Re: [Boost-users] multi_array with large dimensions crashes

Hi Pierre, Sorry for the late reply. The code work now, thanks very much. But the programme crashes with a run-time error when the dimensions of the array are huge 500x500x500. This is probably due to the limitation of the 32 bit addrress space. Is there any other work around. I heard of creating arrays with strides and allocating them in different blocks of memory rather than in contiguos memory? Thanks again Jothy On Wed, Aug 24, 2011 at 6:25 PM, Pierre-Andre Noel < noel.pierre.andre@gmail.com> wrote:

Yes, 500, 300 and 400 were the example dimensions you used in your earlier message.

Did you got it to work?

Pierre-André

PS: This email was not sent to the whole list.

On Wed, Aug 24, 2011 at 11:55 AM, Jothy wrote:

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You mean 500,300,400 are the required dimesnions and xDim,yDim,zDim are site_type parameters.

So the code should be like below I guess for an array of [x][y][z]

array_ref_type::size_type xDim(x), yDim(y), zDim(z);

array_storage_type Storage(xDim*yDim*zDim); array_ref_type Array(&Storage.front(),boost::extents[xDim][yDim][zDim]);

Thanks

Jothy

On Wed, Aug 24, 2011 at 3:51 PM, Pierre-Andre Noel < noel.pierre.andre@gmail.com> wrote:

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I am not familiar with multi_array, but it seems that you are creating a >1GB object on the stack. This will almost always crash. Try creating it on the heap instead. Be prepared for std::bad_alloc.

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But how to do this? I am new to c++.

I suggest you to either 1. read on the operators "new" and "delete" or 2. use a std::vector to allocate the memory then use a boost::multi_array_ref to refer to it. Here's an example:

#include <vector> #include

int main() { typedef float data_type; typedef std::vector array_storage_type; typedef boost::multi_array_ref array_ref_type;

array_ref_type::size_type xDim(500), yDim(300), zDim(400); array_storage_type Storage(xDim*yDim*zDim); array_ref_type Array(&Storage.front(),boost::extents[xDim][yDim][zDim]); // You may now use Array as usual. }

Hope it helps,

Pierre-André Noël

On Wed, Aug 24, 2011 at 5:20 AM, Jothy wrote:

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Thanks for pointing this out.

But how to do this? I am new to c++.

Jothy

On Tue, Aug 23, 2011 at 10:42 PM, Juraj Ivančić < juraj.ivancic@gmail.com> wrote:

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On 23.8.2011. 12:18, Jothy wrote:

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Hi all,

I have just started to use boost libs. I am trying to create a large float array (mandatory for my purpose). it works fine till certain limit, but crashes above that. I think it about allocating memory in the stack.

My code is like this

typedefboost::multi_array<**float,3>array_type; typedefarray_type::indexindex; array_typeArray(boost::**extents[xDim][yDim][zDim]);//**500,300,400 for instance

Can some one help me to resolve this?

I am not familiar with multi_array, but it seems that you are creating a >1GB object on the stack. This will almost always crash. Try creating it on the heap instead. Be prepared for std::bad_alloc.

HTH

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