SOPMTR overwrites the general real M-by-N matrix C with


                 SIDE = 'L'     SIDE = 'R'


 TRANS = 'N':      Q * C          C * Q


 TRANS = 'T':      Q**T * C       C * Q**T


 where Q is a real orthogonal matrix of order nq, with nq = m if


 SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of


 nq-1 elementary reflectors, as returned by SSPTRD using packed


 storage:


 if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);


 if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).

SIDE

          SIDE is CHARACTER*1


          = 'L': apply Q or Q**T from the Left;


          = 'R': apply Q or Q**T from the Right.

UPLO

          UPLO is CHARACTER*1


          = 'U': Upper triangular packed storage used in previous


                 call to SSPTRD;


          = 'L': Lower triangular packed storage used in previous


                 call to SSPTRD.

TRANS

          TRANS is CHARACTER*1


          = 'N':  No transpose, apply Q;


          = 'T':  Transpose, apply Q**T.

M

          M is INTEGER


          The number of rows of the matrix C. M >= 0.

N

          N is INTEGER


          The number of columns of the matrix C. N >= 0.

AP

          AP is REAL array, dimension


                               (M*(M+1)/2) if SIDE = 'L'


                               (N*(N+1)/2) if SIDE = 'R'


          The vectors which define the elementary reflectors, as


          returned by SSPTRD.  AP is modified by the routine but


          restored on exit.

TAU

          TAU is REAL array, dimension (M-1) if SIDE = 'L'


                                     or (N-1) if SIDE = 'R'


          TAU(i) must contain the scalar factor of the elementary


          reflector H(i), as returned by SSPTRD.

C

          C is REAL array, dimension (LDC,N)


          On entry, the M-by-N matrix C.


          On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.

LDC

          LDC is INTEGER


          The leading dimension of the array C. LDC >= max(1,M).

WORK

          WORK is REAL array, dimension


                                   (N) if SIDE = 'L'


                                   (M) if SIDE = 'R'

INFO

          INFO is INTEGER


          = 0:  successful exit


          < 0:  if INFO = -i, the i-th argument had an illegal value

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NAG Ltd.

December 2016