allocation

问题 I'm currently trying to use the CUSPARSE library in order to speed up an HPCG implementation. However, it appears I'm making some kind of mistake during device data allocation. This is the code segment that results in CUSPARSE_STATUS_MAPPING_ERROR : int HPC_sparsemv( CRS_Matrix *A_crs_d, FP * x_d, FP * y_d) { FP alpha = 1.0f; FP beta = 0.0f; FP* vals = A_crs_d->vals; int* inds = A_crs_d->col_ind; int* row_ptr = A_crs_d->row_ptr; /*generate Matrix descriptor for SparseMV computation*/

问题 I know this question title looks scary, but it isn't. Sorry! Ok, so, what's the point of creating a one-time-only/unchangeable "variable"? Lets say I have one property called "name" in a Person object. const Person = { name: 'Luis Felipe Zaguini' }; Alright. So, it's incredibly common to see people doing this: let personName = Person.name; console.log(`I've written my name, and it is ${personName}.`); And that's it. In the majority of times that variable is used only once. Or, sometimes, it's

问题 I tried to add to my project rather limited functionality from the Boost library, namely allocating memory for small objects from a pool with the help of the 'pool_allocator' class, and discovered that I need to add to the project dependendencies to 4 debug static library files and to 4 release static library files. I.e. 8 library file dependencies are needed for a single line like this: boost::container::vector<int, boost::pool_allocator<int> > v; Is there a way to using these classes

问题 My task consists of two parts. First I have to create globbal char array of 100 elements, and insert some text to it using cin. Afterwards calculate amount of chars, and create dedicated array with the length of the inputted text. I was thinking about following solution : char[100]inputData; int main() { cin >> inputData >> endl; int length=0; for(int i=0; i<100; i++) { while(inputData[i] == "\0") { ++count; } } char c = new char[count]; Am I thinking good ? Second part of the task is to

问题 I'm still confused about the behaviour of std::vector::resize() . Consider the following code (see also type requirements for std::vector<type>) struct A { A() : X(0) { std::cerr<<" A::A(); this="<<this<<'\n'; } A(A const&) { assert(0); } // is required but doesn't fire in vector::resize int X; }; int main() { std::vector<A> a; a.resize(4); // would not compile without A::A(A const&) or A::A(A&&) } Without A::A(A const&) or A::A(A&&) , the line with a.resize(4); doesn't compile. However, that

问题 so I have a small problem whilst working with SQL and PHP. I have a sql db which has 4 tables namely, customers, requests, products and sellers. Now, each table contains self explanatory data. Such as customers tables lists the customers, ids, names, adresses, emails etc., products table has product id and the name, the requests table shows the request of products made by customers with the request id[pk], custID[fk from customer table], productid[fk in products table], quantites_requested,

问题 Can I get in C the program variables' types those existing in a specific memory segment at runtime. C Does not recognize the error in: int k=5; float s= 3.4; k=s; printf("%d", k); I am trying to change the variables' types at runtime. 回答1: C is a static type language, you can't change a variable's type. This code: int k=5; float s= 3.4; k=s; //type conversion didn't change k 's type, k is still of type int , all it does is to convert the float value ( 3.4f ) to an int (which is 3 ), and

问题 As I understand it, std::vector allocates/de-allocates all the memory it requires each time it's elements grows or shrinks, therefore pointer arithmetic can be used to iterate the vector elements. std::list on the other hand uses a double linked list, with each element pointing to the next and previous element. Assuming(possibly wrongly) that std::list allocates it's memory dynamically, so memory is allocated, if and when required, incrementally. How is std::list still able to offer pointer

问题 This is low-level memory question about how Java performs .add and .remove on an ArrayList or other types of lists. I would think that Java would have to do a reallocation of memory to append/remove items to a list, but it could be doing something I'm not thinking of to avoid this. Does anyone know? 回答1: If by "regular list" you mean java.util.List , that is an interface. It does not specify anything about whether or when any memory is allocated in association with adding or removing elements

问题 I have a MPI program for image processing (pgm file) in MPI C and I use Dynamic allocation for a 2D Array as follows. float **masterbuf; masterbuf = arralloc(sizeof(float), 2, M, N); When I use float masterbuf[M][N]; the image that the program gives looks fine. The problem is that when I use dynamic allocation the image loses some pixels in its left side. So these missing pixels create a black line. It's like the image has been shifted 2 pixels right. I don't do any other operations to the