5 * Revision 1.1.1.1 1996/04/01 15:02:27 mclareni
10 SUBROUTINE SLV (M,N,QR,ALPHA,IPIVOT,R,Y,Z)
11 DIMENSION QR(M,N),ALPHA(N),R(M),Y(N),IPIVOT(N),Z(N)
13 C USING THE VECTORS U, WHOSE NON-ZERO COMPONENTS ARE
14 C STORED ON AND BELOW THE MAIN DIAGONAL OF QR(M,N), SLV
15 C APPLIES THE N TRANSFORMATIONS (I - BETA UT) TO THE
16 C RIGHT HAND SIDE R(M). FROM THE REDUCED MATRIX GIVEN IN
17 C ALPHA(N) AND THE UPPER RIGHT TRIANGULAR PART OF QR,
18 C SLV THEN COMPUTES BY BACK-SUBSTITUTION, AN APPROXIMATE
19 C SOLUTION TO THE LINEAR SYSTEM. THE COMPONENTS OF THE
20 C SOLUTION VECTOR ARE STORED IN Y(N) IN THE ORDER PRESCRIBED
24 GAMMA=PROD1(QR(1,J),R,J,M)/(ALPHA(J)*QR(J,J))
26 5 R(I)=R(I)+GAMMA*QR(I,J)
33 15 Z(L)=-PROD2(QR,Z,M,LA,N,L,-R(L))/ALPHA(L)