template error

[Adam Coutee]

Hello,

I am trying to compile some code that includes third party header files
(part of a library). I keep getting an error on the templates they've
defined. An example error follows:

"/usr/local/SensAble/GHOST/v31/include/gstGenericMatri x.h", line 115:
error(1424):
constant "DIMM" is not used in declaring the parameter types of
function template "gstGenericMatr ix::mulPointMat rix"
template <class PT1, class PT2, class MAT, int DIMM, int DIMN>

The code excerpt that generates this error is:

template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
inline void mulPointMatrix( PT1 & res,
const PT2 & p,
const MAT & m)
{
for (int i = 0; i < DIMN; ++i)
{
res[i] = 0;
for (int j = 0; j < DIMM; ++j)
{
res[i] += p[j] * m[j][i];
}
}
}

Does anyone know what the problem is? As mentioned, this is a header file
for a third-party library (that I don't have source code for). Apparently,
they built their applications with MIPSpro 7.3. I am using MIPSpro 7.2.1 on
an Octane running Irix 6.5.19f. Is this something that is allowed in MIPSpro
7.3, but not MIPSpro 7.2.1?

Thanks for any help,
Adam

[Alf P. Steinbach]

Re: template error

On Tue, 19 Aug 2003 12:53:18 -0400, "Adam Coutee" <gt5414d@prism. gatech.edu> wrote:
[color=blue]
>I am trying to compile some code that includes third party header files
>(part of a library). I keep getting an error on the templates they've
>defined. An example error follows:
>
>"/usr/local/SensAble/GHOST/v31/include/gstGenericMatri x.h", line 115:
>error(1424):
> constant "DIMM" is not used in declaring the parameter types of
> function template "gstGenericMatr ix::mulPointMat rix"
> template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
>
>The code excerpt that generates this error is:
>
>template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
>inline void mulPointMatrix( PT1 & res,
> const PT2 & p,
> const MAT & m)
>{
> for (int i = 0; i < DIMN; ++i)
> {
> res[i] = 0;
> for (int j = 0; j < DIMM; ++j)
> {
> res[i] += p[j] * m[j][i];
> }
> }
>}
>
>Does anyone know what the problem is?[/color]

That the compiler requires all template parameters to be used somehow
in the function's signature (because the compiler says so).

One solution could be to introduce dummy arguments, like so:


inline void mulPointMatrix(
PT1& res,
PT2 const& p,
MAT const& m,
int dummy1 = DIMM,
int dummy2 = DIMN
)


or perhaps


inline void mulPointMatrix(
PT1& res,
PT2 const& p,
MAT const& m,
int dummy1[DIMM] = 0,
int dummy2[DIMN] = 0
)


Another solution, to use a better compiler.

A third solution, not incompatible with the second, to use a better
library... ;-)

[Ron Natalie]

Re: template error


"Alf P. Steinbach" <alfps@start.no > wrote in message news:3f4257b3.4 26991593@News.C IS.DFN.DE...
[color=blue]
> inline void mulPointMatrix(
> PT1& res,
> PT2 const& p,
> MAT const& m,
> int dummy1 = DIMM,
> int dummy2 = DIMN
> )[/color]
I don't think this one will work. If the compiler relies on the function signature
to differentiate the template specializations , then it still fails.
[color=blue]
> inline void mulPointMatrix(
> PT1& res,
> PT2 const& p,
> MAT const& m,
> int dummy1[DIMM] = 0,
> int dummy2[DIMN] = 0
> )[/color]

I don't think this will work either, the arrays are converted to int* to form the function
type.

[Alf P. Steinbach]

Re: template error

On Tue, 19 Aug 2003 13:23:58 -0400, "Ron Natalie" <ron@sensor.com > wrote:
[color=blue]
>
>"Alf P. Steinbach" <alfps@start.no > wrote in message news:3f4257b3.4 26991593@News.C IS.DFN.DE...
>[color=green]
>> inline void mulPointMatrix(
>> PT1& res,
>> PT2 const& p,
>> MAT const& m,
>> int dummy1 = DIMM,
>> int dummy2 = DIMN
>> )[/color]
>I don't think this one will work. If the compiler relies on the function signature
>to differentiate the template specializations , then it still fails.
>[color=green]
>> inline void mulPointMatrix(
>> PT1& res,
>> PT2 const& p,
>> MAT const& m,
>> int dummy1[DIMM] = 0,
>> int dummy2[DIMN] = 0
>> )[/color]
>
>I don't think this will work either, the arrays are converted to int* to form the function
>type.[/color]

Well, what "used" means obviously depends on the (erronous) compiler.

But how about


template< int N >
struct Dummy
{
Dummy( int ) {}
};

template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
inline void mulPointMatrix(
PT1& res,
PT2 const& p,
MAT const& m,
Dummy<DIMM> dummy1 = 0,
Dummy<DIMN> dummy2 = 0
)
{
}

?

Of course, the best solution for the OP would be to use both a better
compiler and a better library, if possible.

[Ron Natalie]

Re: template error


"Alf P. Steinbach" <alfps@start.no > wrote in message news:3f425f2f.4 28907203@News.C IS.DFN.DE...

[color=blue]
>
> Well, what "used" means obviously depends on the (erronous) compiler.
>
> But how about
>
>
> template< int N >
> struct Dummy
> {
> Dummy( int ) {}
> };
>
> template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
> inline void mulPointMatrix(
> PT1& res,
> PT2 const& p,
> MAT const& m,
> Dummy<DIMM> dummy1 = 0,
> Dummy<DIMN> dummy2 = 0
> )
> {
> }[/color]

That one looks better.
Another solution would be to wrap the function in a class that depends on the
template args.

[Alf P. Steinbach]

Re: template error

On Tue, 19 Aug 2003 13:36:16 -0400, "Ron Natalie" <ron@sensor.com > wrote:
[color=blue]
>
>"Alf P. Steinbach" <alfps@start.no > wrote in message news:3f425f2f.4 28907203@News.C IS.DFN.DE...
>
>[color=green]
>>
>> Well, what "used" means obviously depends on the (erronous) compiler.
>>
>> But how about
>>
>>
>> template< int N >
>> struct Dummy
>> {
>> Dummy( int ) {}
>> };
>>
>> template <class PT1, class PT2, class MAT, int DIMM, int DIMN>
>> inline void mulPointMatrix(
>> PT1& res,
>> PT2 const& p,
>> MAT const& m,
>> Dummy<DIMM> dummy1 = 0,
>> Dummy<DIMN> dummy2 = 0
>> )
>> {
>> }[/color]
>
>That one looks better.
>Another solution would be to wrap the function in a class that depends on the
>template args.[/color]

If the library can be redesigned then _much_ better solutions exist. Keeping
the "fixed size matrix type" idea the size should be deducible from the type.
Even better, if possible allow mixture of fixed-size and dynamic-size with
compile time checking where all necessary information is available (now that
is, I think, a nice design problem -- is it possible to do in a clean way?).

But the intent was to not require any changes to existing client code.

[Adam Coutee]

Re: template error


[color=blue]
>
> Of course, the best solution for the OP would be to use both a better
> compiler and a better library, if possible.
>[/color]

Thanks for all of the info guys...
Sadly enough, I can't get a better library (what I have is what I get). :(

However, it seems to me that you think a newer version of the compiler
(MIPSpro) may do the trick. Is this the case?

Thanks again,
Adam