diff options
Diffstat (limited to 'SRC/ssytd2.f')
| -rw-r--r-- | SRC/ssytd2.f | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/SRC/ssytd2.f b/SRC/ssytd2.f index 576450d0..e15280ee 100644 --- a/SRC/ssytd2.f +++ b/SRC/ssytd2.f @@ -17,7 +17,7 @@ * ======= * * SSYTD2 reduces a real symmetric matrix A to symmetric tridiagonal -* form T by an orthogonal similarity transformation: Q' * A * Q = T. +* form T by an orthogonal similarity transformation: Q**T * A * Q = T. * * Arguments * ========= @@ -79,7 +79,7 @@ * * Each H(i) has the form * -* H(i) = I - tau * v * v' +* H(i) = I - tau * v * v**T * * where tau is a real scalar, and v is a real vector with * v(i+1:n) = 0 and v(i) = 1; v(1:i-1) is stored on exit in @@ -92,7 +92,7 @@ * * Each H(i) has the form * -* H(i) = I - tau * v * v' +* H(i) = I - tau * v * v**T * * where tau is a real scalar, and v is a real vector with * v(1:i) = 0 and v(i+1) = 1; v(i+2:n) is stored on exit in A(i+2:n,i), @@ -163,7 +163,7 @@ * DO 10 I = N - 1, 1, -1 * -* Generate elementary reflector H(i) = I - tau * v * v' +* Generate elementary reflector H(i) = I - tau * v * v**T * to annihilate A(1:i-1,i+1) * CALL SLARFG( I, A( I, I+1 ), A( 1, I+1 ), 1, TAUI ) @@ -180,13 +180,13 @@ CALL SSYMV( UPLO, I, TAUI, A, LDA, A( 1, I+1 ), 1, ZERO, $ TAU, 1 ) * -* Compute w := x - 1/2 * tau * (x'*v) * v +* Compute w := x - 1/2 * tau * (x**T * v) * v * ALPHA = -HALF*TAUI*SDOT( I, TAU, 1, A( 1, I+1 ), 1 ) CALL SAXPY( I, ALPHA, A( 1, I+1 ), 1, TAU, 1 ) * * Apply the transformation as a rank-2 update: -* A := A - v * w' - w * v' +* A := A - v * w**T - w * v**T * CALL SSYR2( UPLO, I, -ONE, A( 1, I+1 ), 1, TAU, 1, A, $ LDA ) @@ -203,7 +203,7 @@ * DO 20 I = 1, N - 1 * -* Generate elementary reflector H(i) = I - tau * v * v' +* Generate elementary reflector H(i) = I - tau * v * v**T * to annihilate A(i+2:n,i) * CALL SLARFG( N-I, A( I+1, I ), A( MIN( I+2, N ), I ), 1, @@ -221,14 +221,14 @@ CALL SSYMV( UPLO, N-I, TAUI, A( I+1, I+1 ), LDA, $ A( I+1, I ), 1, ZERO, TAU( I ), 1 ) * -* Compute w := x - 1/2 * tau * (x'*v) * v +* Compute w := x - 1/2 * tau * (x**T * v) * v * ALPHA = -HALF*TAUI*SDOT( N-I, TAU( I ), 1, A( I+1, I ), $ 1 ) CALL SAXPY( N-I, ALPHA, A( I+1, I ), 1, TAU( I ), 1 ) * * Apply the transformation as a rank-2 update: -* A := A - v * w' - w * v' +* A := A - v * w' - w * v**T * CALL SSYR2( UPLO, N-I, -ONE, A( I+1, I ), 1, TAU( I ), 1, $ A( I+1, I+1 ), LDA ) |