Now I have a vtkImageData (WxHxS) .I want to recontruct the cube to SxHxW
I think there is a mapping for the goal
NEW ORIGIN
(i,0,0) ⇒ (W-i,0,0)
(0,j,0) ⇒ (W,j,0)
(0,0,k) ⇒ (W,0,k)
so I try to setting the new diminsion and extent for the vtkImageData
m->SetDimensions(S, H, W);
m->SetSpacing(origin->GetSpacing()[2], origin->GetSpacing()[1], origin->GetSpacing()[0]);
for (int k = 0; k < W; k++)
for (int j = 0; j < H; j++)
for (int i = 0; i< S; i++)
{
ptr = (unsigned short *)m->GetScalarPointer(i, j, k);
ori = (unsigned short *)origin->GetScalarPointer(W - 1 - k, j, S -1- i);
*ptr = *ori;
}
//But it doesn't get the matter
//However, when I use the pixel method to copy origin data or upsidedow data, it is correct //like below
//copy the same structure
for (int k = 0; k < S; k++)
for (int j = 0; j < H; j++)
for (int i = 0; i< W; i++)
{
ori = (unsigned short*)origin->GetScalarPointer(i, j, k);
ptr = (unsigned short*)m->GetScalarPointer(i, j, k);
*ptr = *ori;
}
//upsiaedown
double val; int i = 0;
for (vtkIdType f = m->GetNumberOfPoints() - 1; f > -1; f--)
{
val =m->GetPointData()->GetScalars()->GetTuple1(f);
origin->GetPointData()->GetScalars()->SetTuple1(i, val);
i++;
}
correct cubic output
Briefly speaking, I want to get a new vtkImageData which is rotate (alone specify axis)
Related
This is a very simple program where the user inputs (x,y) coordinates and distance 'd' and the program has to find out the number of unrepeated coordinates from (x,y) to (x+d,y).
For eg: if input for one test case is: 4,9,2 then the unrepeated coordinates are (4,9),(5,9) and (6,9)(x=4,y=9,d=2). I have used a sorting algorithm as mentioned in the question (to keep track of multiple occurrences) however the program shows runtime error for test cases beyond 30. Is there any mistake in the code or is it an issue with my compiler?
For a detailed explanation of question: https://www.hackerearth.com/practice/algorithms/sorting/merge-sort/practice-problems/algorithm/missing-soldiers-december-easy-easy/
#include <stdio.h>
#include <stdlib.h>
int partition(int *arr, int p, int r) {
int x;
x = arr[r];
int tmp;
int i = p - 1;
for (int j = p; j <= r - 1; ++j) {
if (arr[j] <= x) {
i = i + 1;
tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;
}
}
tmp = arr[i + 1];
arr[i + 1] = arr[r];
arr[r] = tmp;
return (i + 1);
}
void quicksort(int *arr, int p, int r) {
int q;
if (p < r) {
q = partition(arr, p, r);
quicksort(arr, p, q - 1);
quicksort(arr, q + 1, r);
}
}
int count(int A[],int ct) {
int cnt = 0;
for (int i = 0; i < ct; ++i) {
if (A[i] != A[i + 1]) {
cnt++;
}
}
return cnt;
}
int main() {
int t;
scanf("%d", &t);
long int tmp, y, d;
int ct = 0;
int i = 0;
int x[1000];
int j = 0;
for (int l = 0; l < t; ++l) {
scanf("%d%d%d", &tmp, &y, &d);
ct = ct + d + 1; //this counts the total no of coordinates for each (x,y,d)
for (int i = 0; i <= d; ++i) {
x[j] = tmp + i; //storing all possible the x and x+d coordinates
j++;
}
}
int cnt;
int p = ct - 1;
quicksort(x, 0, p); //quicksort sorting
for (int l = 0; l < ct; ++l) {
printf("%d ", x[l]); //prints sorted array not necessary to question
}
cnt = count(x, ct); //counts the number of non-repeated vertices
printf("%d\n", cnt);
}
The problem was the bounds of the array int x[1000] is not enough for the data given below.
