SUBROUTINE SLAKF2( M, N, A, LDA, B, D, E, Z, LDZ ) * * -- LAPACK test routine (version 3.1) -- * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. * November 2006 * * .. Scalar Arguments .. INTEGER LDA, LDZ, M, N * .. * .. Array Arguments .. REAL A( LDA, * ), B( LDA, * ), D( LDA, * ), \$ E( LDA, * ), Z( LDZ, * ) * .. * * Purpose * ======= * * Form the 2*M*N by 2*M*N matrix * * Z = [ kron(In, A) -kron(B', Im) ] * [ kron(In, D) -kron(E', Im) ], * * where In is the identity matrix of size n and X' is the transpose * of X. kron(X, Y) is the Kronecker product between the matrices X * and Y. * * Arguments * ========= * * M (input) INTEGER * Size of matrix, must be >= 1. * * N (input) INTEGER * Size of matrix, must be >= 1. * * A (input) REAL, dimension ( LDA, M ) * The matrix A in the output matrix Z. * * LDA (input) INTEGER * The leading dimension of A, B, D, and E. ( LDA >= M+N ) * * B (input) REAL, dimension ( LDA, N ) * D (input) REAL, dimension ( LDA, M ) * E (input) REAL, dimension ( LDA, N ) * The matrices used in forming the output matrix Z. * * Z (output) REAL, dimension ( LDZ, 2*M*N ) * The resultant Kronecker M*N*2 by M*N*2 matrix (see above.) * * LDZ (input) INTEGER * The leading dimension of Z. ( LDZ >= 2*M*N ) * * ==================================================================== * * .. Parameters .. REAL ZERO PARAMETER ( ZERO = 0.0E+0 ) * .. * .. Local Scalars .. INTEGER I, IK, J, JK, L, MN, MN2 * .. * .. External Subroutines .. EXTERNAL SLASET * .. * .. Executable Statements .. * * Initialize Z * MN = M*N MN2 = 2*MN CALL SLASET( 'Full', MN2, MN2, ZERO, ZERO, Z, LDZ ) * IK = 1 DO 50 L = 1, N * * form kron(In, A) * DO 20 I = 1, M DO 10 J = 1, M Z( IK+I-1, IK+J-1 ) = A( I, J ) 10 CONTINUE 20 CONTINUE * * form kron(In, D) * DO 40 I = 1, M DO 30 J = 1, M Z( IK+MN+I-1, IK+J-1 ) = D( I, J ) 30 CONTINUE 40 CONTINUE * IK = IK + M 50 CONTINUE * IK = 1 DO 90 L = 1, N JK = MN + 1 * DO 80 J = 1, N * * form -kron(B', Im) * DO 60 I = 1, M Z( IK+I-1, JK+I-1 ) = -B( J, L ) 60 CONTINUE * * form -kron(E', Im) * DO 70 I = 1, M Z( IK+MN+I-1, JK+I-1 ) = -E( J, L ) 70 CONTINUE * JK = JK + M 80 CONTINUE * IK = IK + M 90 CONTINUE * RETURN * * End of SLAKF2 * END