handle empty matrices in broadcast

Author: sethigeet

src/broadcast.cpp

@@ -1,56 +1,60 @@
-#include <iostream>
 #include <omp.h>
-#include <vector>
+
+#include <iostream>
 #include <stdexcept>
+#include <vector>
 
 // Function to broadcast two matrices
-void broadcast(const std::vector<std::vector<int>>& A, std::vector<std::vector<int>>& B) {
-    size_t rowsA = A.size();
-    size_t colsA = A[0].size();
-    size_t rowsB = B.size();
-    size_t colsB = B[0].size();
-
-    if (rowsA != rowsB && rowsB != 1) {
-        throw std::invalid_argument("Incompatible dimensions for broadcasting");
-    }
-    if (colsA != colsB && colsB != 1) {
-        throw std::invalid_argument("Incompatible dimensions for broadcasting");
-    }
+void broadcast(const std::vector<std::vector<int>>& A,
+               std::vector<std::vector<int>>& B) {
+  size_t rowsA = A.size();
+  size_t colsA = A[0].size();
+  size_t rowsB = B.size();
+  size_t colsB = B[0].size();
 
-    if (rowsB == 1) {
-        B.resize(rowsA, B[0]);
-    }
-    if (colsB == 1) {
-        for (auto& row : B) {
-            row.resize(colsA, row[0]);
-        }
+  if (rowsA == 0 || colsA == 0 || rowsB == 0 || colsB == 0) {
+    throw std::invalid_argument("Empty matrix cannot be broadcasted");
+  }
+  if (rowsA != rowsB && rowsB != 1) {
+    throw std::invalid_argument("Incompatible dimensions for broadcasting");
+  }
+  if (colsA != colsB && colsB != 1) {
+    throw std::invalid_argument("Incompatible dimensions for broadcasting");
+  }
+
+  if (rowsB == 1) {
+    B.resize(rowsA, B[0]);
+  }
+  if (colsB == 1) {
+    for (auto& row : B) {
+      row.resize(colsA, row[0]);
     }
+  }
 
-   
-    #pragma omp parallel for
-    for (size_t i = 0; i < rowsA; i++) {
-        #pragma omp parallel for
-        for (size_t j = 0; j < colsA; j++) {
-            B[i][j] = A[i][j]+B[i][j];
-        }
+#pragma omp parallel for
+  for (size_t i = 0; i < rowsA; i++) {
+#pragma omp parallel for
+    for (size_t j = 0; j < colsA; j++) {
+      B[i][j] = A[i][j] + B[i][j];
     }
+  }
 }
 
 int main() {
-    std::vector<std::vector<int>> A = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
-    std::vector<std::vector<int>> B = {{1,2,3}}; // B has only one row
-
-    try {
-        broadcast(A, B);
-        for (const auto& row : B) {
-            for (const auto& elem : row) {
-                std::cout << elem << " ";
-            }
-            std::cout << std::endl;
-        }
-    } catch (const std::invalid_argument& e) {
-        std::cerr << "Error: " << e.what() << std::endl;
+  std::vector<std::vector<int>> A = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+  std::vector<std::vector<int>> B = {{1, 2, 3}};  // B has only one row
+
+  try {
+    broadcast(A, B);
+    for (const auto& row : B) {
+      for (const auto& elem : row) {
+        std::cout << elem << " ";
+      }
+      std::cout << std::endl;
     }
+  } catch (const std::invalid_argument& e) {
+    std::cerr << "Error: " << e.what() << std::endl;
+  }
 
-    return 0;
+  return 0;
 }