I'm relatively new to Thrust and I'm trying to perform a segmented scan. Here is my code, which you should be able to run as-is:
#include <thrust/host_vector.h>
#include <thrust/device_vector.h>
#include <thrust/execution_policy.h>
#include <chrono>
// Sequential scan for CPU
float* test_seqScan(float* in, int s, int m) {
float* out = new float[s * m];
for (unsigned int i = 0; i < s; i++) {
out[i * m] = 0;
}
for (unsigned int i = 0; i < s; i++) {
for (unsigned int j = 1; j < m; j++) {
out[i * m + j] = out[i * m + j - 1] + in[i * m + j - 1];
}
}
return out;
}
void test_sumScan(thrust::device_vector<float> dev_in, thrust::device_vector<int> dev_keys, int s, int m) {
// Allocate device memory for output
thrust::device_vector<float> dev_out(s * m);
thrust::exclusive_scan_by_key(thrust::device, dev_keys.begin(), dev_keys.end(), dev_in.begin(), dev_out.begin());
}
int main(){
int s = 100;
int m = 100000;
float* seq_in = new float[s * m];
for (int i = 0; i < s; i++) {
for (int j = 0; j < m; j++) {
seq_in[i * m + j] = j + 1;
}
}
thrust::host_vector<float> par_in(s * m);
for (int i = 0; i < s; i++) {
for (int j = 0; j < m; j++) {
par_in[i * m + j] = j + 1;
}
}
thrust::host_vector<int> keys(s * m);
for (int i = 0; i < s; i++) {
for (int j = 0; j < m; j++) {
keys[i * m + j] = i;
}
}
thrust::device_vector<float> dev_in = par_in;
thrust::device_vector<int> dev_keys = keys;
auto t1 = std::chrono::high_resolution_clock::now();
test_seqScan(seq_in, s, m);
auto t2 = std::chrono::high_resolution_clock::now();
auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>(t2 - t1).count();
std::cout << "Sequential duration: " << duration1 << "\n\n";
auto t3 = std::chrono::high_resolution_clock::now();
test_sumScan(dev_in, dev_keys, s, m);
auto t4 = std::chrono::high_resolution_clock::now();
auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>(t2 - t1).count();
std::cout << "Parallel duration: " << duration2 << "\n\n";
}
My issue is that both these snippets of code take exactly the same amount of time to run regardless of how small or large I set s and m. I assume that I'm doing something wrong, but I don't know what; can anyone point out the issue?
I am trying to use Malloc function to dynamically allocate memory but I also want to specify my data entry for operation rather than taking the user input.
I have found this code here which works fine, but I am working with a large data set and taking user input is not an option, so I want to keep using MALLOC but also define the data set.
