DSYL01 tests DTRSYL and DTRSYL3, routines for solving the Sylvester matrix


 equation


    op(A)*X + ISGN*X*op(B) = scale*C,


 A and B are assumed to be in Schur canonical form, op() represents an


 optional transpose, and ISGN can be -1 or +1.  Scale is an output


 less than or equal to 1, chosen to avoid overflow in X.


 The test code verifies that the following residual does not exceed


 the provided threshold:


    norm(op(A)*X + ISGN*X*op(B) - scale*C) /


        (EPS*max(norm(A),norm(B))*norm(X))


 This routine complements DGET35 by testing with larger,


 random matrices, of which some require rescaling of X to avoid overflow.

THRESH

          THRESH is DOUBLE PRECISION


          A test will count as 'failed' if the residual, computed as


          described above, exceeds THRESH.

NFAIL

          NFAIL is INTEGER array, dimension (3)


          NFAIL(1) = No. of times residual DTRSYL exceeds threshold THRESH


          NFAIL(2) = No. of times residual DTRSYL3 exceeds threshold THRESH


          NFAIL(3) = No. of times DTRSYL3 and DTRSYL deviate

RMAX

          RMAX is DOUBLE PRECISION, dimension (2)


          RMAX(1) = Value of the largest test ratio of DTRSYL


          RMAX(2) = Value of the largest test ratio of DTRSYL3

NINFO

          NINFO is INTEGER array, dimension (2)


          NINFO(1) = No. of times DTRSYL returns an expected INFO


          NINFO(2) = No. of times DTRSYL3 returns an expected INFO

KNT

          KNT is INTEGER


          Total number of examples tested.