Re: [Boost-users] [multi_array] how to modify the dimension of an array?

From: r0d (rpons_at_[hidden])
Date: 2008-05-31 08:12:19

everweb wrote:
> 
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> r0d wrote:
>> Hello everybody,
>> 
>> i'm looking for the best way to modify the dimensions of an array. For
>> example, i got this one:
>> 
>> boost::multi_array<int, 2> array ( boost::extents[3][3] );
>> 
>> and i want to change it in an array of 5 dimensions.
>> 
>> Now, what i'm doing is to create a new array of 5 dimensions and copying
>> the
>> first one into it, then delete the first one. But i'm sure that a more
>> efficient way exists. No?
> 
> use resize() - see below
> 
> 
> TEST(multi_array)
>     {
>     boost::multi_array<int, 2> myArray ( boost::extents[3][3] );
> 
>     int values = 0;
>     for(boost::multi_array<int, 2>::index i = 0; i != 3; ++i)
>         {
>         for(boost::multi_array<int, 2>::index j = 0; j != 3; ++j)
>             {
>             myArray[i][j] = values++;
>             }
>         }
> 
>     // Verify values
>     int verify1 = 0;
>     for(boost::multi_array<int, 2>::index i = 0; i != 3; ++i)
>         {
>         for(boost::multi_array<int, 2>::index j = 0; j != 3; ++j)
>             {
>             CHECK_EQUAL(myArray[i][j],verify1++);
>             }
>         }
>     myArray.resize(boost::extents[5][5]);
> 
>     //continue setting 'values' in the newly added array space
>     for(boost::multi_array<int, 2>::index i = 3; i != 5; ++i)
>         {
>         for(boost::multi_array<int, 2>::index j = 3; j != 5; ++j)
>             {
>             myArray[i][j] = values++;
>             }
>         }
> 
>     //check the original data is still there
>     int verify2 = 0;
>     for(boost::multi_array<int, 2>::index i = 0; i != 3; ++i)
>         {
>         for(boost::multi_array<int, 2>::index j = 0; j != 3; ++j)
>             {
>             CHECK_EQUAL(myArray[i][j],verify2++);
>             }
>         }
> 
>     //check that the new array space has correct values
>     for(boost::multi_array<int, 2>::index i = 3; i != 5; ++i)
>         {
>         for(boost::multi_array<int, 2>::index j = 3; j != 5; ++j)
>             {
>             CHECK_EQUAL(myArray[i][j],verify1++);
>             }
>         }
> 
> 
>     }
> 
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> 

Thank you everweb,

but that's not what i want to do. Surely i expained badly my problem (my
english is too bad).

I want to change the number of dimensions of the array. For example, i got
an array:
boost::multi_array<int, 2>
and i want to change it in
boost::multi_array<int, 5>

Is it possible to di it easyly?

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