C DSP 10
C ..................................................................DSP 20
C DSP 30
C SUBROUTINE DCSP DSP 40
C DSP 50
C PURPOSE DSP 60
C COMPUTE THE VALUES OF THE SHIFTED CHEBYSHEV POLYNOMIALS DSP 70
C TS(N,X) FOR ARGUMENT X AND ORDERS 0 UP TO N. DSP 80
C DSP 90
C USAGE DSP 100
C CALL DCSP(Y,X,N) DSP 110
C DSP 120
C DESCRIPTION OF PARAMETERS DSP 130
C Y - RESULT VECTOR OF DIMENSION N+1 CONTAINING THE VALUESDSP 140
C OF SHIFTED CHEBYSHEV POLYNOMIALS OF ORDER 0 UP TO N DSP 150
C FOR GIVEN ARGUMENT X. DSP 160
C DOUBLE PRECISION VECTOR. DSP 170
C VALUES ARE ORDERED FROM LOW TO HIGH ORDER DSP 180
C X - ARGUMENT OF SHIFTED CHEBYSHEV POLYNOMIAL DSP 190
C DOUBLE PRECISION VARIABLE. DSP 200
C N - ORDER OF SHIFTED CHEBYSHEV POLYNOMIAL DSP 210
C DSP 220
C REMARKS DSP 230
C N LESS THAN 0 IS TREATED AS IF N WERE 0 DSP 240
C DSP 250
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED DSP 260
C NONE DSP 270
C DSP 280
C METHOD DSP 290
C EVALUATION IS BASED ON THE RECURRENCE EQUATION FOR DSP 300
C SHIFTED CHEBYSHEV POLYNOMIALS TS(N,X) DSP 310
C TS(N+1,X)=(4*X-2)*TS(N,X)-TS(N-1,X), DSP 320
C WHERE THE FIRST TERM IN BRACKETS IS THE ORDER, DSP 330
C THE SECOND IS THE ARGUMENT. DSP 340
C STARTING VALUES ARE TS(0,X)=1, TS(1,X)=2*X-1. DSP 350
C DSP 360
C ..................................................................DSP 370
C DSP 380
SUBROUTINE DCSP(Y,X,N) DSP 390
C DSP 400
DIMENSION Y(1) DSP 410
DOUBLE PRECISION Y,X,F DSP 420
C DSP 430
C TEST OF ORDER DSP 440
Y(1)=1.D0 DSP 450
IF(N)1,1,2 DSP 460
1 RETURN DSP 470
C DSP 480
2 Y(2)=X+X-1.D0 DSP 490
IF(N-1)1,1,3 DSP 500
C DSP 510
C INITIALIZATION DSP 520
3 F=Y(2)+Y(2) DSP 530
C DSP 540
DO 4 I=2,N DSP 550
4 Y(I+1)=F*Y(I)-Y(I-1) DSP 560
RETURN DSP 570
END DSP 580