Initial commit

dataassim/math/numrec/f77_sources/dsprstx.for

@@ -0,0 +1,16 @@
+      SUBROUTINE dsprstx(sa,ija,x,b,n)
+      INTEGER n,ija(*)
+      DOUBLE PRECISION b(n),sa(*),x(n)
+      INTEGER i,j,k
+      if (ija(1).ne.n+2) pause 'mismatched vector and matrix in sprstx'
+      do 11 i=1,n
+        b(i)=sa(i)*x(i)
+11    continue
+      do 13 i=1,n
+        do 12 k=ija(i),ija(i+1)-1
+          j=ija(k)
+          b(j)=b(j)+sa(k)*x(i)
+12      continue
+13    continue
+      return
+      END