like instead of following,
//Input Matrix1
for (i = 0; i < r1; i++)
for (j = 0; j < c1; j++)
scanf_s("%d", &mat1[i][j]);
I want something like
//mat1[2][2] = { {1,2},{2,3} }
to be inputed in the code
What would be the way to do it? I would really appreciate some advice. Thanks
#include<stdio.h>
#include<stdlib.h>
int main() {
int **mat1, **mat2, **res, i, j,k, r1, c1, r2, c2;
printf("\nEnter the Order of the First matrix...\n");
scanf_s("%d %d", &r1, &c1);
printf("\nEnter the Order of the Second matrix...\n");
scanf_s("%d %d", &r2, &c2);
if (c1 != r2) {
printf("Invalid Order of matrix");
exit(EXIT_SUCCESS);
}
mat1 = (int**)malloc(r1 * sizeof(int*));
for (i = 0; i < c1; i++)
mat1[i] = (int*)malloc(c1 * sizeof(int));
mat2 = (int**)malloc(r2 * sizeof(int*));
for (i = 0; i < c2; i++)
mat2[i] = (int*)malloc(c2 * sizeof(int));
res = (int**)calloc(r1, sizeof(int*));
for (i = 0; i < c2; i++)
res[i] = (int*)calloc(c2, sizeof(int));
/**/
//Input Matrix1
for (i = 0; i < r1; i++)
for (j = 0; j < c1; j++)
scanf_s("%d", &mat1[i][j]);
//Input Matrix2
for (i = 0; i < r2; i++)
for (j = 0; j < c2; j++)
scanf_s("%d", &mat2[i][j]);
//Printing Input Matrix 1 and 2
printf("\n Entered Matrix 1: \n");
for (i = 0; i < r1; i++) {
for (j = 0; j < c1; j++)
printf("%d ", mat1[i][j]);
printf("\n");
}
printf("\n Entered Matrix 2: \n");
for (i = 0; i < r2; i++) {
for (j = 0; j < c2; j++)
printf("%d ", mat2[i][j]);
printf("\n");
}
//int mat1[2][2] = { {1,2},{2,3} };
//int mat2[2][2] = { {1,3},{2,4} };
//Computation
//Multiplication
for (i = 0; i < r1; i++) {
for (j = 0; j < c2; j++) {
res[i][j] = 0;
for (k = 0; k < c1; k++)
res[i][j] += mat1[i][k] * mat2[k][j];
}
printf("\n");
}
printf("\nThe Multiplication of two matrix is\n");
for (i = 0; i < r1; i++) {
printf("\n");
for (j = 0; j < c2; j++)
printf("%d\t", res[i][j]);
}
printf("\n");
/* Addition
for(i=0;i<r1;i++)
for(j=0;j<c2;j++)
res[i][j]=mat1[i][j]+mat2[i][j];
printf("\nThe Addition of two matrix is\n");
for(i=0;i<r1;i++){
printf("\n");
for(j=0;j<c2;j++)
printf("%d\t",res[i][j]);
}
*/
return 0;
}
Please specify the format of your input data. Is it a csv file?
You can only specify data in the format int b[4] = {1, 2, 3, 4} when the size of b is fixed, i.e. known at compile time. But if all you matrices are known at compile time anyway, why bother doing dynamic allocation?
Also I cleaned up your code a bit:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define index(x, y, r) (x+r*y)
struct matrix {
int cols;
int rows;
double * data;
};
void print_mat(struct matrix * mat) {
int i, j;
for (i = 0; i < mat->rows; i++) {
for (j = 0; j < mat->cols; j++) {
printf("%f \t", mat->data[index(i, j, mat->rows)]);
}
printf("\n");
}
}
int mat_alloc(struct matrix *mat) {
mat->data = (double*)malloc(mat->rows*mat->cols*sizeof(double));
}
int read_mat(struct matrix *mat) {
int i, j;
for (i = 0; i < mat->rows; i++) {
for (j = 0; j < mat->cols; j++) {
scanf("%lf", &(mat->data[index(i, j, mat->rows)]));
}
}
}
int multiply(struct matrix * a, struct matrix * b, struct matrix * res) {
if(a->cols != b->rows){
printf("Matrix dimensions do not match!\n");
return 0;
}
res->rows = a->rows;
res->cols = b->cols;
mat_alloc(res);
memset(res->data, 0, res->cols*res->rows*sizeof(double));
int i, j, k;
for (i = 0; i < res->rows; i++) {
for (j = 0; j < res->cols; j++) {
for (k = 0; k < a->cols; k++) {
res->data[index(i, j, res->rows)] += a->data[index(i, k, a->rows)] * b->data[index(k, j, b->rows)];
}
}
}
}
int main() {
struct matrix mat1, mat2, res;
printf("\nEnter the Order of the First matrix...\n");
scanf("%d %d", &mat1.rows, &mat1.cols);
printf("\nEnter the Order of the Second matrix...\n");
scanf("%d %d", &mat2.rows, &mat2.cols);
mat_alloc(&mat1);
mat_alloc(&mat2);
read_mat(&mat1);
read_mat(&mat2);
printf("Scanned matrices: \n");
print_mat(&mat1);
printf("\n");
print_mat(&mat2);
printf("\n");
multiply(&mat1, &mat2, &res);
printf("Calculated result: \n");
print_mat(&res);
return 0;
}
i am clueless as to what is wrong with this piece of code.
its not working as expected.
its expected to display the shortest path from vertex 1 to N.
but its failing on a lot of cases.
one such case is
3 1
1 2 1
it shows the answer as
1 25 -1 3
which is wrong...
any help would be appreciated.
