> >
>> > Wouldn't it be advantageous to store those tabulated data in separate
>> > Java files? E.g.
>> > ---
>> > class ExpIntTables {
>> > static final double[] A = {
>> > // Very long table.
>> > };
>> > static final double[] B = {
>> > // ...
>> > };
>> > ---
>> >
>> > And in "FastMath.java":
>> > ---
>> > public class FastMath {
>> > private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
>> > private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
>> > }
>> > ---
>>
>> That would be possible, but would require the tables to be
>> non-private, increasing the theoretical risk of accidental changes.
>
> I know, but having "package" access level reduces the risk to our own
> mistakes, similar to any bug we can introduce when writing code.
Except that there are now many more files that may need to be debugged.
> One can also assumes that the tables will need much less changes (if
> at all) than actual code in "FastMath.java"; so having them in separate
> files could reduce the risk of messing with them... And of course, there is
> the practical advantage of not having to load/scroll 6000+ lines in orde to
> have a look at the code.
We could move the tables and disabled setup code to the end of the source file.
Some of the setup code could be moved into a separate class - e.g. the
slowExp, slowSin and SlowCos methods use the FACT table, which is not
needed elsewhere.
> By the way, how much faster is now the first use of a method from
> "FastMath"?
Not checked. Perhaps the OP of the JIRA will be able to help there.
That probably needs to be the next step.
>
> Regards,
> Gilles
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
> For additional commands, e-mail: dev-help@commons.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
For additional commands, e-mail: dev-help@commons.apache.org
Re: svn commit: r1165846 [2/2] -
/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Posted by Gilles Sadowski <gi...@harfang.homelinux.org>.
On Wed, Sep 07, 2011 at 12:42:06AM +0100, sebb wrote:
> On 7 September 2011 00:04, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> > Hello.
> >
> >> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
> >> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
> >> ==============================================================================
> >> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
> >> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
> >> @@ -74,31 +74,6147 @@ public class FastMath {
> >> /** Napier's constant e, base of the natural logarithm. */
> >> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
> >>
> >> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
> >> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
> >> +
> >> /** Exponential evaluated at integer values,
> >> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
> >> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
> >> */
> >> - private static final double EXP_INT_TABLE_A[] = new double[1500];
> >> + private static final double EXP_INT_TABLE_A[] =
> >> + {
> >> + +0.0d,
> >> + Double.NaN,
> >
> > [More than 6000 lines stripped.]
> >
> > Wouldn't it be advantageous to store those tabulated data in separate
> > Java files? E.g.
> > ---
> > class ExpIntTables {
> > static final double[] A = {
> > // Very long table.
> > };
> > static final double[] B = {
> > // ...
> > };
> > ---
> >
> > And in "FastMath.java":
> > ---
> > public class FastMath {
> > private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
> > private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
> > }
> > ---
>
> That would be possible, but would require the tables to be
> non-private, increasing the theoretical risk of accidental changes.
I know, but having "package" access level reduces the risk to our own
mistakes, similar to any bug we can introduce when writing code.
One can also assumes that the tables will need much less changes (if
at all) than actual code in "FastMath.java"; so having them in separate
files could reduce the risk of messing with them... And of course, there is
the practical advantage of not having to load/scroll 6000+ lines in orde to
have a look at the code.
By the way, how much faster is now the first use of a method from
"FastMath"?
Regards,
Gilles
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Re: svn commit: r1165846 [2/2] - /commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
Posted by sebb <se...@gmail.com>.
On 7 September 2011 00:04, Gilles Sadowski <gi...@harfang.homelinux.org> wrote:
> Hello.
>
>> Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java
>> URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java?rev=1165846&r1=1165845&r2=1165846&view=diff
>> ==============================================================================
>> --- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java (original)
>> +++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/FastMath.java Tue Sep 6 21:06:58 2011
>> @@ -74,31 +74,6147 @@ public class FastMath {
>> /** Napier's constant e, base of the natural logarithm. */
>> public static final double E = 2850325.0 / 1048576.0 + 8.254840070411028747e-8;
>>
>> + private static final int EXP_INT_TABLE_MAX_INDEX = 750;
>> + private static final int EXP_INT_TABLE_LEN = EXP_INT_TABLE_MAX_INDEX * 2;
>> +
>> /** Exponential evaluated at integer values,
>> - * exp(x) = expIntTableA[x + 750] + expIntTableB[x+750].
>> + * exp(x) = expIntTableA[x + EXP_INT_TABLE_MAX_INDEX] + expIntTableB[x+EXP_INT_TABLE_MAX_INDEX].
>> */
>> - private static final double EXP_INT_TABLE_A[] = new double[1500];
>> + private static final double EXP_INT_TABLE_A[] =
>> + {
>> + +0.0d,
>> + Double.NaN,
>
> [More than 6000 lines stripped.]
>
> Wouldn't it be advantageous to store those tabulated data in separate
> Java files? E.g.
> ---
> class ExpIntTables {
> static final double[] A = {
> // Very long table.
> };
> static final double[] B = {
> // ...
> };
> ---
>
> And in "FastMath.java":
> ---
> public class FastMath {
> private static final double[] EXP_INT_TABLE_A = ExpIntTables.A;
> private static final double[] EXP_INT_TABLE_B = ExpIntTables.B;
> }
> ---
That would be possible, but would require the tables to be
non-private, increasing the theoretical risk of accidental changes.
>
> Gilles
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
> For additional commands, e-mail: dev-help@commons.apache.org
>
>
---------------------------------------------------------------------
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