C C .................................................................. C C SUBROUTINE CSP C C PURPOSE C COMPUTE THE VALUES OF THE SHIFTED CHEBYSHEV POLYNOMIALS C TS(N,X) FOR ARGUMENT X AND ORDERS 0 UP TO N. C C USAGE C CALL CSP(Y,X,N) C C DESCRIPTION OF PARAMETERS C Y - RESULT VECTOR OF DIMENSION N+1 CONTAINING THE VALUES C OF SHIFTED CHEBYSHEV POLYNOMIALS OF ORDER 0 UP TO N C FOR GIVEN ARGUMENT X. C VALUES ARE ORDERED FROM LOW TO HIGH ORDER C X - ARGUMENT OF SHIFTED CHEBYSHEV POLYNOMIAL C N - ORDER OF SHIFTED CHEBYSHEV POLYNOMIAL C C REMARKS C N LESS THAN 0 IS TREATED AS IF N WERE 0 C C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED C NONE C C METHOD C EVALUATION IS BASED ON THE RECURRENCE EQUATION FOR C SHIFTED CHEBYSHEV POLYNOMIALS TS(N,X) C TS(N+1,X)=(4*X-2)*TS(N,X)-TS(N-1,X), C WHERE THE FIRST TERM IN BRACKETS IS THE ORDER, C THE SECOND IS THE ARGUMENT. C STARTING VALUES ARE TS(0,X)=1, TS(1,X)=2*X-1. C C .................................................................. C SUBROUTINE CSP(Y,X,N) C DIMENSION Y(1) C C TEST OF ORDER Y(1)=1. IF(N)1,1,2 1 RETURN C 2 Y(2)=X+X-1. IF(N-1)1,1,3 C C INITIALIZATION 3 F=Y(2)+Y(2) C DO 4 I=2,N 4 Y(I+1)=F*Y(I)-Y(I-1) RETURN END