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Add note to *TRTRS and *TBTRS about how only exact singularity is che…
…cked
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GYT committed Jul 25, 2024
commit 5475251aba635560a9e006febf29348a574b3b6c
10 changes: 8 additions & 2 deletions SRC/ctbtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B, A**T * X = B, or A**H * X = B,
*>
*> where A is a triangular band matrix of order N, and B is an
*> N-by-NRHS matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular band matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/ctrtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B, A**T * X = B, or A**H * X = B,
*>
*> where A is a triangular matrix of order N, and B is an N-by-NRHS
*> matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/dtbtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B or A**T * X = B,
*>
*> where A is a triangular band matrix of order N, and B is an
*> N-by NRHS matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular band matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/dtrtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B or A**T * X = B,
*>
*> where A is a triangular matrix of order N, and B is an N-by-NRHS
*> matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/stbtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B or A**T * X = B,
*>
*> where A is a triangular band matrix of order N, and B is an
*> N-by NRHS matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular band matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/strtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B or A**T * X = B,
*>
*> where A is a triangular matrix of order N, and B is an N-by-NRHS
*> matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/ztbtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B, A**T * X = B, or A**H * X = B,
*>
*> where A is a triangular band matrix of order N, and B is an
*> N-by-NRHS matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular band matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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10 changes: 8 additions & 2 deletions SRC/ztrtrs.f
Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,14 @@
*>
*> A * X = B, A**T * X = B, or A**H * X = B,
*>
*> where A is a triangular matrix of order N, and B is an N-by-NRHS
*> matrix. A check is made to verify that A is nonsingular.
*> where A is a triangular matrix of order N, and B is an N-by-NRHS matrix.
*>
*> This subroutine verifies that A is nonsingular, but callers should note that only exact
*> singularity is detected. It is conceivable for one or more diagonal elements of A to be
*> subnormally tiny numbers without this subroutine signalling an error.
*>
*> If a possible loss of numerical precision due to near-singular matrices is a concern, the
*> caller should verify that A is nonsingular within some tolerance before calling this subroutine.
*> \endverbatim
*
* Arguments:
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