POEQUB: computes row and column scalings intended to equilibrate a Hermitian positive definite matrix A and reduce its condition number (with respect to the two-norm). S contains the scale factors, S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This choice of S puts the condition number of B within a factor N of the smallest possible condition number over all possible diagonal scalings. This routine differs from CPOEQU by restricting the scaling factors to a power of the radix. Barring over- and underflow, scaling by these factors introduces no additional rounding errors. However, the scaled diagonal entries are no longer approximately 1 but lie between sqrt(radix) and 1/sqrt(radix).
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| pure subroutine | cpoequb (n, a, lda, s, scond, amax, info) |
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| | la_cpoequb |
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| pure subroutine | dpoequb (n, a, lda, s, scond, amax, info) |
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| | la_dpoequb |
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| | la_qpoequb |
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| pure subroutine | spoequb (n, a, lda, s, scond, amax, info) |
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| | la_spoequb |
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| | la_wpoequb |
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| pure subroutine | zpoequb (n, a, lda, s, scond, amax, info) |
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| | la_zpoequb |
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POEQUB: computes row and column scalings intended to equilibrate a Hermitian positive definite matrix A and reduce its condition number (with respect to the two-norm). S contains the scale factors, S(i) = 1/sqrt(A(i,i)), chosen so that the scaled matrix B with elements B(i,j) = S(i)*A(i,j)*S(j) has ones on the diagonal. This choice of S puts the condition number of B within a factor N of the smallest possible condition number over all possible diagonal scalings. This routine differs from CPOEQU by restricting the scaling factors to a power of the radix. Barring over- and underflow, scaling by these factors introduces no additional rounding errors. However, the scaled diagonal entries are no longer approximately 1 but lie between sqrt(radix) and 1/sqrt(radix).
◆ cpoequb()
| pure subroutine la_lapack::poequb::cpoequb |
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integer(ilp), intent(in) | n, |
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complex(sp), dimension(lda,*), intent(in) | a, |
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integer(ilp), intent(in) | lda, |
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real(sp), dimension(*), intent(out) | s, |
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real(sp), intent(out) | scond, |
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real(sp), intent(out) | amax, |
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integer(ilp), intent(out) | info ) |
◆ dpoequb()
| pure subroutine la_lapack::poequb::dpoequb |
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integer(ilp), intent(in) | n, |
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real(dp), dimension(lda,*), intent(in) | a, |
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integer(ilp), intent(in) | lda, |
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real(dp), dimension(*), intent(out) | s, |
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real(dp), intent(out) | scond, |
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real(dp), intent(out) | amax, |
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integer(ilp), intent(out) | info ) |
◆ la_cpoequb()
| la_lapack::poequb::la_cpoequb |
◆ la_dpoequb()
| la_lapack::poequb::la_dpoequb |
◆ la_qpoequb()
| la_lapack::poequb::la_qpoequb |
◆ la_spoequb()
| la_lapack::poequb::la_spoequb |
◆ la_wpoequb()
| la_lapack::poequb::la_wpoequb |
◆ la_zpoequb()
| la_lapack::poequb::la_zpoequb |
◆ spoequb()
| pure subroutine la_lapack::poequb::spoequb |
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integer(ilp), intent(in) | n, |
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real(sp), dimension(lda,*), intent(in) | a, |
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integer(ilp), intent(in) | lda, |
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real(sp), dimension(*), intent(out) | s, |
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real(sp), intent(out) | scond, |
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real(sp), intent(out) | amax, |
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integer(ilp), intent(out) | info ) |
◆ zpoequb()
| pure subroutine la_lapack::poequb::zpoequb |
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integer(ilp), intent(in) | n, |
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complex(dp), dimension(lda,*), intent(in) | a, |
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integer(ilp), intent(in) | lda, |
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real(dp), dimension(*), intent(out) | s, |
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real(dp), intent(out) | scond, |
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real(dp), intent(out) | amax, |
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integer(ilp), intent(out) | info ) |
The documentation for this interface was generated from the following file:
