Initial commit

dataassim/math/numrec/f77_sources/sprsax.for

@@ -0,0 +1,13 @@
+      SUBROUTINE sprsax(sa,ija,x,b,n)
+      INTEGER n,ija(*)
+      REAL b(n),sa(*),x(n)
+      INTEGER i,k
+      if (ija(1).ne.n+2) pause 'mismatched vector and matrix in sprsax'
+      do 12 i=1,n
+        b(i)=sa(i)*x(i)
+        do 11 k=ija(i),ija(i+1)-1
+          b(i)=b(i)+sa(k)*x(ija(k))
+11      continue
+12    continue
+      return
+      END