parallel-processing

问题 The below program is a simple threaded program . For some reason which i am not able to figure , its getting stuck at infinite loop of both produce() and consume() methods simultaneously in both the threads. It produces the output for a few times and then there is no output at the console. So I presume its getting stuck at the loop. My question is , since the loop depends on the value of the flag valueSet of the same object of Item class , valueSet can't be both true and false at the same

问题 Parallel.For(0, Height, new ParallelOptions { MaxDegreeOfParallelism = 6 }, y => { int currentLine = y * BMPData.Stride; for (int x = 0; x < Width; x = x + BPX) { var b = pixels[currentLine + x]; var g = pixels[currentLine + x + 1]; var r = pixels[currentLine + x + 2]; int avg = (r + g + b) / 3; pixels[currentLine + x] = (byte)avg; pixels[currentLine + x + 1] = (byte)avg; pixels[currentLine + x + 2] = (byte)avg; } }); This is basically a parallel code where it turns bitmap data pixels into

问题 I have the following code:- extension Collection { // EZSE : A parralelized map for collections, operation is non blocking public func pmap<R>(_ each: (Self.Iterator.Element) -> R) -> [R?] { let indices = indicesArray() var res = [R?](repeating: nil, count: indices.count) DispatchQueue.concurrentPerform(iterations: indices.count) { (index) in let elementIndex = indices[index] res[index] = each(self[elementIndex]) } // Above code is non blocking so partial exec on most runs return res } ///

问题 I have the following code:- extension Collection { // EZSE : A parralelized map for collections, operation is non blocking public func pmap<R>(_ each: (Self.Iterator.Element) -> R) -> [R?] { let indices = indicesArray() var res = [R?](repeating: nil, count: indices.count) DispatchQueue.concurrentPerform(iterations: indices.count) { (index) in let elementIndex = indices[index] res[index] = each(self[elementIndex]) } // Above code is non blocking so partial exec on most runs return res } ///

问题 I have to solve a differential equations system many times, iterating over a parameter. For this, I run a loop over a list of the parameter, and store the solution (evaluated at an array of time values) for each parameter. So I have a 2D array in which I store solutions (each row is for a value of the parameter). Now, since any iteration has nothing to do with another one, I thought of doing this in parallel. Here is my code: using DifferentialEquations using SharedArrays using DelimitedFiles

问题 I have to solve a differential equations system many times, iterating over a parameter. For this, I run a loop over a list of the parameter, and store the solution (evaluated at an array of time values) for each parameter. So I have a 2D array in which I store solutions (each row is for a value of the parameter). Now, since any iteration has nothing to do with another one, I thought of doing this in parallel. Here is my code: using DifferentialEquations using SharedArrays using DelimitedFiles

问题 I have a requirement to fetch blob files from Azure storage, read through them, get the data and process it, and store it into a database. The number of data fetched from blob is high, i.e. around 40K records per file. There are 70 files like this in a folder. This is how I designed it: I use Parallel.Foreach on list of blob files with max parallelism 4. In each loop, I fetch stream a blob ( OpenRead method), read through it and fill a datatable. If the datatable size is 10000, I will call

问题 I have the following simple Cython function for a parallel reduction: # cython: boundscheck = False # cython: initializedcheck = False # cython: wraparound = False # cython: cdivision = True # cython: language_level = 3 from cython.parallel import parallel, prange cpdef double simple_reduction(int n, int num_threads): cdef int i cdef int sum = 0 for i in prange(n, nogil=True, num_threads=num_threads): sum += 1 return sum Which horrifyingly returns the following: In [3]: simple_reduction(n=10,

问题 I have the following simple Cython function for a parallel reduction: # cython: boundscheck = False # cython: initializedcheck = False # cython: wraparound = False # cython: cdivision = True # cython: language_level = 3 from cython.parallel import parallel, prange cpdef double simple_reduction(int n, int num_threads): cdef int i cdef int sum = 0 for i in prange(n, nogil=True, num_threads=num_threads): sum += 1 return sum Which horrifyingly returns the following: In [3]: simple_reduction(n=10,

问题 I have the following simple Cython function for a parallel reduction: # cython: boundscheck = False # cython: initializedcheck = False # cython: wraparound = False # cython: cdivision = True # cython: language_level = 3 from cython.parallel import parallel, prange cpdef double simple_reduction(int n, int num_threads): cdef int i cdef int sum = 0 for i in prange(n, nogil=True, num_threads=num_threads): sum += 1 return sum Which horrifyingly returns the following: In [3]: simple_reduction(n=10,