Modifying stiffness matrix and rhs vector to allow for fixed displacements - Code Answer

Question 1

What does the ‘for iv = 1 : nvfix;’ loop consist of?

Answer 1

for id = 1 : ndofn;
if ifpre(iv, id) ≅ 0;
ig = (nofix (iv) - 1) * ndofn + id;
for i = 1 : ntotv;
rhsmod(i) = rhsmod(i) - presc(iv, id) * gstif(i, ig);
gstifmod(ig, i) = 0.0; gstifmod(i, ig) = 0.0;
end
gstifmod(ig, ig) = gstif(ig, ig);
end
end

Question 2

What is the for loop following the previous question?

Answer 2

for iv = 1 : nvfix;
     for id = 1 : ndofn;
          if ifpre(iv, id) ≅ 0;
             ig = (nofix (iv) - 1) * ndofn + id;
             rhsmod(ig) = presc(iv, id) * gstif(ig, ig);
          end
      end
end