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</o:shapelayout></xml><![endif]--></head><body lang=DE link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hi I am trying to generate a matrix(nxn) from 3 arrays(1D) which I have read from 3 single textfiles:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>PetscInt pcol[] (dimension of nz): points to the integer array of length nz that holds the column indices of the corresponding elements in pval<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>PetscInt prow[] (dimesion of n)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>PetscScalar pval[] (dimension of nz)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I tried this:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>MatSetValues(A,n,prow,nz,pcol,pval,INSERT_VALUES);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Can I insert the hole data into matrix A or should I loop over it?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Thanks Jürgen</span><span style='mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>