sheet3

sheet3/7/.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+    "files.associations": {
+        "ostream": "cpp",
+        "iostream": "cpp"
+    }
+}

sheet3/7/Makefile

@@ -0,0 +1,33 @@
+#
+# use GNU-Compiler tools
+COMPILER=GCC_
+# alternatively from the shell
+# export COMPILER=GCC_
+# or, alternatively from the shell
+# make COMPILER=GCC_
+
+# use Intel compilers
+#COMPILER=ICC_
+
+# use PGI compilers
+# COMPILER=PGI_
+
+
+
+SOURCES = main.cpp 
+OBJECTS = $(SOURCES:.cpp=.o)
+
+PROGRAM	= main.${COMPILER}
+
+# uncomment the next to lines for debugging and detailed performance analysis
+CXXFLAGS += -g
+LINKFLAGS += -g
+# do not use -pg with PGI compilers
+
+ifndef COMPILER
+  COMPILER=GCC_
+endif
+
+include ../${COMPILER}default.mk
+$(PROGRAM): $(OBJECTS)
+	$(CXX) $(CXXFLAGS) $(OBJECTS) -llapacke -lopenblas -o $(PROGRAM)

sheet3/7/main.cpp

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+#include <cassert>
+#include <chrono>           // timing
+#include <cmath>            // sqrt()
+#include <cstdlib>          // atoi()
+#include <cstring>          // strncmp()
+#include <ctime>
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <lapacke.h>
+
+using namespace std;
+using namespace std::chrono;  // timing
+
+int main()
+{   
+    unsigned int n= 10;
+    unsigned int nhrs = 1;
+
+    vector<double> M(n*n,4.0);
+   
+    for(unsigned int i=0; i<n; i++)
+    {
+        for(unsigned int j=0; j<n; j++)
+        {
+            if(i!=j)
+            {
+                double diff = i-j;
+                M[i*n+j] = 1.0/(diff*diff);
+            }
+        }
+
+        
+    }
+
+    
+
+
+    vector<int> ipiv(n); //pivots
+    LAPACKE_dgetrf(LAPACK_ROW_MAJOR,n,n, M.data(),n,ipiv.data());  //M=PLU 
+
+
+    unsigned int runtimes[] = {1,2,4,8,16,32};
+
+    for(unsigned int i=0; i < 6;i++)
+    {
+        nhrs = runtimes[i];
+         vector<double> b(n*nhrs,0.0);
+        for (unsigned int j=0; j<n; j++)
+        {
+            for (unsigned int k=0; k<nhrs; k++)
+            {
+                b[j*nhrs+k] = j*nhrs+k;
+            }
+        } 
+        LAPACKE_dgetrs(LAPACK_ROW_MAJOR,'N',n,nhrs,M.data(),n,ipiv.data(),b.data(),nhrs);
+    }
+
+    
+    
+
+
+
+
+    return 0;
+
+    
+}