Thanks.
#include <iostream>
#include <cstdio>
#include <vector>
#include <list>
using namespace std;
struct Edge{
int I, W;
};
vector <int> dist;
vector <int> parent;
bool bellman_ford(const vector< vector <Edge> > &graph, int n){
dist[1] = 0;
parent[1] = 0;
for(int k = 1; k <= n-1; k++){
for(int i = 1; i <= n; i++){
int len = graph[i].size();
for(int j = 0; j < len; j++){
int v = graph[i][j].I;
int w = graph[i][j].W;
if(dist[v] > dist[i] + w){
dist[v] = dist[i] + w;
parent[v] = i;
}
}
}
}
for(int i = 1; i <= n; i++){
int len = graph[i].size();
for(int j = 0; j < len; j++){
int v = graph[i][j].I;
int w = graph[i][j].W;
if(dist[v] > dist[i] + w){
return false;
}
}
}
return true;
}
int main(void){
int n, m, x, y, w;
scanf("%d%d", &n, &m);
dist.resize(n+1, 10000000);
parent.resize(n+1, -1);
vector < vector <Edge> > graph (n+1, vector <Edge> (0)) ;
for(int i = 0; i < m; i++){
scanf("%d%d%d", &x, &y, &w);
Edge a, b;
a.I = y;
b.I = x;
a.W = b.W = w;
graph[x].push_back(a);
graph[y].push_back(b);
}
if(bellman_ford(graph, n)){
int k = n;
vector<int>ans;
ans.push_back(n);
while(parent[k] != 0){
ans.push_back(parent[k]);
k = parent[k];
}
for(int i = ans.size()-1; i >= 0; i--){
printf("%d ", ans[i]);
}
printf("\n");
}
}
For the input case 3 1 1 2 1 you have a graph of 3 vertices, but the graph has only a single edge (1->2):
(1)<~~>(2) (3)
so the vertex numbered 3 (n) is never reached. The parent node of 3 is set to initial value -1, your loop searches for 0. You have no check if there actually is a path from a source to its target or not at all. The output is correct until -1:
3 - target
-1 - target has no parent, the loop should stop
25 - *garbage* (UB)
1 - *garbage* (UB)
How does one go about sorting an array with the int contents {782, 40, 21}, using the Radix sort method, and utilizing bitwise shift ">>" and bitwise and "&" operators? How is this done using base 8 and 4?
Example base 256 radix sort for 32 bit integers. std::swap() could be replaced by any swap method.
typedef unsigned int uint32_t;
// a is input array, b is working array
uint32_t * RadixSort(uint32_t * a, uint32_t *b, size_t count)
{
size_t mIndex[4][256] = {0}; // count / index matrix
size_t i,j,m,n;
uint32_t u;
for(i = 0; i < count; i++){ // generate histograms
u = a[i];
for(j = 0; j < 4; j++){
mIndex[j][(size_t)(u & 0xff)]++;
u >>= 8;
}
}
for(j = 0; j < 4; j++){ // convert to indices
m = 0;
for(i = 0; i < 256; i++){
n = mIndex[j][i];
mIndex[j][i] = m;
m += n;
}
}
for(j = 0; j < 4; j++){ // radix sort
for(i = 0; i < count; i++){ // sort by current lsb
u = a[i];
m = (size_t)(u>>(j<<3))&0xff;
b[mIndex[j][m]++] = u;
}
std::swap(a, b); // swap ptrs
}
return(a);
}