Consider the following excerpt from a program that is supposed to merge-sort a vector. The function worker() is called in all processes except process 0, the function mergeSort() is called from process 0 (and from the places described in this excerpt), the function mergeSortLocal() sorts the specified vector and the function mergeParts() merges two sorted adjacent vectors, given the pointer to the first element, the total length and the length of the first vector. Which of the following issues are present? Describe the changes needed to solve them.
A: the application can deadlock if the length of the vector is smaller than the number of MPI processes. B: the application can produce a wrong result if the input vector size is not a power of 2. C: some worker processes are not used if the number of processes is not a power of 2. D: the application can deadlock if the number of processes is not a power of 2.
Consider the following excerpt from a program that is supposed to compute the product of two non-zero polynomials. The function worker() is called in all processes except process 0, the function product() is called from process 0. The polynomials are represented with coefficient for degree 0 at index 0 in the vector. Which of the following issues are present if the output degree plus one is not a multiple of the number of MPI processes? Describe the changes needed to solve them.
A: the application can have memory corruption. B: the application can deadlock. C: some worker processes are not used. D: some coefficients are computed twice. E: some coefficients are not computed at all. F: some coefficients are computed incorrectly.