Thank you for your reply Ronald, I'm including the code I'm using just in case I did something wrong... class MatrixAlgorithm3D { public: ///////////////////////////////////////////////// //in an other class I have a utility function that gets the maximum values for every z vector in the array //and returns the resulting plane of values static array_type2D_ref maxPlan(array_type3D_const_ref matrix) { array_type2D resultMatrix(boost::extents[matrix.shape()[0]][matrix.shape()[1]]); array_type3D_const_ref::index_gen indices; for (unsigned int x = 0; x < matrix.shape()[0]; x++) { for (unsigned int y = 0; y < matrix.shape()[1]; y++) { // get the z vector for these coordinates array_type3D_const_ref::const_array_view<1>::type dimensionZmatrix = matrix[ indices[x][y][range()] ]; resultMatrix[x][y] = std::max_element(dimensionZmatrix.begin(), dimensionZmatrix.end()); } } return resultMatrix; } ///////////////////////////////////////////////// } typedef boost::multi_array < double, 3 > array_type3D; typedef boost::const_multi_array_ref < double, 3 > array_type3D_const_ref; typedef boost::multi_array < double, 2 > array_type2D; typedef boost::multi_array_ref < double, 2 > array_type2D_ref; int main(void) { array_type3D matrix(boost::extents[775][775][100]); // lets say I initialise it this way (I usually get the values from a flat file) for (unsigned int x = 0; x < 775; x++) { for (unsigned int y = 0; y < 775; y++) { for (unsigned int z = 0; z < 100; z++) { matrix[x][y][z] = avalue; } } } // then I call the function in my main program array_type2D a= MatrixAlgorithm3D::maxPlan(matrix); // should I use an array_type2D_ref for the return value instead? // then I write the results to a flat file ... return 0; } Ronald Garcia wrote:

Hello Sebastien,

Ideally, you should be able to work with an array of doubles, rather than an array of pointers to double. I can create an multi_array with the dimensions you mention.

To answer your questions, multi_array uses a standard library allocator to allocate a contiguous block of memory in which to hold the array data. I'm afraid I do not know why you cannot exceed these limits.

ron

...

I'm currently using multi_array to represent 3D matrices of doubles, I was wondering which would be the best use since the array has to hold a very large amount of data. I' currently testing whith a multi_array of 800x800x100 to hold double or pointers to double and I have memory problems. When I declare the multi_array whith pointers to doubles I can usually go up to 775x775x100 without problems but when I try the same thing with a multi_array of doubles I get a bad alloc error. My real needs for the moment are for a multi_array of 800x600x57 but I will need bigger storage capacity in the near future, what are your sugesstions.

Is the multi_array a pointer itself? How is memory management handled? How can go beyond these limits?

-- Sébastien Fortier

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-- Sébastien Fortier