PROCEDURE lubksb(a: StateMatrix; n: INTEGER; indx: StateVector; VAR b: StateVector);
{
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## Version control history
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## $Id$
## $Log$
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}
(* Programs using LUBKSB must define the types
TYPE
glnarray = ARRAY [1..n] OF real;
glindx = ARRAY [1..n] OF integer;
glnpbynp = ARRAY [1..np,1..np] OF real;
in the main routine *)
VAR
j,ip,ii,i: integer;
sum: real;
BEGIN
ii := 0;
FOR i := 1 TO n DO BEGIN
ip := indx[i];
sum := b[ip];
b[ip] := b[i];
IF (ii <> 0) THEN BEGIN
FOR j := ii TO i-1 DO BEGIN
sum := sum-a[i,j]*b[j]
END
END ELSE IF (sum <> 0.0) THEN BEGIN
ii := i
END;
b[i] := sum
END;
FOR i := n DOWNTO 1 DO BEGIN
sum := b[i];
IF (i < n) THEN BEGIN
FOR j := i+1 TO n DO BEGIN
sum := sum-a[i,j]*b[j]
END
END;
b[i] := sum/a[i,i]
END
END;