,
of a finite Chebyshev series,
RCHPWS and DCHWPS calculate the coefficients
, 
of the equivalent polynomial:
| Author(s): K.S. Kölbig | Library: MATHLIB |
| Submitter: | Submitted: 15.02.1994 |
| Language: Fortran | Revised: |
Subroutine subprograms RCHPWS, RPWCHS and DCHPWS, DPWCHS perform the conversion of a finite Chebyshev series to a finite power series (i.e. a polynomial) and vice versa.
Thus, given the coefficients ,
of a finite Chebyshev series,
RCHPWS and DCHWPS calculate the coefficients
, of the equivalent polynomial:
Conversely, given the coefficients 
,
of a power series,
RPWCHS and DPWCHS calculate the coefficients
, 
of the equivalent finite Chebyshev series:
In both cases, 
is the Chebyshev polynomial of degree j.
Note that sometimes the constant term in the Chebyshev series is
defined differently, i.e. 
instead of 
.
Here, the definition of Ref. 1 is used.
On computers other than CDC or Cray, only the double-precision versions DCHPWS and DPWCHS are available. On CDC and Cray computers, only the single-precision versions RCHPWS and RPWCHS are available.
Structure:
SUBROUTINE subprograms
User Entry Names: RCHPWS, RPWCHS,
DCHPWS, DPWCHS
Files referenced: Unit 6
Usage:
For 
(type REAL), 
(type
DOUBLE PRECISION),
CALL tCHPWS(N,C,A)
. On entry, C must contain
the coefficients 
, 
of the Chebyshev expansion.
. On exit, A contains the
coefficients 
, 
of the power series expansion.
CALL tPWCHS(N,A,C)
. On entry, A must contain
the coefficients 
, 
of the polynomial.
. On exit, C contains the
coefficients 
, 
of the Chebyshev expansion.
Error handling:
Error E408.1: 
or 
.
A message is written on Unit 6, unless subroutine MTLSET
(N002) has been called.
References:
